Actinide

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The atomic bomb dropped on Nagasaki had a plutonium charge.

 

The actinide /ˈæktɪnaɪd/ or actinoid /ˈæktɪnɔɪd/ (IUPAC nomenclature) series encompasses the 15 metallic chemical elements with atomic numbers from 89 to 103, actinium through lawrencium.

Strictly speaking, both actinium and lawrencium have been labeled as group 3 elements, but both elements are often included in any general discussion of the chemistry of the actinide elements. Actinium is the more often omitted of the two, because its placement as a group 3 element is somewhat more common in texts and for semantic reasons: since "actinide" means "like actinium", it has been argued that actinium cannot logically be an actinide, even though IUPAC acknowledges its inclusion based on common usage.

The actinide series derives its name from the first element in the series, actinium. The informal chemical symbol An is used in general discussions of actinide chemistry to refer to any actinide. All but one of the actinides are f-block elements, with the exception being either actinium or lawrencium. The series mostly corresponds to the filling of the 5f electron shell, although actinium and thorium lack any f-electrons, and curium and lawrencium have the same number as the preceding element. In comparison with the lanthanides, also mostly f-block elements, the actinides show much more variable valence. They all have very large atomic and ionic radii and exhibit an unusually large range of physical properties. While actinium and the late actinides (from americium onwards) behave similarly to the lanthanides, the elements thorium, protactinium, and uranium are much more similar to transition metals in their chemistry, with neptunium and plutonium occupying an intermediate position.

All actinides are radioactive and release energy upon radioactive decay; naturally occurring uranium and thorium, and synthetically produced plutonium are the most abundant actinides on Earth. These are used in nuclear reactors and nuclear weapons. Uranium and thorium also have diverse current or historical uses, and americium is used in the ionization chambers of most modern smoke detectors. 

Of the actinides, primordial thorium and uranium occur naturally in substantial quantities. The radioactive decay of uranium produces transient amounts of actinium and protactinium, and atoms of neptunium and plutonium are occasionally produced from transmutation reactions in uranium ores. The other actinides are purely synthetic elements. Nuclear weapons tests have released at least six actinides heavier than plutonium into the environment; analysis of debris from a 1952 hydrogen bomb explosion showed the presence of americium, curium, berkelium, californium, einsteinium and fermium.

In presentations of the periodic table, the lanthanides and the actinides are customarily shown as two additional rows below the main body of the table, with placeholders or else a selected single element of each series (either lanthanum or lutetium, and either actinium or lawrencium, respectively) shown in a single cell of the main table, between barium and hafnium, and radium and rutherfordium, respectively. This convention is entirely a matter of aesthetics and formatting practicality; a rarely used wide-formatted periodic table inserts the lanthanide and actinide series in their proper places, as parts of the table's sixth and seventh rows (periods).

Discovery, isolation and synthesis

Synthesis of transuranium elements

Element	Year	Method
Neptunium	1940	Bombarding 238U by neutrons
Plutonium	1941	Bombarding 238U by deuterons
Americium	1944	Bombarding 239Pu by neutrons
Curium	1944	Bombarding 239Pu by α-particles
Berkelium	1949	Bombarding 241Am by α-particles
Californium	1950	Bombarding 242Cm by α-particles
Einsteinium	1952	As a product of nuclear explosion
Fermium	1952	As a product of nuclear explosion
Mendelevium	1955	Bombarding 253Es by α-particles
Nobelium	1965	Bombarding 243Am by 15N or 238U with 22Ne
Lawrencium	1961 –1971	Bombarding 252Cf by 10B or 11B and of 243Am with 18O

Like the lanthanides, the actinides form a family of elements with similar properties. Within the actinides, there are two overlapping groups: transuranium elements, which follow uranium in the periodic table—and transplutonium elements, which follow plutonium. Compared to the lanthanides, which (except for promethium) are found in nature in appreciable quantities, most actinides are rare. The majority of them do not even occur in nature, and of those that do, only thorium and uranium do so in more than trace quantities. The most abundant or easily synthesized actinides are uranium and thorium, followed by plutonium, americium, actinium, protactinium, neptunium, and curium.^\

 

The existence of transuranium elements was suggested by Enrico Fermi based on his experiments in 1934. However, even though four actinides were known by that time, it was not yet understood that they formed a family similar to lanthanides. The prevailing view that dominated early research into transuranics was that they were regular elements in the 7th period, with thorium, protactinium and uranium corresponding to 6th-period hafnium, tantalum and tungsten, respectively. Synthesis of transuranics gradually undermined this point of view. By 1944 an observation that curium failed to exhibit oxidation states above 4 (whereas its supposed 6th period homolog, platinum, can reach oxidation state of 6) prompted Glenn Seaborg to formulate a so-called "actinide hypothesis". Studies of known actinides and discoveries of further transuranic elements provided more data in support of this point of view, but the phrase "actinide hypothesis" (the implication being that a "hypothesis" is something that has not been decisively proven) remained in active use by scientists through the late 1950s.

At present, there are two major methods of producing isotopes of transplutonium elements: (1) irradiation of the lighter elements with either neutrons or (2) accelerated charged particles. The first method is most important for applications, as only neutron irradiation using nuclear reactors allows the production of sizeable amounts of synthetic actinides; however, it is limited to relatively light elements. The advantage of the second method is that elements heavier than plutonium, as well as neutron-deficient isotopes, can be obtained, which are not formed during neutron irradiation.

In 1962–1966, there were attempts in the United States to produce transplutonium isotopes using a series of six underground nuclear explosions. Small samples of rock were extracted from the blast area immediately after the test to study the explosion products, but no isotopes with mass number greater than 257 could be detected, despite predictions that such isotopes would have relatively long half-lives of α-decay. This non-observation was attributed to spontaneous fission owing to the large speed of the products and to other decay channels, such as neutron emission and nuclear fission.

From actinium to uranium

Enrico Fermi suggested the existence of transuranium elements in 1934.

 

Uranium and thorium were the first actinides discovered. Uranium was identified in 1789 by the German chemist Martin Heinrich Klaproth in pitchblende ore. He named it after the planet Uranus, which had been discovered only eight years earlier. Klaproth was able to precipitate a yellow compound (likely sodium diuranate) by dissolving pitchblende in nitric acid and neutralizing the solution with sodium hydroxide. He then reduced the obtained yellow powder with charcoal, and extracted a black substance that he mistook for metal. Only 60 years later, the French scientist Eugène-Melchior Péligot identified it as uranium oxide. He also isolated the first sample of uranium metal by heating uranium tetrachloride with metallic potassium. The atomic mass of uranium was then calculated as 120, but Dmitri Mendeleev in 1872 corrected it to 240 using his periodicity laws. This value was confirmed experimentally in 1882 by K. Zimmerman.

Thorium oxide was discovered by Friedrich Wöhler in the mineral Thorianite, which was found in Norway (1827). Jöns Jacob Berzelius characterized this material in more detail by in 1828. By reduction of thorium tetrachloride with potassium, he isolated the metal and named it thorium after the Norse god of thunder and lightning Thor. The same isolation method was later used by Péligot for uranium.

Actinium was discovered in 1899 by André-Louis Debierne, an assistant of Marie Curie, in the pitchblende waste left after removal of radium and polonium. He described the substance (in 1899) as similar to titanium and (in 1900) as similar to thorium. The discovery of actinium by Debierne was however questioned in 1971 and 2000, arguing that Debierne's publications in 1904 contradicted his earlier work of 1899–1900. This view instead credits the 1902 work of Friedrich Oskar Giesel, who discovered a radioactive element named emanium that behaved similarly to lanthanum. The name actinium comes from the Greek aktis, aktinos (ακτίς, ακτίνος), meaning beam or ray. This metal was discovered not by its own radiation but by the radiation of the daughter products. Owing to the close similarity of actinium and lanthanum and low abundance, pure actinium could only be produced in 1950. The term actinide was probably introduced by Victor Goldschmidt in 1937.

Protactinium was possibly isolated in 1900 by William Crookes. It was first identified in 1913, when Kasimir Fajans and Oswald Helmuth Göhring encountered the short-lived isotope ^234mPa (half-life 1.17 minutes) during their studies of the ²³⁸U decay. They named the new element brevium (from Latin brevis meaning brief); the name was changed to protoactinium (from Greek πρῶτος + ἀκτίς meaning "first beam element") in 1918 when two groups of scientists, led by the Austrian Lise Meitner and Otto Hahn of Germany and Frederick Soddy and John Cranston of Great Britain, independently discovered the much longer-lived ²³¹Pa. The name was shortened to protactinium in 1949. This element was little characterized until 1960, when A. G. Maddock and his co-workers in the U.K. isolated 130 grams of protactinium from 60 tonnes of waste left after extraction of uranium from its ore.

Neptunium and above

Neptunium (named for the planet Neptune, the next planet out from Uranus, after which uranium was named) was discovered by Edwin McMillan and Philip H. Abelson in 1940 in Berkeley, California. They produced the ²³⁹Np isotope (half-life = 2.4 days) by bombarding uranium with slow neutrons. It was the first transuranium element produced synthetically.

Glenn T. Seaborg and his group at the University of California at Berkeley synthesized Pu, Am, Cm, Bk, Cf, Es, Fm, Md, No and element 106, which was later named seaborgium in his honor while he was still living. They also synthesized more than a hundred actinide isotopes.

 

Transuranium elements do not occur in sizeable quantities in nature and are commonly synthesized via nuclear reactions conducted with nuclear reactors. For example, under irradiation with reactor neutrons, uranium-238 partially converts to plutonium-239:

${\displaystyle {\ce {{^{238}_{92}U}+{}_{0}^{1}n->{}_{92}^{239}U->[\beta ^{-}][23.5\ {\ce {min}}]{}_{93}^{239}Np->[\beta ^{-}][2.3\ {\ce {days}}]{}_{94}^{239}Pu}}\left({\ce {->[\alpha ][2.4\cdot 10^{4}\ {\ce {years}}]}}\right){\ce {^{235}_{92}U}}}$

This synthesis reaction was used by Fermi and his collaborators in their design of the reactors located at the Hanford Site, which produced significant amounts of plutonium-239 for the nuclear weapons of the Manhattan Project and the United States' post-war nuclear arsenal.

Actinides with the highest mass numbers are synthesized by bombarding uranium, plutonium, curium and californium with ions of nitrogen, oxygen, carbon, neon or boron in a particle accelerator. So, nobelium was produced by bombarding uranium-238 with neon-22 as

${\displaystyle {\ce {_{92}^{238}U + _{10}^{22}Ne -> _{102}^{256}No + 4_0^1n}}}$.

The first isotopes of transplutonium elements, americium-241 and curium-242, were synthesized in 1944 by Glenn T. Seaborg, Ralph A. James and Albert Ghiorso. Curium-242 was obtained by bombarding plutonium-239 with 32-MeV α-particles

${\displaystyle {\ce {_{94}^{239}Pu + _2^4He -> _{96}^{242}Cm + _0^1n}}}$.

The americium-241 and curium-242 isotopes also were produced by irradiating plutonium in a nuclear reactor. The latter element was named after Marie Curie and her husband Pierre who are noted for discovering radium and for their work in radioactivity.

Bombarding curium-242 with α-particles resulted in an isotope of californium ²⁴⁵Cf (1950), and a similar procedure yielded in 1949 berkelium-243 from americium-241. The new elements were named after Berkeley, California, by analogy with its lanthanide homologue terbium, which was named after the village of Ytterby in Sweden.

In 1945, B. B. Cunningham obtained the first bulk chemical compound of a transplutonium element, namely americium hydroxide. Over the next three to four years, milligram quantities of americium and microgram amounts of curium were accumulated that allowed production of isotopes of berkelium (Thomson, 1949) and californium (Thomson, 1950). Sizeable amounts of these elements were produced only in 1958 (Burris B. Cunningham and Stanley G. Thomson), and the first californium compound (0.3 µg of CfOCl) was obtained only in 1960 by B. B. Cunningham and J. C. Wallmann.

Einsteinium and fermium were identified in 1952–1953 in the fallout from the "Ivy Mike" nuclear test (1 November 1952), the first successful test of a hydrogen bomb. Instantaneous exposure of uranium-238 to a large neutron flux resulting from the explosion produced heavy isotopes of uranium, including uranium-253 and uranium-255, and their β-decay yielded einsteinium-253 and fermium-255. The discovery of the new elements and the new data on neutron capture were initially kept secret on the orders of the U.S. military until 1955 due to Cold War tensions. Nevertheless, the Berkeley team were able to prepare einsteinium and fermium by civilian means, through the neutron bombardment of plutonium-239, and published this work in 1954 with the disclaimer that it was not the first studies that had been carried out on the elements. The "Ivy Mike" studies were declassified and published in 1955. The first significant (submicrograms) amounts of einsteinium were produced in 1961 by Cunningham and colleagues, but this has not been done for fermium yet.

The first isotope of mendelevium, ²⁵⁶Md (half-life 87 min), was synthesized by Albert Ghiorso, Glenn T. Seaborg, Gregory R. Choppin, Bernard G. Harvey and Stanley G. Thompson when they bombarded an ²⁵³Es target with alpha particles in the 60-inch cyclotron of Berkeley Radiation Laboratory; this was the first isotope of any element to be synthesized one atom at a time.

There were several attempts to obtain isotopes of nobelium by Swedish (1957) and American (1958) groups, but the first reliable result was the synthesis of ²⁵⁶No by the Russian group (Georgy Flyorov et al.) in 1965, as acknowledged by the IUPAC in 1992. In their experiments, Flyorov et al. bombarded uranium-238 with neon-22.

In 1961, Ghiorso et al. obtained the first isotope of lawrencium by irradiating californium (mostly californium-252) with boron-10 and boron-11 ions. The mass number of this isotope was not clearly established (possibly 258 or 259) at the time. In 1965, ²⁵⁶Lr was synthesized by Flyorov et al. from ²⁴³Am and ¹⁸O. Thus IUPAC recognized the nuclear physics teams at Dubna and Berkeley as the co-discoverers of lawrencium.

Isotopes

Actinides have 89−103 protons and usually 117−159 neutrons.

 

Thirty-one isotopes of actinium and eight excited isomeric states of some of its nuclides were identified by 2010. Three isotopes, ²²⁵Ac, ²²⁷Ac and ²²⁸Ac, were found in nature and the others were produced in the laboratory; only the three natural isotopes are used in applications. Actinium-225 is a member of the radioactive neptunium series; it was first discovered in 1947 as a decay product of uranium-233, it is an α-emitter with a half-life of 10 days. Actinium-225 is less available than actinium-228, but is more promising in radiotracer applications. Actinium-227 (half-life 21.77 years) occurs in all uranium ores, but in small quantities. One gram of uranium (in radioactive equilibrium) contains only 2×10⁻¹⁰ gram of ²²⁷Ac. Actinium-228 is a member of the radioactive thorium series formed by the decay of ²²⁸Ra; it is a β⁻ emitter with a half-life of 6.15 hours. In one tonne of thorium there is 5×10⁻⁸ gram of ²²⁸Ac. It was discovered by Otto Hahn in 1906.

28 isotopes of protactinium are known with mass numbers 212–239 as well as three excited isomeric states. Only ²³¹Pa and ²³⁴Pa have been found in nature. All the isotopes have short lifetime, except for protactinium-231 (half-life 32,760 years). The most important isotopes are ²³¹Pa and ²³³Pa, which is an intermediate product in obtaining uranium-233 and is the most affordable among artificial isotopes of protactinium. ²³³Pa has convenient half-life and energy of γ-radiation, and thus was used in most studies of protactinium chemistry. Protactinium-233 is a β-emitter with a half-life of 26.97 days.

Uranium has the highest number (25) of both natural and synthetic isotopes. They have mass numbers of 215–242 (except 220 and 241), and three of them, ²³⁴U, ²³⁵U and ²³⁸U, are present in appreciable quantities in nature. Among others, the most important is ²³³U, which is a final product of transformations of ²³²Th irradiated by slow neutrons. ²³³U has a much higher fission efficiency by low-energy (thermal) neutrons, compared e.g. with ²³⁵U. Most uranium chemistry studies were carried out on uranium-238 owing to its long half-life of 4.4×10⁹ years.

There are 23 isotopes of neptunium with mass numbers of 219 and 223–244; they are all highly radioactive. The most popular among scientists are long-lived ²³⁷Np (t_1/2 = 2.20×10⁶ years) and short-lived ²³⁹Np, ²³⁸Np (t_1/2 ~ 2 days).

Eighteen isotopes of americium are known with mass numbers from 229 to 247 (with the exception of 231). The most important are ²⁴¹Am and ²⁴³Am, which are alpha-emitters and also emit soft, but intense γ-rays; both of them can be obtained in an isotopically pure form. Chemical properties of americium were first studied with ²⁴¹Am, but later shifted to ²⁴³Am, which is almost 20 times less radioactive. The disadvantage of ²⁴³Am is production of the short-lived daughter isotope ²³⁹Np, which has to be considered in the data analysis.

Among 19 isotopes of curium, the most accessible are ²⁴²Cm and ²⁴⁴Cm; they are α-emitters, but with much shorter lifetime than the americium isotopes. These isotopes emit almost no γ-radiation, but undergo spontaneous fission with the associated emission of neutrons. More long-lived isotopes of curium (^245–248Cm, all α-emitters) are formed as a mixture during neutron irradiation of plutonium or americium. Upon short irradiation, this mixture is dominated by ²⁴⁶Cm, and then ²⁴⁸Cm begins to accumulate. Both of these isotopes, especially ²⁴⁸Cm, have a longer half-life (3.48×10⁵ years) and are much more convenient for carrying out chemical research than ²⁴²Cm and ²⁴⁴Cm, but they also have a rather high rate of spontaneous fission. ²⁴⁷Cm has the longest lifetime among isotopes of curium (1.56×10⁷ years), but is not formed in large quantities because of the strong fission induced by thermal neutrons. 

Eighteen isotopes of berkelium were identified with mass numbers 233–234, 236, and 238–252. Only ²⁴⁹Bk is available in large quantities; it has a relatively short half-life of 330 days and emits mostly soft β-particles, which are inconvenient for detection. Its alpha radiation is rather weak (1.45×10⁻³% with respect to β-radiation), but is sometimes used to detect this isotope. ²⁴⁷Bk is an alpha-emitter with a long half-life of 1,380 years, but it is hard to obtain in appreciable quantities; it is not formed upon neutron irradiation of plutonium because of the β-stability of isotopes of curium isotopes with mass number below 248.

Isotopes of californium with mass numbers 237–256 are formed in nuclear reactors; californium-253 is a β-emitter and the rest are α-emitters. The isotopes with even mass numbers (²⁵⁰Cf, ²⁵²Cf and ²⁵⁴Cf) have a high rate of spontaneous fission, especially ²⁵⁴Cf of which 99.7% decays by spontaneous fission. Californium-249 has a relatively long half-life (352 years), weak spontaneous fission and strong γ-emission that facilitates its identification. ²⁴⁹Cf is not formed in large quantities in a nuclear reactor because of the slow β-decay of the parent isotope ²⁴⁹Bk and a large cross section of interaction with neutrons, but it can be accumulated in the isotopically pure form as the β-decay product of (pre-selected) ²⁴⁹Bk. Californium produced by reactor-irradiation of plutonium mostly consists of ²⁵⁰Cf and ²⁵²Cf, the latter being predominant for large neutron fluences, and its study is hindered by the strong neutron radiation.

Properties of some transplutonium isotope pairs

Parent isotope	t1/2	Daughter isotope	t1/2	Time to establish radioactive equilibrium
243Am	7370 years	239Np	2.35 days	47.3 days
245Cm	8265 years	241Pu	14 years	129 years
247Cm	1.64×107 years	243Pu	4.95 hours	7.2 days
254Es	270 days	250Bk	3.2 hours	35.2 hours
255Es	39.8 days	255Fm	22 hours	5 days
257Fm	79 days	253Cf	17.6 days	49 days

Among the 18 known isotopes of einsteinium with mass numbers from 240 to 257, the most affordable is ²⁵³Es. It is an α-emitter with a half-life of 20.47 days, a relatively weak γ-emission and small spontaneous fission rate as compared with the isotopes of californium. Prolonged neutron irradiation also produces a long-lived isotope ²⁵⁴Es (t_1/2 = 275.5 days).

Twenty isotopes of fermium are known with mass numbers of 241–260. ²⁵⁴Fm, ²⁵⁵Fm and ²⁵⁶Fm are α-emitters with a short half-life (hours), which can be isolated in significant amounts. ²⁵⁷Fm (t_1/2 = 100 days) can accumulate upon prolonged and strong irradiation. All these isotopes are characterized by high rates of spontaneous fission.

Among the 16 known isotopes of mendelevium (mass numbers from 245 to 260), the most studied is ²⁵⁶Md, which mainly decays through the electron capture (α-radiation is ≈10%) with the half-life of 77 minutes. Another alpha emitter, ²⁵⁸Md, has a half-life of 53 days. Both these isotopes are produced from rare einsteinium (²⁵³Es and ²⁵⁵Es respectively), that therefore limits their availability.

Long-lived isotopes of nobelium and isotopes of lawrencium (and of heavier elements) have relatively short half-lives. For nobelium, 11 isotopes are known with mass numbers 250–260 and 262. The chemical properties of nobelium and lawrencium were studied with ²⁵⁵No (t_1/2 = 3 min) and ²⁵⁶Lr (t_1/2 = 35 s). The longest-lived nobelium isotope, ²⁵⁹No, has a half-life of approximately 1 hour.

Among all of these, the only isotopes that occur in sufficient quantities in nature to be detected in anything more than traces and have a measurable contribution to the atomic weights of the actinides are the primordial ²³²Th, ²³⁵U, and ²³⁸U, and three long-lived decay products of natural uranium, ²³⁰Th, ²³¹Pa, and ²³⁴U. Natural thorium consists of 0.02(2)% ²³⁰Th and 99.98(2)% ²³²Th; natural protactinium consists of 100% ²³¹Pa; and natural uranium consists of 0.0054(5)% ²³⁴U, 0.7204(6)% ²³⁵U, and 99.2742(10)% ²³⁸U.

Distribution in nature

Unprocessed uranium ore

 

Thorium and uranium are the most abundant actinides in nature with the respective mass concentrations of 16 ppm and 4 ppm. Uranium mostly occurs in the Earth's crust as a mixture of its oxides in the minerals uraninite, which is also called pitchblende because of its black color. There are several dozens of other uranium minerals such as carnotite (KUO₂VO₄·3H₂O) and autunite (Ca(UO₂)₂(PO₄)₂·nH₂O). The isotopic composition of natural uranium is ²³⁸U (relative abundance 99.2742%), ²³⁵U (0.7204%) and ²³⁴U (0.0054%); of these ²³⁸U has the largest half-life of 4.51×10⁹ years. The worldwide production of uranium in 2009 amounted to 50,572 tonnes, of which 27.3% was mined in Kazakhstan. Other important uranium mining countries are Canada (20.1%), Australia (15.7%), Namibia (9.1%), Russia (7.0%), and Niger (6.4%).

Content of plutonium in uranium and thorium ores

Ore	Location	Uranium content, %	Mass ratio 239Pu/ore	Ratio 239Pu/U (×1012)
Uraninite	Canada	13.5	9.1×10−12	7.1
Uraninite	Congo	38	4.8×10−12	12
Uraninite	Colorado, US	50	3.8×10−12	7.7
Monazite	Brazil	0.24	2.1×10−14	8.3
Monazite	North Carolina, US	1.64	5.9×10−14	3.6
Fergusonite	-	0.25	<1 span="" style="margin: 0 .15em 0 .25em;">×10−14

<4 span=""> Carnotite - 10 <4 span="" style="margin: 0 .15em 0 .25em;">× 10⁻¹⁴ <0 .4="" span="">

The most abundant thorium minerals are thorianite (ThO₂), thorite (ThSiO₄) and monazite, ((Th,Ca,Ce)PO₄). Most thorium minerals contain uranium and vice versa; and they all have significant fraction of lanthanides. Rich deposits of thorium minerals are located in the United States (440,000 tonnes), Australia and India (~300,000 tonnes each) and Canada (~100,000 tonnes).

The abundance of actinium in the Earth's crust is only about 5×10⁻¹⁵%. Actinium is mostly present in uranium-containing, but also in other minerals, though in much smaller quantities. The content of actinium in most natural objects corresponds to the isotopic equilibrium of parent isotope ²³⁵U, and it is not affected by the weak Ac migration. Protactinium is more abundant (10⁻¹²%) in the Earth's crust than actinium. It was discovered in the uranium ore in 1913 by Fajans and Göhring. As actinium, the distribution of protactinium follows that of ²³⁵U.

The half-life of the longest-lived isotope of neptunium, ²³⁷Np, is negligible compared to the age of the Earth. Thus neptunium is present in nature in negligible amounts produced as intermediate decay products of other isotopes. Traces of plutonium in uranium minerals were first found in 1942, and the more systematic results on ²³⁹Pu are summarized in the table (no other plutonium isotopes could be detected in those samples). The upper limit of abundance of the longest-living isotope of plutonium, ²⁴⁴Pu, is 3×10⁻²⁰%. Plutonium could not be detected in samples of lunar soil. Owing to its scarcity in nature, most plutonium is produced synthetically.

Extraction

Monazite: a major thorium mineral

 

Owing to the low abundance of actinides, their extraction is a complex, multistep process. Fluorides of actinides are usually used because they are insoluble in water and can be easily separated with redox reactions. Fluorides are reduced with calcium, magnesium or barium:

${\displaystyle {\begin{array}{l}{}\\{\ce {2AmF3{}+3Ba->[{\ce {1150-1350^{\circ }C}}]3BaF2{}+2Am}}\\{\ce {PuF4{}+2Ba->[{\ce {1200^{\circ }C}}]2BaF2{}+Pu}}\\{\ce {UF4{}+2Mg->[{\ce {>500^{\circ }C}}]U{}+2MgF2}}\\{}\end{array}}}$

Among the actinides, thorium and uranium are the easiest to isolate. Thorium is extracted mostly from monazite: thorium pyrophosphate (ThP₂O₇) is reacted with nitric acid, and the produced thorium nitrate treated with tributyl phosphate. Rare-earth impurities are separated by increasing the pH in sulfate solution.

In another extraction method, monazite is decomposed with a 45% aqueous solution of sodium hydroxide at 140 °C. Mixed metal hydroxides are extracted first, filtered at 80 °C, washed with water and dissolved with concentrated hydrochloric acid. Next, the acidic solution is neutralized with hydroxides to pH = 5.8 that results in precipitation of thorium hydroxide (Th(OH)₄) contaminated with ~3% of rare-earth hydroxides; the rest of rare-earth hydroxides remains in solution. Thorium hydroxide is dissolved in an inorganic acid and then purified from the rare earth elements. An efficient method is the dissolution of thorium hydroxide in nitric acid, because the resulting solution can be purified by extraction with organic solvents:

Separation of uranium and plutonium from nuclear fuel

Th(OH)₄ + 4 HNO₃ → Th(NO₃)₄ + 4 H₂O

Metallic thorium is separated from the anhydrous oxide, chloride or fluoride by reacting it with calcium in an inert atmosphere:

ThO₂ + 2 Ca → 2 CaO + Th

Sometimes thorium is extracted by electrolysis of a fluoride in a mixture of sodium and potassium chloride at 700–800 °C in a graphite crucible. Highly pure thorium can be extracted from its iodide with the crystal bar process.

Uranium is extracted from its ores in various ways. In one method, the ore is burned and then reacted with nitric acid to convert uranium into a dissolved state. Treating the solution with a solution of tributyl phosphate (TBP) in kerosene transforms uranium into an organic form UO₂(NO₃)₂(TBP)₂. The insoluble impurities are filtered and the uranium is extracted by reaction with hydroxides as (NH₄)₂U₂O₇ or with hydrogen peroxide as UO₄·2H₂O.

When the uranium ore is rich in such minerals as dolomite, magnesite, etc., those minerals consume much acid. In this case, the carbonate method is used for uranium extraction. Its main component is an aqueous solution of sodium carbonate, which converts uranium into a complex [UO₂(CO₃)₃]⁴⁻, which is stable in aqueous solutions at low concentrations of hydroxide ions. The advantages of the sodium carbonate method are that the chemicals have low corrosivity (compared to nitrates) and that most non-uranium metals precipitate from the solution. The disadvantage is that tetravalent uranium compounds precipitate as well. Therefore, the uranium ore is treated with sodium carbonate at elevated temperature and under oxygen pressure:

2 UO₂ + O₂ + 6 CO²⁻
₃ → 2 [UO₂(CO₃)₃]⁴⁻

This equation suggests that the best solvent for the uranium carbonate processing is a mixture of carbonate with bicarbonate. At high pH, this results in precipitation of diuranate, which is treated with hydrogen in the presence of nickel yielding an insoluble uranium tetracarbonate.

Another separation method uses polymeric resins as a polyelectrolyte. Ion exchange processes in the resins result in separation of uranium. Uranium from resins is washed with a solution of ammonium nitrate or nitric acid that yields uranyl nitrate, UO₂(NO₃)₂·6H₂O. When heated, it turns into UO₃, which is converted to UO₂ with hydrogen:

UO₃ + H₂ → UO₂ + H₂O

Reacting uranium dioxide with hydrofluoric acid changes it to uranium tetrafluoride, which yields uranium metal upon reaction with magnesium metal:

4 HF + UO₂ → UF₄ + 2 H₂O

To extract plutonium, neutron-irradiated uranium is dissolved in nitric acid, and a reducing agent (FeSO₄, or H₂O₂) is added to the resulting solution. This addition changes the oxidation state of plutonium from +6 to +4, while uranium remains in the form of uranyl nitrate (UO₂(NO₃)₂). The solution is treated with a reducing agent and neutralized with ammonium carbonate to pH = 8 that results in precipitation of Pu⁴⁺ compounds.

In another method, Pu⁴⁺ and UO²⁺
₂ are first extracted with tributyl phosphate, then reacted with hydrazine washing out the recovered plutonium.

The major difficulty in separation of actinium is the similarity of its properties with those of lanthanum. Thus actinium is either synthesized in nuclear reactions from isotopes of radium or separated using ion-exchange procedures.

Properties

Actinides have similar properties to lanthanides. The 6d and 7s electronic shells are filled in actinium and thorium, and the 5f shell is being filled with further increase in atomic number; the 4f shell is filled in the lanthanides. The first experimental evidence for the filling of the 5f shell in actinides was obtained by McMillan and Abelson in 1940. As in lanthanides (see lanthanide contraction), the ionic radius of actinides monotonically decreases with atomic number.

Physical properties

Metallic and ionic radii of actinides

A pellet of ²³⁸PuO₂ to be used in a radioisotope thermoelectric generator for either the Cassini or Galileo mission. The pellet produces 62 watts of heat and glows because of the heat generated by the radioactive decay (primarily α). Photo is taken after insulating the pellet under a graphite blanket for minutes and removing the blanket.

 

Californium

 

Actinides are typical metals. All of them are soft and have a silvery color (but tarnish in air), relatively high density and plasticity. Some of them can be cut with a knife. Their electrical resistivity varies between 15 and 150 µOhm·cm. The hardness of thorium is similar to that of soft steel, so heated pure thorium can be rolled in sheets and pulled into wire. Thorium is nearly half as dense as uranium and plutonium, but is harder than either of them. All actinides are radioactive, paramagnetic, and, with the exception of actinium, have several crystalline phases: plutonium has seven, and uranium, neptunium and californium three. The crystal structures of protactinium, uranium, neptunium and plutonium do not have clear analogs among the lanthanides and are more similar to those of the 3d-transition metals.

All actinides are pyrophoric, especially when finely divided, that is, they spontaneously ignite upon reaction with air. The melting point of actinides does not have a clear dependence on the number of f-electrons. The unusually low melting point of neptunium and plutonium (~640 °C) is explained by hybridization of 5f and 6d orbitals and the formation of directional bonds in these metals.

Chemical properties

Like the lanthanides, all actinides are highly reactive with halogens and chalcogens; however, the actinides react more easily. Actinides, especially those with a small number of 5f-electrons, are prone to hybridization. This is explained by the similarity of the electron energies at the 5f, 7s and 6d shells. Most actinides exhibit a larger variety of valence states, and the most stable are +6 for uranium, +5 for protactinium and neptunium, +4 for thorium and plutonium and +3 for actinium and other actinides.

Chemically, actinium is similar to lanthanum, which is explained by their similar ionic radii and electronic structure. Like lanthanum, actinium almost always has an oxidation state of +3 in compounds, but it is less reactive and has more pronounced basic properties. Among other trivalent actinides Ac³⁺ is least acidic, i.e. has the weakest tendency to hydrolyze in aqueous solutions.

Thorium is rather active chemically. Owing to lack of electrons on 6d and 5f orbitals, the tetravalent thorium compounds are colorless. At pH < 3, the solutions of thorium salts are dominated by the cations [Th(H₂O)₈]⁴⁺. The Th⁴⁺ ion is relatively large, and depending on the coordination number can have a radius between 0.95 and 1.14 Å. As a result, thorium salts have a weak tendency to hydrolyse. The distinctive ability of thorium salts is their high solubility, not only in water, but also in polar organic solvents.

Protactinium exhibits two valence states; the +5 is stable, and the +4 state easily oxidizes to protactinium(V). Thus tetravalent protactinium in solutions is obtained by the action of strong reducing agents in a hydrogen atmosphere. Tetravalent protactinium is chemically similar to uranium(IV) and thorium(IV). Fluorides, phosphates, hypophosphate, iodate and phenylarsonates of protactinium(IV) are insoluble in water and dilute acids. Protactinium forms soluble carbonates. The hydrolytic properties of pentavalent protactinium are close to those of tantalum(V) and niobium(V). The complex chemical behavior of protactinium is a consequence of the start of the filling of the 5f shell in this element.

Uranium has a valence from 3 to 6, the last being most stable. In the hexavalent state, uranium is very similar to the group 6 elements. Many compounds of uranium(IV) and uranium(VI) are non-stoichiometric, i.e. have variable composition. For example, the actual chemical formula of uranium dioxide is UO_2+x, where x varies between −0.4 and 0.32. Uranium(VI) compounds are weak oxidants. Most of them contain the linear "uranyl" group, UO²⁺
₂. Between 4 and 6 ligands can be accommodated in an equatorial plane perpendicular to the uranyl group. The uranyl group acts as a hard acid and forms stronger complexes with oxygen-donor ligands than with nitrogen-donor ligands. NpO²⁺
₂ and PuO²⁺
₂ are also the common form of Np and Pu in the +6 oxidation state. Uranium(IV) compounds exhibit reducing properties, e.g., they are easily oxidized by atmospheric oxygen. Uranium(III) is a very strong reducing agent. Owing to the presence of d-shell, uranium (as well as many other actinides) forms organometallic compounds, such as U^III(C₅H₅)₃ and U^IV(C₅H₅)₄.

Neptunium has valence states from 3 to 7, which can be simultaneously observed in solutions. The most stable state in solution is +5, but the valence +4 is preferred in solid neptunium compounds. Neptunium metal is very reactive. Ions of neptunium are prone to hydrolysis and formation of coordination compounds.

Plutonium also exhibits valence states between 3 and 7 inclusive, and thus is chemically similar to neptunium and uranium. It is highly reactive, and quickly forms an oxide film in air. Plutonium reacts with hydrogen even at temperatures as low as 25–50 °C; it also easily forms halides and intermetallic compounds. Hydrolysis reactions of plutonium ions of different oxidation states are quite diverse. Plutonium(V) can enter polymerization reactions.

The largest chemical diversity among actinides is observed in americium, which can have valence between 2 and 6. Divalent americium is obtained only in dry compounds and non-aqueous solutions (acetonitrile). Oxidation states +3, +5 and +6 are typical for aqueous solutions, but also in the solid state. Tetravalent americium forms stable solid compounds (dioxide, fluoride and hydroxide) as well as complexes in aqueous solutions. It was reported that in alkaline solution americium can be oxidized to the heptavalent state, but these data proved erroneous. The most stable valence of americium is 3 in the aqueous solutions and 3 or 4 in solid compounds.

Valence 3 is dominant in all subsequent elements up to lawrencium (with the exception of nobelium). Curium can be tetravalent in solids (fluoride, dioxide). Berkelium, along with a valence of +3, also shows the valence of +4, more stable than that of curium; the valence 4 is observed in solid fluoride and dioxide. The stability of Bk⁴⁺ in aqueous solution is close to that of Ce⁴⁺.^[92] Only valence 3 was observed for californium, einsteinium and fermium. The divalent state is proven for mendelevium and nobelium, and in nobelium it is more stable than the trivalent state. Lawrencium shows valence 3 both in solutions and solids.

The redox potential ${\displaystyle {\ce {{\mathit {E}}_{\frac {M^{4}+}{AnO2^{2}+}}}}}$ increases from −0.32 V in uranium, through 0.34 V (Np) and 1.04 V (Pu) to 1.34 V in americium revealing the increasing reduction ability of the An⁴⁺ ion from americium to uranium. All actinides form AnH₃ hydrides of black color with salt-like properties. Actinides also produce carbides with the general formula of AnC or AnC₂ (U₂C₃ for uranium) as well as sulfides An₂S₃ and AnS₂.

• 

  Uranyl nitrate (UO₂(NO₃)₂) 
  
  
• 

  Aqueous solutions of uranium III, IV, V, VI salts 
  
  
• 

  Aqueous solutions of neptunium III, IV, V, VI, VII salts 
  
  
• 

  Aqueous solutions of plutonium III, IV, V, VI, VII salts
   
  
• 

  Uranium tetrachloride
   
  
• 

  Uranium hexafluoride
   
  
• 

  U₃O₈ (yellowcake)
  

Compounds

Oxides and hydroxides

Some actinides can exist in several oxide forms such as An₂O₃, AnO₂, An₂O₅ and AnO₃. For all actinides, oxides AnO₃ are amphoteric and An₂O₃, AnO₂ and An₂O₅ are basic, they easily react with water, forming bases:

An₂O₃ + 3 H₂O → 2 An(OH)₃.

These bases are poorly soluble in water and by their activity are close to the hydroxides of rare-earth metals. Np(OH)₃ has not yet been synthesized, Pu(OH)₃ has a blue color while Am(OH)₃ is pink and curium hydroxide Cm(OH)₃ is colorless. Bk(OH)₃ and Cf(OH)₃ are also known, as are tetravalent hydroxides for Np, Pu and Am and pentavalent for Np and Am.

The strongest base is of actinium. All compounds of actinium are colorless, except for black actinium sulfide (Ac₂S₃). Dioxides of tetravalent actinides crystallize in the cubic system, same as in calcium fluoride. 

Thorium reacting with oxygen exclusively forms the dioxide:

${\displaystyle {\ce {Th{}+O2->[{\ce {1000^{\circ }C}}]\overbrace {ThO2} ^{Thorium~dioxide}}}}$

Thorium dioxide is a refractory material with the highest melting point among any known oxide (3390 °C). Adding 0.8–1% ThO₂ to tungsten stabilizes its structure, so the doped filaments have better mechanical stability to vibrations. To dissolve ThO₂ in acids, it is heated to 500–600 °C; heating above 600 °C produces a very resistant to acids and other reagents form of ThO₂. Small addition of fluoride ions catalyses dissolution of thorium dioxide in acids. 

Two protactinium oxides have been obtained: PaO₂ (black) and Pa₂O₅ (white); the former is isomorphic with ThO₂ and the latter is easier to obtain. Both oxides are basic, and Pa(OH)₅ is a weak, poorly soluble base.

Decomposition of certain salts of uranium, for example UO₂(NO₃)·6H₂O in air at 400 °C, yields orange or yellow UO₃. This oxide is amphoteric and forms several hydroxides, the most stable being uranyl hydroxide UO₂(OH)₂. Reaction of uranium(VI) oxide with hydrogen results in uranium dioxide, which is similar in its properties with ThO₂. This oxide is also basic and corresponds to the uranium hydroxide (U(OH)₄).

Plutonium, neptunium and americium form two basic oxides: An₂O₃ and AnO₂. Neptunium trioxide is unstable; thus, only Np₃O₈ could be obtained so far. However, the oxides of plutonium and neptunium with the chemical formula AnO₂ and An₂O₃ are well characterized.

Salts

Einsteinium triiodide glowing in the dark

Actinides easily react with halogens forming salts with the formulas MX₃ and MX₄ (X = halogen). So the first berkelium compound, BkCl₃, was synthesized in 1962 with an amount of 3 nanograms. Like the halogens of rare earth elements, actinide chlorides, bromides, and iodides are water-soluble, and fluorides are insoluble. Uranium easily yields a colorless hexafluoride, which sublimates at a temperature of 56.5 °C; because of its volatility, it is used in the separation of uranium isotopes with gas centrifuge or gaseous diffusion. Actinide hexafluorides have properties close to anhydrides. They are very sensitive to moisture and hydrolyze forming AnO₂F₂. The pentachloride and black hexachloride of uranium were synthesized, but they are both unstable.

Action of acids on actinides yields salts, and if the acids are non-oxidizing then the actinide in the salt is in low-valence state:

U + 2H₂SO₄ → U(SO₄)₂ + 2H₂

2Pu + 6HCl → 2PuCl₃ + 3H₂

However, in these reactions the regenerating hydrogen can react with the metal, forming the corresponding hydride. Uranium reacts with acids and water much more easily than thorium.

Actinide salts can also be obtained by dissolving the corresponding hydroxides in acids. Nitrates, chlorides, sulfates and perchlorates of actinides are water-soluble. When crystallizing from aqueous solutions, these salts forming a hydrates, such as Th(NO₃)₄·6H₂O, Th(SO₄)₂·9H₂O and Pu₂(SO₄)₃·7H₂O. Salts of high-valence actinides easily hydrolyze. So, colorless sulfate, chloride, perchlorate and nitrate of thorium transform into basic salts with formulas Th(OH)₂SO₄ and Th(OH)₃NO₃. The solubility and insolubility of trivalent and tetravalent actinides is like that of lanthanide salts. So phosphates, fluorides, oxalates, iodates and carbonates of actinides are weakly soluble in water; they precipitate as hydrates, such as ThF₄·3H₂O and Th(CrO₄)₂·3H₂O.

Actinides with oxidation state +6, except for the AnO₂²⁺-type cations, form [AnO₄]²⁻, [An₂O₇]²⁻ and other complex anions. For example, uranium, neptunium and plutonium form salts of the Na₂UO₄ (uranate) and (NH₄)₂U₂O₇ (diuranate) types. In comparison with lanthanides, actinides more easily form coordination compounds, and this ability increases with the actinide valence. Trivalent actinides do not form fluoride coordination compounds, whereas tetravalent thorium forms K₂ThF₆, KThF₅, and even K₅ThF₉ complexes. Thorium also forms the corresponding sulfates (for example Na₂SO₄·Th(SO₄)₂·5H₂O), nitrates and thiocyanates. Salts with the general formula An₂Th(NO₃)₆·nH₂O are of coordination nature, with the coordination number of thorium equal to 12. Even easier is to produce complex salts of pentavalent and hexavalent actinides. The most stable coordination compounds of actinides – tetravalent thorium and uranium – are obtained in reactions with diketones, e.g. acetylacetone.

Applications

Interior of a smoke detector containing americium-241.

 

While actinides have some established daily-life applications, such as in smoke detectors (americium) and gas mantles (thorium), they are mostly used in nuclear weapons and use as a fuel in nuclear reactors. The last two areas exploit the property of actinides to release enormous energy in nuclear reactions, which under certain conditions may become self-sustaining chain reaction. 

Self-illumination of a nuclear reactor by Cherenkov radiation.

 

The most important isotope for nuclear power applications is uranium-235. It is used in the thermal reactor, and its concentration in natural uranium does not exceed 0.72%. This isotope strongly absorbs thermal neutrons releasing much energy. One fission act of 1 gram of ²³⁵U converts into about 1 MW·day. Of importance, is that ²³⁵
₉₂U
emits more neutrons than it absorbs; upon reaching the critical mass, ²³⁵
₉₂U
enters into a self-sustaining chain reaction. Typically, uranium nucleus is divided into two fragments with the release of 2–3 neutrons, for example:

²³⁵
₉₂U
+ ¹
₀n
⟶ ¹¹⁵
₄₅Rh
+ ¹¹⁸
₄₇Ag
+ 3¹
₀n

Other promising actinide isotopes for nuclear power are thorium-232 and its product from the thorium fuel cycle, uranium-233. 

Nuclear reactor

The core of most Generation II nuclear reactors contains a set of hollow metal rods, usually made of zirconium alloys, filled with solid nuclear fuel pellets – mostly oxide, carbide, nitride or monosulfide of uranium, plutonium or thorium, or their mixture (the so-called MOX fuel). The most common fuel is oxide of uranium-235.    Fast neutrons are slowed by moderators, which contain water, carbon, deuterium, or beryllium, as thermal neutrons to increase the efficiency of their interaction with uranium-235. The rate of nuclear reaction is controlled by introducing additional rods made of boron or cadmium or a liquid absorbent, usually boric acid. Reactors for plutonium production are called breeder reactor or breeders; they have a different design and use fast neutrons.

Emission of neutrons during the fission of uranium is important not only for maintaining the nuclear chain reaction, but also for the synthesis of the heavier actinides. Uranium-239 converts via β-decay into plutonium-239, which, like uranium-235, is capable of spontaneous fission. The world's first nuclear reactors were built not for energy, but for producing plutonium-239 for nuclear weapons.

About half of the produced thorium is used as the light-emitting material of gas mantles. Thorium is also added into multicomponent alloys of magnesium and zinc. So the Mg-Th alloys are light and strong, but also have high melting point and ductility and thus are widely used in the aviation industry and in the production of missiles. Thorium also has good electron emission properties, with long lifetime and low potential barrier for the emission. The relative content of thorium and uranium isotopes is widely used to estimate the age of various objects, including stars (see radiometric dating).

The major application of plutonium has been in nuclear weapons, where the isotope plutonium-239 was a key component due to its ease of fission and availability. Plutonium-based designs allow reducing the critical mass to about a third of that for uranium-235. The "Fat Man"-type plutonium bombs produced during the Manhattan Project used explosive compression of plutonium to obtain significantly higher densities than normal, combined with a central neutron source to begin the reaction and increase efficiency. Thus only 6.2 kg of plutonium was needed for an explosive yield equivalent to 20 kilotons of TNT. Hypothetically, as little as 4 kg of plutonium—and maybe even less—could be used to make a single atomic bomb using very sophisticated assembly designs.

Plutonium-238 is potentially more efficient isotope for nuclear reactors, since it has smaller critical mass than uranium-235, but it continues to release much thermal energy (0.56 W/g) by decay even when the fission chain reaction is stopped by control rods. Its application is limited by the high price (about US$1000/g). This isotope has been used in thermopiles and water distillation systems of some space satellites and stations. So Galileo and Apollo spacecraft (e.g. Apollo 14) had heaters powered by kilogram quantities of plutonium-238 oxide; this heat is also transformed into electricity with thermopiles. The decay of plutonium-238 produces relatively harmless alpha particles and is not accompanied by gamma-irradiation. Therefore, this isotope (~160 mg) is used as the energy source in heart pacemakers where it lasts about 5 times longer than conventional batteries.

Actinium-227 is used as a neutron source. Its high specific energy (14.5 W/g) and the possibility of obtaining significant quantities of thermally stable compounds are attractive for use in long-lasting thermoelectric generators for remote use. ²²⁸Ac is used as an indicator of radioactivity in chemical research, as it emits high-energy electrons (2.18 MeV) that can be easily detected. ²²⁸Ac-²²⁸Ra mixtures are widely used as an intense gamma-source in industry and medicine.

Development of self-glowing actinide-doped materials with durable crystalline matrices is a new area of actinide utilization as the addition of alpha-emitting radionuclides to some glasses and crystals may confer luminescence.

Toxicity

Schematic illustration of penetration of radiation through sheets of paper, aluminium and lead brick

 

Periodic table with elements colored according to the half-life of their most stable isotope.

  Elements which contain at least one stable isotope.

  Slightly radioactive elements: the most stable isotope is very long-lived, with a half-life of over two million years.

  Significantly radioactive elements: the most stable isotope has half-life between 800 and 34,000 years.

  Radioactive elements: the most stable isotope has half-life between one day and 130 years.

  Highly radioactive elements: the most stable isotope has half-life between several minutes and one day.

  Extremely radioactive elements: the most stable isotope has half-life less than several minutes.

Radioactive substances can harm human health via (i) local skin contamination, (ii) internal exposure due to ingestion of radioactive isotopes, and (iii) external overexposure by β-activity and γ-radiation. Together with radium and transuranium elements, actinium is one of the most dangerous radioactive poisons with high specific α-activity. The most important feature of actinium is its ability to accumulate and remain in the surface layer of skeletons. At the initial stage of poisoning, actinium accumulates in the liver. Another danger of actinium is that it undergoes radioactive decay faster than being excreted. Adsorption from the digestive tract is much smaller (~0.05%) for actinium than radium.

Protactinium in the body tends to accumulate in the kidneys and bones. The maximum safe dose of protactinium in the human body is 0.03 µCi that corresponds to 0.5 micrograms of ²³¹Pa. This isotope, which might be present in the air as aerosol, is 2.5×10⁸ times more toxic than hydrocyanic acid.

Plutonium, when entering the body through air, food or blood (e.g. a wound), mostly settles in the lungs, liver and bones with only about 10% going to other organs, and remains there for decades. The long residence time of plutonium in the body is partly explained by its poor solubility in water. Some isotopes of plutonium emit ionizing α-radiation, which damages the surrounding cells. The median lethal dose (LD₅₀) for 30 days in dogs after intravenous injection of plutonium is 0.32 milligram per kg of body mass, and thus the lethal dose for humans is approximately 22 mg for a person weighing 70 kg; the amount for respiratory exposure should be approximately four times greater. Another estimate assumes that plutonium is 50 times less toxic than radium, and thus permissible content of plutonium in the body should be 5 µg or 0.3 µCi. Such amount is nearly invisible in under microscope. After trials on animals, this maximum permissible dose was reduced to 0.65 µg or 0.04 µCi. Studies on animals also revealed that the most dangerous plutonium exposure route is through inhalation, after which 5–25% of inhaled substances is retained in the body. Depending on the particle size and solubility of the plutonium compounds, plutonium is localized either in the lungs or in the lymphatic system, or is absorbed in the blood and then transported to the liver and bones. Contamination via food is the least likely way. In this case, only about 0.05% of soluble 0.01% insoluble compounds of plutonium absorbs into blood, and the rest is excreted. Exposure of damaged skin to plutonium would retain nearly 100% of it.

Using actinides in nuclear fuel, sealed radioactive sources or advanced materials such as self-glowing crystals has many potential benefits. However, a serious concern is the extremely high radiotoxicity of actinides and their migration in the environment. Use of chemically unstable forms of actinides in MOX and sealed radioactive sources is not appropriate by modern safety standards. There is a challenge to develop stable and durable actinide-bearing materials, which provide safe storage, use and final disposal. A key need is application of actinide solid solutions in durable crystalline host phases.

Mental health professional

From Wikipedia, the free encyclopedia

A mental health professional is a health care practitioner or community services provider who offers services for the purpose of improving an individual's mental health or to treat mental disorders. This broad category was developed as a name for community personnel who worked in the new community mental health agencies begun in the 1970s to assist individuals moving from state hospitals, to prevent admissions, and to provide support in homes, jobs, education and community. These individuals (i.e., state office personnel, private sector personnel, and non-profit, now voluntary sector personnel) were the forefront brigade to develop the community programs, which today may be referred to by names such as supported housing, psychiatric rehabilitation, supported or transitional employment, sheltered workshops, supported education, daily living skills, affirmative industries, dual diagnosis treatment, individual and family psychoeducation, adult day care, foster care, family services and mental health counseling.

The category seldom includes psychiatrists (DO or MD) who remained institutional based and guarded the admissions procedures at institutionalization (both private and state specialty hospitals). However, in 2013, psychiatrists also are working in clinical fields with psychologists including in sociobehavioral, neurological, person-centered and clinical approaches (often office-based), and studies of the "brain disease" (which came from the community fields and community management and are taught at the MA to PhD level in education). For example, Nat Raskin (at Northwestern University Medical School) who worked with the illustrious Carl Rogers, published on person-centered approaches and therapy in 2004. The term counselors often refers to office-based professionals who offer therapy sessions to their clients, operated by organizations such as pastoral counseling (which may or may not work with long term services clients) and family counselors. Mental health counselors may refer to counselors working in residential services in the field of mental health in community programs.

As community professionals

As Dr. William Anthony, father of psychiatric rehabilitation, described, psychiatric nurses (RNMH, RMN, CPN), clinical psychologists (PsyD or PhD), clinical social workers (MSW or MSSW), mental health counselors (MA or MS), professional counselors, pharmacists, as well as many other professionals are often educated in "psychiatric fields" or conversely, educated in a generic community approach (e.v fdcgaxbgcg., human services programs, or health and human services in 2013). However, histxt primary concern is education that leads to a willingness to work with "long-term services and supports" community support in the community to lead to better life quality for the individual, the families and the community. 

The community support framework in the US of the 1970s is taken-for-granted as the base for new treatment developments (e.g., eating disorders, drug addiction programs) which tend to be free standing clinics for specific "disorders". Typically, the term "mental health professional" does not refer to other categorical disability areas, such as intellectual and developmental disability (which trains its own professionals and maintains its own journals, and US state systems and institutions). Psychiatric rehabilitation has also been reintroduced into the transfer to behavioral health care systems.

As certified and licensed (across institutions and communities)

These professionals often deal with the same illnesses, disorders, conditions, and issues (though may separate on site locations, such as hospital or community for the same clientele); however, their scope of practice differs and more particularly, their positions and roles in the fields of mental health services and systems. The most significant difference between mental health professionals are the laws regarding required education and training across the various professions. However, the most significant change has been the Supreme Court Olmstead Decision on the most integrated setting which should further reduce state hospital utilization; yet with new professionals seeking right for community treatment orders and rights to administer medications (original community programs, residents taught to self-administer medications, 1970s). 

In 2013, new mental health practitioners are licensed or certified in the community (e.g., PhD, education in private clinical practice) by states, degrees and certifications are offered in fields such as psychiatric rehabilitation (MS, PhD), BA psychology (liberal arts, experimental/clinical/existential/community)to MA licensing is now more popular, BA (to PhD) mid-level program management, qualified civil service professionals, and social workers remain the mainstay of community admissions procedures (licensed by state, often generic training) in the US. Surprisingly, state direction has moved from psychiatry or clinical psychology to community leadership and professionalization of community services management.

Entry level recruitment and training remain a primary concern (since the 1970s, then often competing with fast food positions), and the US Direct Support Workforce includes an emphasis on also training of psychiatric aides, behavioral aides, and addictions aides to work in homes and communities. The Centers for Medicaid and Medicare have new provisions for "self-direction" in services and new options are in place for individual plans for better life outcomes. Community programs are increasingly using health care financing, such as Medicaid, and Mental Health Parity is now law in the US.

Professional distinctions

Comparison of American mental health professionals

	Degree	Common licenses	Prescription privilege	Average income (US$)
Psychiatrist	MD/DO	Psychiatrist	Yes	$200,000
Psychiatric Rehabilitation Counselor	Master of Rehabilitation Sciences PhD Doctor of Philosophy	Similar to Related Personnel (Cognitive Sciences), Rehabilitation Counselors	No	$50,000
Clinical Psychologist	PhD/PsyD	Psychologist	No	$85,000
School Psychologist	Doctoral level PhD/EdD/PsyD Post-master's terminal degree (not doctoral level) EdS Doctoral degrees, PhD Inclusion educators Master's level MA/MS	Certified School Psychology, National Certified School Psychologist	No	$78,000
Counselor/Psychotherapist (Doctorate)	PhD/EdD/DMFT	Psychologist	No	$45,000-$75,000
Counselor/Psychotherapist/Rehabilitation/Mental Health (Master's)	MA/MS/MC plus two to three years of post-master's supervised clinical experience	Mental health counselors/LMFT/LCPC/LPC/LPA/LMHC	No	$49,000
Clinical or Psychiatric Social Worker	MSW/DSW/PhD plus two to three years of post-master's supervised clinical experience	LCSW/LMSW/LSW	No	$50,700
Social Worker (agency based master's/doctoral levels)	MSW/DSW/PhD	LMSW/GSW/LSW	No	$46,170-$70,000
Social Worker (bachelor or diploma level)	BSW or SSW	RSW, RSSW, SWA, social work assistant	No	$35,000
Occupational therapist (Doctorate/master level)	MOT, MSOT, OTD, ScD, PhD	Related supervised community personnel in physical, speech and communication, OTR, COTA	No	$45,000-69,630
Licensed behavior analysts Licensed dual inclusion educators (Doctorate/master level) Behavior analyst, substance abuse and behavioral disorders, "inclusion educator"	PhD/EdD/MS/MEd/MA	LBA/LBS/BCBA/BCBA-D Dual Licensed inclusion educator	No	$60,000, $80,000 up for inclusion educator
Psychiatric and mental health nurse practitioner	MSN/DNP/PhD	PMHNP-BC	Yes	$135,000
Physician assistant	MPAS/MHS/MMS/DScPA	PA/PA-C/APA-C/RPA/RPA-C	Yes	$80,356
Expressive Therapist/Creative Arts Therapist	MA	ATR-BC/MT-BC/BC-DMT/RDT/CPT	No	$30,000-70,000

Exceptions include New Mexico, Louisiana, and limited rights in Indiana and Guam.

Additional Sources/Clarifications: now operating programs with health care financing in the community. Higher paid medical and health services manager which only operates facilities, considered to be easier than dispersed services management in the community for long-term services and supports (LTSS) often by disability NGOs or state governments (civil service). 

The Mental Health Professional Class has often not been included in these occupational schemas in which Occupational Handbooks often separate Human Service Management Classes and Professional Classes from the term Health Care. Common salary ranges are in the $30,000-40,000 for the higher professional at the small community agency. The professionals are considered to be part of the federal Health and Human Services professions. Their responsibilities at the high gates are greater than a psychiatrist assistant who is responsible, to date, only to the psychiatrist. The occupational therapist is considered as an aide to that professional level, as is a behavioral specialist as hired by the agency and the nurse practitioner. Mental health workers in the community (E.g., workers with the homeless, in homes, families and jails, community programs such as group homes) may still be termed Community Support Workers with diverse degrees and qualifications [US Direct Support Professional Workforce]. 

Children's professionals in the field of mental health include inclusion educators (over $80,000 at the PhD levels) who have been cross-educated in the fields, and "residential treatment" personnel which need dual reviews of credentials (child care, family support, child welfare, independent living, special education and home life, residential skills training programs).

Treatment diversity and community mental health

Mental health professionals exist to improve the mental health of individuals, couples, families and the community-at-large. [In this generic use, mental health is available to the entire population, similar to the use by mental health associations.] Because mental health covers a wide range of elements, the scope of practice greatly varies between professionals. Some professionals may enhance relationships while others treat specific mental disorders and illness; still others work on population-based health promotion or prevention activities. Often, as with the case of psychiatrists and psychologists, the scope of practice may overlap often due to common hiring and promotion practices by employers.

As indicated earlier, community mental health professionals have been involved in beginning and operating community programs which include ongoing efforts to improve life outcomes, originally through long term services and supports (LTSS). Termed functional or competency-based programs, these service also stressed decision making and self-determination or empowerment as critical aspects. Community mental health professionals may also serve children which have different needs, as do families, including family therapy, financial assistance and support services. Community mental health professionals serve people of all ages from young children with autism, to children with emotional (or behavioral) needs, to grandma who has Alzheimer's or dementia and is living at home after dad passes away. 

Most qualified mental health professionals will refer a patient or client to another professional if the specific type of treatment needed is outside of their scope of practice. The main community concern is "zero rejection" from community services for individuals who have been termed "hard to serve" in the population ["schizophrenia"] ["dual diagnosis"] or who have additional needs such as mobility and sensory impairments. Additionally, many mental health professionals may sometimes work together using a variety of treatment options such as concurrent psychiatric medication and psychotherapy and supported housing. Additionally, specific mental health professionals may be utilized based upon their cultural and religious background or experience, as part of a theory of both alternative medicines and of the nature of helping and ethnicity.

Primary care providers, such as internists, pediatricians, and family physicians, may provide initial components of mental health diagnosis and treatment for children and adults; however, family physicians in some states refuse to even prescribe a psychotropic medication deferring to separately funded "medication management" services. Community programs in the categorical field of mental health were designed (1970s) to have a personal family physician for every client in their programs, except for institutional settings and nursing facilities which have only one or two for a large facility (1980, 2013). 

In particular, family physicians are trained during residency in interviewing and diagnostic skills, and may be quite skilled in managing conditions such as ADHD in children and depression in adults. Likewise, many (but not all) pediatricians may be taught the basic components of ADHD diagnosis and treatment during residency. In many other circumstances, primary care physicians may receive additional training and experience in mental health diagnosis and treatment during their practice years.

Relative effectiveness

Both primary care physicians (GP's) and psychiatrists are just as effective (in terms of remission rates) for the treatment of depression. However, treatment resistant depression, suicidal, homicidal ideation, psychosis and catatonia should be handled by mental health specialists. Treatment resistant depression (or treatment refractory depression) refers to depression which remains at large after at least two antidepressant medications have been trailed on their own.

Peer workers

Some think that mental health professionals are less credible when they have personal experience of mental health. In fact, the mental health sector goes out of its way to hire people with mental illness experience. Those in the mental health workforce with a personal experience of mental health are referred to as ‘peer (support) workers’. The balance of evidence appears to favour their employment: Randomised controlled trials consistently demonstrate peer staff produce outcomes on par with non-peer staff in ancillary roles, but they actually perform better in reducing hospitalisation rates, engaging clients who are difficult to reach, and cutting substance use. There is research that indicates peer workers cultivate a perception among service users that the service is more responsive to non-treatment things, increases their hope, family satisfaction, self-esteem and community belonging

Psychiatrists and clinical psychology

Psychiatrists are physicians and one of the few professionals in the mental health industry who specialize and are certified in treating mental illness using the biomedical approach to mental disorders including the use of medications. However, biological, genetic and social processes as part of premedicine have been the basis of education in fields such as BA psychology since the 1970s, and in 2013, such academic degrees also may include extensive work on the status of brain, DNA research and its applications.[See, Cornell University, Liberal Arts, College of Arts and Sciences, endowed institution in the US] Clinical psychologists were hired by states and served in institutions in the US, and were involved in the transition to community systems.

Psychiatrists may also go through significant training to conduct psychotherapy and cognitive behavioral therapy; however psychologists and clinical psychologists specialize in the research and clinical application of these techniques. The amount of training a psychiatrist holds in providing these types of therapies varies from program to program and also differs greatly based upon region. [Cognitive therapy also stems from cognitive rehabilitation techniques, and may involve long-term community clients with brain injuries seeking jobs, education and community housing.] In the 1970s, psychiatrists were considered to be hospital-based, assessment, and clinical education personnel which were not involved in establishing community programs. They were often criticized for serving the "young, white, urban, professional" as their main clientele groups, though piloting services such as hospital social day care which are now in senior programs.

Specialties of psychiatrists

As part of their evaluation of the patient, psychiatrists are one of only a few mental health professionals who may conduct physical examinations, order and interpret laboratory tests and EEGs, and may order brain imaging studies such as CT or CAT, MRI, and PET scanning. A medical professional must evaluate the patient for any medical problems or diseases that may be the cause of the mental illness.

Historically psychiatrists have been the only mental health professional with the power to prescribe medication to treat specific types of mental illness. Currently, Physician Assistants responsible to the psychiatrist (in lieu of and supervised)and advanced practice psychiatric nurses may prescribe medications, including psychiatric medications. Clinical psychologists have gained the ability to prescribe psychiatric medications on a limited basis in a few U.S. states after completing additional training and passing an examination.

Educational requirements for psychiatrists

Typically the requirements to become a psychiatrist are substantial but differ from country to country. In general there is an initial period of several years of academic and clinical training and supervised work in different areas of medicine, in order to become a licensed medical doctor, followed by several years of supervised work and study in psychiatry, in order to become a licensed psychiatrist.

In the United States and Canada one must first complete a Bachelor's degree. Students may typically decide any major subject of their choice, however they must enroll in specific courses, usually outlined in a pre-medical program. One must then apply to and attend 4 years of medical school in order to earn his MD or DO and to complete his medical education. Psychiatrists must then pass three successive rigorous national board exams (United States Medical Licensing Exams "USMLE", Steps 1, 2, and 3), which draws questions from all fields of medicine and surgery, before gaining an unrestricted license to practice medicine. Following this, the individual must complete a four-year residency in Psychiatry as a psychiatric resident and sit for annual national in-service exams. Psychiatry residents are required to complete at least four post-graduate months of internal medicine (pediatrics may be substituted for some or all of the internal medicine months for those planning to specialize in child and adolescent psychiatry) and two months of neurology, usually during the first year, but some programs require more. Occasionally, some prospective psychiatry residents will choose to do a transitional year internship in medicine or general surgery, in which case they may complete the two months of neurology later in their residency. After completing their training, psychiatrists take written and then oral specialty board examinations. The total amount of time required to qualify in the field of psychiatry in the United States is typically 4 to 5 years after obtaining the MD or DO (or in total 8 to 9 years minimum). Many psychiatrists pursue an additional 1–2 years in subspecialty fellowships on top of this such as child psychiatry, geriatric psychiatry, and psychosomatic medicine. 

In the United Kingdom, the Republic of Ireland, and most Commonwealth countries, the initial degree is the combined Bachelor of Medicine and Bachelor of Surgery, usually a single period of academic and clinical study lasting around five years. This degree is most often abbreviated 'MBChB', 'MB BS' or other variations, and is the equivalent of the American 'MD'. Following this the individual must complete a two-year foundation programmer that mainly consists of supervised paid work as a Foundation House Officer within different specialties of medicine. Upon completion the individual can apply for "core specialist training" in psychiatry, which mainly involves supervised paid work as a Specialty Registrar in different subspecialities of psychiatry. After three years there is an examination for Membership of the Royal College of Psychiatrists (abbreviated MRCPsych), with which an individual may then work as a "Staff grade" or "Associate Specialist" psychiatrist, or pursue an academic psychiatry route via a PhD. If, after the MRCPsych, an additional 3 years of specialization known as "advanced specialist training" are taken (again mainly paid work), and a Certificate of Completion of Training is awarded, the individual can apply for a post taking independent clinical responsibility as a "consultant" psychiatrist.

Clinical psychologist

A clinical psychologist studies and applies psychology for the purpose of understanding, preventing, and relieving psychologically-based distress or dysfunction and to promote subjective well-being and personal development. In many countries it is a regulated profession that addresses moderate to more severe or chronic psychological problems, including diagnosable mental disorders. Clinical psychology includes a wide range of practices, such as research, psychological assessment, teaching, consultation, forensic testimony, and program development and administration. Central to clinical psychology is the practice of psychotherapy, which uses a wide range of techniques to change thoughts, feelings, or behaviors in service to enhancing subjective well-being, mental health, and life functioning. Unlike other mental health professionals, psychologists are trained to conduct psychological assessment. Clinical psychologists can work with individuals, couples, children, older adults, families, small groups, and communities.

Specialties of clinical psychologists

Clinical psychologists who focus on treating mental health specialize in evaluating patients and providing psychotherapy. They do not prescribe medication as this is a role of a psychiatrist (physician who specializes in psychiatry). There are a wide variety of therapeutic techniques and perspectives that guide practitioners, although most fall into the major categories of Psychodynamic, Cognitive Behavioral, Existential-Humanistic, and Systems Therapy (e.g. family or couples therapy).

In addition to therapy, clinical psychologists are also trained to administer and interpret psychological personality tests such as the MMPI and the Rorschach inkblot test, and various standardized tests of intelligence, memory, and neuropsychological functioning. Common areas of specialization include: specific disorders (e.g. trauma), neuropsychological disorders, child and adolescent, family and relationship counseling. Internationally, psychologists are generally not granted prescription privileges. In the US, prescriptive rights have been granted to appropriately trained psychologists only in the states of New Mexico and Louisiana, with some limited prescriptive rights in Indiana and the US territory of Guam.

Educational requirements for clinical psychologists

Clinical psychologists, having completed an undergraduate degree usually in psychology or other social science, generally undergo specialist postgraduate training lasting at least two years (e.g. Australia), three years (e.g. UK), or four to six years depending how much research activity is included in the course (e.g. US). In countries where the course is of shorter duration, there may be an informal requirement for applicants to have undertaken prior work experience supervised by a clinical psychologist, and a proportion of applicants may also undertake a separate PhD research degree. 

Today, in the U.S., about half of licensed psychologists are trained in the Scientist-Practitioner Model of Clinical Psychology (PhD)—a model that emphasizes both research and clinical practice and is usually housed in universities. The other half are being trained within a Practitioner-Scholar Model of Clinical Psychology (PsyD), which focuses on practice (similar to professional degrees for medicine and law). A third training model called the Clinical Scientist Model emphasizes training in clinical psychology research. Outside of coursework, graduates of both programs generally are required to have had 2 to 3 years of supervised clinical experience, a certain amount of personal psychotherapy, and the completion of a dissertation (PhD programs usually require original quantitative empirical research, whereas the PsyD equivalent of dissertation research often consists of literature review and qualitative research, theoretical scholarship, program evaluation or development, critical literature analysis, or clinical application and analysis).

Continuing Education Requirements for Clinical Psychologists

Most states in the US require clinical psychologists to obtain a certain number of continuing education credits in order to renew their license. This was established to ensure that psychologists stay current with information and practices in their fields. The license renewal cycle varies, but renewal is generally required every two years.

The number of continuing education credits required for clinical psychologists varies between states. In Nebraska, psychologists are required to obtain 24 hours of approved continuing education credits in the 24 months before their license renewal. In California, the requirement is for 36 hours of credits. New York State does not have any continuing education requirements for license renewal at this time (2014).

Activities that count towards continuing education credits generally include completing courses, publishing research papers, teaching classes, home study, and attending workshops. Some states require that a certain number of the education credits be in ethics. Most states allow psychologists to self-report their credits but randomly audit individual psychologists to ensure compliance.

Counseling psychologist or psychotherapist

Counseling generally involves helping people with what might be considered "normal" or "moderate" psychological problems, such as the feelings of anxiety or sadness resulting from major life changes or events. As such, counseling psychologists often help people adjust to or cope with their environment or major events, although many also work with more serious problems as well.

One may practice as a counseling psychologist with a PhD or EdD, and as a counseling psychotherapist with a master's degree. Compared with clinical psychology, there are fewer counseling psychology graduate programs (which are commonly housed in departments of education), counselors tend to conduct more vocational assessment and less projective or objective assessment, and they are more likely to work in public service or university clinics (rather than hospitals or private practice). Despite these differences, there is considerable overlap between the two fields and distinctions between them continue to fade. 

Mental health counselors and residential counselors are also the name for another class of counselors or mental health professionals who may work with long-term services and supports (LTSS) clients in the community. Such counselors may be advanced or senior staff members in a community program, and may be involved in developing skill teaching, active listening (and similar psychological and educational methods), and community participation programs. They also are often skilled in on-site intervention, redirection and emergency techniques. Supervisory personnel often advance from this class of workers in community programs.

Behavior analysts and community/institutional roles

Behavior analysts are licensed in five states to provide services for clients with substance abuse, developmental disabilities, and mental illness. This profession draws on the evidence base of applied behavior analysis, behavior therapy, and the philosophy of behaviorism. Behavior analysts have at least a master's degree in behavior analysis or in a mental health related discipline as well as at least five core courses in applied behavior analysis (narrow focus in psychological education). Many behavior analysts have a doctorate. Most programs have a formalized internship program and several programs are offered online. Most practitioners have passed the examination offered by the behavior analysis certification board or the examination in clinical behavior therapy by the World Association for Behavior Analysis. The model licensing act for behavior analysts can be found at the Association for Behavior Analysis International's website.

Behavior analysts (who grew from the definition of mental health as a behavioral problem) often use community situational activities, life events, functional teaching, community "reinforcers", family and community staff as intervenors, and structured interventions as the base in which they may be called upon to provide skilled professional assistance. Approaches that are based upon person-centered approaches have been used to update the stricter, hospital based interventions used by behavior analysts for applicability to community environments Behavioral approaches have often been infused with efforts at client self-determination, have been aligned with community lifestyle planning, and have been criticized as "aversive technology" which was "outlawed" in the field of severe disabilities in the 1990s.

Certified Mental Health Professional

The Certified Mental Health Professional (CMHP) certification is designed to measure an individual’s competency in performing the following job tasks. The job tasks are a sampling of job tasks with a clinical emphasis, and represents a level of line staff in community programs reporting to a community supervisor in a small site based program. Personnel in community housing, nursing facilities, and institutional programs may be covered by these kinds of certifications.

• Maintain confidentiality of records relating to clients’ treatment (and daily affairs as desired by the person).
• Encourage clients to express their feelings, discuss what is happening in their lives, and help them to develop insight into themselves and their relationships.
• Guide clients in the development of skills and strategies for dealing with their problems (and desired life outcomes).
• Prepare and maintain all required treatment (and/or community service)records and reports.
• Counsel clients and patients, individually and in group sessions, to assist in overcoming dependencies (seeking new relationships), adjusting to life, and making changes.
• Collect information about clients through interviews, observations, and tests (and most importantly, speaking with and planning with the person).
• Act as the client’s advocate in order to coordinate required services or to resolve emergency problems in crisis situations. [often first line of emergency response]
• Develop and implement treatment (or "person-centered") plans based on clinical (and community) experience and knowledge.
• Collaborate with other staff members to perform clinical assessments (and health may be contracted for specific consultations) and develop treatment (service) plans.
• Evaluate client’s physical or mental condition (plan, not condition)based on review of client information. [Evaluate outcomes as planned with the client on a "quarterly basis".]

However, these position levels have undergone decades of academic field testing and recommendations with new competencies in development in 2011-2013 by the Centers for Medicaid and Medicare (at the categorical aide levels). New professionals were recommended with a community services coordinator (commonly known as "hands on" case management), together with services and personnel management, and community development and liaison roles for community participation.

School psychologist and inclusion educators

School psychologists' primary concern is with the academic, social, and emotional well-being of children within a scholastic environment. Unlike clinical psychologists, they receive much more training in education, child development and behavior, and the psychology of learning, often graduating with a post-master's educational specialist degree (EdS), EdD or Doctor of Philosophy (PhD) degree. Besides offering individual and group therapy with children and their families, school psychologists also evaluate school programs, provide cognitive assessment, help design prevention programs (e.g. reducing drops outs), and work with teachers and administrators to help maximize teaching efficacy, both in the classroom and systemically.

In today's world, the school psychologist remains the responsible party in "mental health" regarding children with emotional and behavioral needs, and have not always met these needs in the regular school environment. Inclusion (special)educators support participation in local school programs and after school programs, including new initiatives such as Achieve my Plan by the Research and Training Center on Family Support and Children's Mental Health at Portland State University. Referrals to residential schools and certification of the personnel involved in the residential schools and campuses have been a multi-decade concern with counties often involved in national efforts to better support these children and youth in local schools, families, homes and communities.

Psychiatric rehabilitation

Psychiatric rehabilitation, similar to cognitive rehabilitation, is a designated field in the rehabilitation often academically prepared in either Schools of Allied Health and Sciences (near the field of Physical Medicine and Rehabilitation) and as rehabilitation counseling in the School of Education. Both have been developed specifically as preparing community personnel (at the MA and PHD levels) and to aid in the transition to professionally competent and integrated community services. Psychiatric rehabilitation personnel have a community integration-related base, support a recovery and skills-based model of mental health, and may be involved with community programs based upon normalization and social role valorization throughout the US. Psychiatric rehabilitation personnel have been involved in upgrading the skills of staff in institutions in order to move clients into the community settings. Most common in international fields are community rehabilitation personnel which traditionally come from the rehabilitation counseling or community fields. In the new "rehabilitation centers" (new campus buildings), designed similar to hospital "rehab" (physical and occupational therapy, sports medicine), often no designated personnel in the fields of mental health (now "senior behavioral services" or "residential treatment units"). Psychiatric rehabilitation textbooks are currently on the market describing the community services their personnel were involved with in community development (commonly known as deinstitutionalization). 

Psychiatric rehabilitation professionals (and psychosocial services)are the mainstay of community programs in the US, and the national service providers association itself may certify mental health staff in these areas. Psychiatric interventions which vary from behavioral ones are described in a review on their use in "residential, vocational, social or educational role functioning" as a "preferred methods for helping individuals with serious psychiatric disabilities". Other competencies in education may involve working with families, user-directed planning methods and financing, housing and support, personal assistance services, transitional or supported employment, Americans with Disabilities Act (ADA), supported housing, integrated approaches (e.g., substance use, or intellectual disabilities), and psychosocial interventions, among others. In addition, rehabilitation counselors (PhD, MS) may also be educated "generically" (breadth and depth) or for all diagnostic groups, and can work in these fields; other personnel may have certifications in areas such as supported employment which has been verified for use in psychiatric, neurological, traumatic brain injury, and intellectual disabilities, among others.

Social worker

Social workers in the area of mental health may assess, treat, develop treatment plans, provide case management and/or rights advocacy to individuals with mental health problems. They can work independently or within clinics/service agencies, usually in collaboration with other health care professionals. 

In the US, they are often referred to as clinical social workers; each state specifies the responsibilities and limitations of this profession. State licensing boards and national certification boards require clinical social workers to have a master's or doctoral degree (MSW or DSW/PhD) from a university. The doctorate in social work requires submission of a major original contribution to the field in order to be awarded the degree. 

In the UK there is a now a standardized three-year undergraduate social work degree, or two-year postgraduate master's for those who already have an undergraduate social sciences degree or others and relevant work experience. These courses include mandatory supervised work experience in social work, which may include mental health services. Successful completion allows an individual to register and work as a qualified social worker. There are various additional optional courses for gaining qualifications specific to mental health, for example training in psychotherapy or, in England and Wales, for the role of Approved Mental Health Professional (two years' training for a legal role in the assessment and detention of eligible mentally disordered people under the Mental Health Act (1983) as amended in 2007).

Social workers in England and Wales are now able to become Approved Clinicians under the Mental Health Act 2007 following a period of further training (likely at postgraduate degree/diploma or doctoral level). Historically, this role was reserved for psychiatrist medical doctors, but has now extended to registered mental health professionals, such as social workers, psychologists and mental health nurses.

In general, it is the psycho-social model rather than, or in addition to, the dominant medical model, that is the underlying rationale for mental health social work. This may include a focus on social causation, labeling, critical theory and social constructiveness. Many argue social workers need to work with medical and health colleagues to provide an effective service but they also need to be at the forefront of processes that include and empower service users.

Social workers also prepare social work administration and may hold positions in human services systems as administration or Executives to Administration in the US. Social workers, similar to psychiatric rehabilitation, updates its professional education programs based upon current developments in the fields (e.g., support services)and serve a multicultural client base.

Educational Requirements for Social Workers

In the United States, the minimum requirement for social workers is generally a bachelor's degree in social work, though a bachelor's degree in a related field such as sociology or psychology may qualify an applicant for certain jobs. Higher-level jobs typically require a master's degree in social work. Master’s programs in social work usually last two years and consist of at least 900 hours of supervised instruction in the field. Regulatory boards generally require that degrees be obtained from programs that are accredited by the Council of Social Work Education (CSWE) or another nationally recognized accrediting agency for promotion and future collaboration.

Before social workers can practice, they are required to meet the licensing, certification, or registration requirements of the state. The requirements vary depending on the state but usually involve a minimum number of supervised hours in the field and passing of an exam. All states except California also require pre-licensure from the Association of Social Work Boards (ASWB).

The ASWB offers four categories of social work license. The lowest level is a Bachelors, for which a bachelor's degree in social work is required. The next level up is a Masters and a master's degree in social work is required. The Advanced Generalist category of social worker requires a master's degree in social work and two years of supervised post-degree experience. The highest ASWB category is a Clinical Social Worker which requires a master's degree in social work along with two years of post-master’s direct experience in social work.

Continuing Education Requirements for Social Workers

Most states require social workers to acquire a minimum number of continuing education credits per license, certification, or registration renewal period. The purpose of these requirements is to ensure that social workers stay up-to-date with information and practices in their professions. In most states, the renewal process occurs every two or three years. The number of continuing education credits that is required varies between states but is generally 20 to 45 hours during the two- or three-year period prior to renewal. 

Courses and programs that are approved as continuing education for social workers generally must be relevant to the profession and contribute to the advancement of professional competence. They often include continuing education courses, seminars, training programs, community service, research, publishing articles, or serving on a panel. Many states enforce that a minimum amount of the credits be on topics such as ethics, HIV/AIDs, or domestic violence.

Psychiatric and mental health nurse

Psychiatric Nurses or Mental Health Nurse Practitioners work with people with a large variety of mental health problems, often at the time of highest distress, and usually within hospital settings. These professionals work in primary care facilities, outpatient mental health clinics, as well as in hospitals and community health centers. MHNPs evaluate and provide care for patients who have anything from psychiatric disorders, medical mental conditions, to substance abuse problems. They are licensed to provide emergency psychiatric services, assess the psycho-social and physical state of their patients, create treatment plans, and continually manage their care. They may also serve as consultants or as educators for families and staff; however, the MHNP has a greater focus on psychiatric diagnosis (typically the province of the MD or PhD), including the differential diagnosis of medical disorders with psychiatric symptoms and on medication treatment for psychiatric disorders.

Educational requirements for psychiatric and mental health nurses

Psychiatric and mental health nurses receive specialist education to work in this area. In some countries it is required that a full course of general nurse training be completed prior to specializing as a psychiatric nurse. In other countries, such as the U.K., an individual completes a specific nurse training course that determines their area of work. As with other areas of nursing, it is becoming usual for psychiatric nurses to be educated to degree level and beyond. Psychiatric aides, now being trained by educational psychology in 2014, are part of the entry level workforce which is projected to be needed in communities in the US in the next decades.

In order to become a nurse practitioner in the U.S., at least six years of college education must be obtained. After earning the bachelor's degree (usually in nursing, although there are master's entry level nursing graduate programs intended for individuals with a bachelor's degree outside of nursing) the test for license as a registered nurse (the NCLEX-RN) must be passed. Next, the candidate must complete a state-approved master's degree advanced nursing education program which includes at least 600 clinical hours. Several schools are now also offering further education and awarding a DNP (Doctor of Nursing Practice). 

Individuals who choose a master's entry level pathway will spend an extra year at the start of the program taking classes necessary to pass the NCLEX-RN. Some schools will issue a BSN, others will issue a certificate. The student then continues with the normal MSN program.

Mental health care navigator

A mental health care navigator is an individual who assists patients and families to find appropriate mental health caregivers, facilities and services. Individuals who are care navigators are often also trained therapists and doctors. The need for mental health care navigators arises from the fragmentation of the mental health industry, which can often leave those in need with more questions than answers. Care navigators work closely with patients through discussion and collaboration to provide information on options and referrals to healthcare professionals, facilities, and organizations specializing in the patients’ needs. The difference between other mental health professionals and a care navigator is that a care navigator provides information and directs a patient to the best help rather than offering diagnosis, prescription of medications or treatment.

Many mental health organizations use “navigator” and “navigation” to describe the service of providing guidance through the health care industry. Care navigators are also sometimes referred to as “system navigators”. One type of care navigator is an "educational consultant."

Workforce Shortage

Behavioral health disorders are prevalent in the United States, but accessing treatment can be challenging. Nearly 1 in 5 adults experience a mental health condition for which approximately only 43% received treatment. When asked about access to mental health treatment, two-thirds of primary care physicians reported that they were unable to secure outpatient mental health treatment for their patients. This is due, in part, to the workforce shortage in behavioral health. In rural areas, 55% of US counties have no practicing psychiatrist, psychologist, or social worker. Overall, 77% of counties have a severe shortage of mental health workers and 96% of counties had some unmet need. Some of the reasons for the workforce shortage include high turnover rates, high levels of work-related stress, and inadequate compensation. Annual turnover rate is 33% for clinicians and 23% for clinical supervisors. This is compared to an annual PCP turnover rate of 7.1%. Compensation in behavioral health field is notably low. The average licensed clinical social worker, a position that requires a master's degree and 2000 hours of post graduate experience, earns $45,000/year on average. As a point of reference, the average physical therapist earns $75,000/year on average. Substance abuse counselor earnings are even lower, with an average salary of $34,000/year. Job stress is another factor that may lead to the high turnover rates and workforce shortage. It is estimated that 21-67% of mental health workers experience high levels of burnout including symptoms of emotional exhaustion, high levels of depersonalization and a reduced sense of personal accomplishment. Researchers have offered various recommendations to reduce the critical workforce gaps in behavioral health. Some of these recommendations include the following: expanding loan repayment programs to incentivize mental health providers to work in underserved (often rural) areas, integrating mental health into primary care, and increasing reimbursement to health care professionals.

Social workers also tend to experience competing work and family demands, which negatively affects their job well-being and subsequently their job satisfaction, resulting in high turnover in the profession.