Strontium

From Wikipedia, the free encyclopedia

Strontium,  ₃₈Sr

Strontium
Pronunciation	/ˈstrɒnʃiəm, -tiəm/ ​(STRON-shee-əm, -⁠tee-əm)
Appearance	silvery white metallic; with a pale yellow tint
Standard atomic weight Ar, std(Sr)	87.62(1)
Strontium in the periodic table
Hydrogen Helium Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson Ca ↑ Sr ↓ Ba rubidium ← strontium → yttrium
Atomic number (Z)	38
Group	group 2 (alkaline earth metals)
Period	period 5
Block	s-block
Element category	alkaline earth metal
Electron configuration	[Kr] 5s2
Electrons per shell	2, 8, 18, 8, 2
Physical properties
Phase at STP	solid
Melting point	1050 K ​(777 °C, ​1431 °F)
Boiling point	1650 K ​(1377 °C, ​2511 °F)
Density (near r.t.)	2.64 g/cm3
when liquid (at m.p.)	2.375 g/cm3
Heat of fusion	7.43 kJ/mol
Heat of vaporization	141 kJ/mol
Molar heat capacity	26.4 J/(mol·K)
Vapor pressure P (Pa) 1 10 100 1 k 10 k 100 k at T (K) 796 882 990 1139 1345 1646
Atomic properties
Oxidation states	+1, +2 (a strongly basic oxide)
Electronegativity	Pauling scale: 0.95
Ionization energies	1st: 549.5 kJ/mol 2nd: 1064.2 kJ/mol 3rd: 4138 kJ/mol
Atomic radius	empirical: 215 pm
Covalent radius	195±10 pm
Van der Waals radius	249 pm
Spectral lines of strontium
Other properties
Natural occurrence	primordial
Crystal structure	​face-centered cubic (fcc)
Thermal expansion	22.5 µm/(m·K) (at 25 °C)
Thermal conductivity	35.4 W/(m·K)
Electrical resistivity	132 nΩ·m (at 20 °C)
Magnetic ordering	paramagnetic
Magnetic susceptibility	−92.0·10−6 cm3/mol (298 K)
Young's modulus	15.7 GPa
Shear modulus	6.03 GPa
Poisson ratio	0.28
Mohs hardness	1.5
CAS Number	7440-24-6
History
Naming	after the mineral strontianite, itself named after Strontian, Scotland
Discovery	William Cruickshank (1787)
First isolation	Humphry Davy (1808)
Main isotopes of strontium
Iso­tope Abun­dance Half-life (t1/2) Decay mode Pro­duct 82Sr syn 25.36 d ε 82Rb 83Sr syn 1.35 d ε 83Rb β+ 83Rb γ – 84Sr 0.56% stable 85Sr syn 64.84 d ε 85Rb γ – 86Sr 9.86% stable 87Sr 7.00% stable 88Sr 82.58% stable 89Sr syn 50.52 d ε 89Rb β− 89Y 90Sr trace 28.90 y β− 90Y

Strontium is the chemical element with symbol Sr and atomic number 38. An alkaline earth metal, strontium is a soft silver-white yellowish metallic element that is highly chemically reactive. The metal forms a dark oxide layer when it is exposed to air. Strontium has physical and chemical properties similar to those of its two vertical neighbors in the periodic table, calcium and barium. It occurs naturally mainly in the minerals celestine and strontianite, and is mostly mined from these. While natural strontium is stable, the synthetic ⁹⁰Sr isotope is radioactive and is one of the most dangerous components of nuclear fallout, as strontium is absorbed by the body in a similar manner to calcium. Natural stable strontium, on the other hand, is not hazardous to health.

Both strontium and strontianite are named after Strontian, a village in Scotland near which the mineral was discovered in 1790 by Adair Crawford and William Cruickshank; it was identified as a new element the next year from its crimson-red flame test color. Strontium was first isolated as a metal in 1808 by Humphry Davy using the then-newly discovered process of electrolysis. During the 19th century, strontium was mostly used in the production of sugar from sugar beet. At the peak of production of television cathode ray tubes, as much as 75 percent of strontium consumption in the United States was used for the faceplate glass. With the replacement of cathode ray tubes with other display methods, consumption of strontium has dramatically declined.

Characteristics

Oxidized dendritic strontium

 

Strontium is a divalent silvery metal with a pale yellow tint whose properties are mostly intermediate between and similar to those of its group neighbors calcium and barium. It is softer than calcium and harder than barium. Its melting (777 °C) and boiling (1655 °C) points are lower than those of calcium (842 °C and 1757 °C respectively); barium continues this downward trend in the melting point (727 °C), but not in the boiling point (2170 °C). The density of strontium (2.64 g/cm³) is similarly intermediate between those of calcium (1.54 g/cm³) and barium (3.594 g/cm³). Three allotropes of metallic strontium exist, with transition points at 235 and 540 °C.

The standard electrode potential for the Sr²⁺/Sr couple is −2.89 V, approximately midway between those of the Ca²⁺/Ca (−2.84 V) and Ba²⁺/Ba (−2.92 V) couples, and close to those of the neighboring alkali metals.^[10] Strontium is intermediate between calcium and barium in its reactivity toward water, with which it reacts on contact to produce strontium hydroxide and hydrogen gas. Strontium metal burns in air to produce both strontium oxide and strontium nitride, but since it does not react with nitrogen below 380 °C, at room temperature, it forms only the oxide spontaneously. Besides the simple oxide SrO, the peroxide SrO₂ can be made by direct oxidation of strontium metal under a high pressure of oxygen, and there is some evidence for a yellow superoxide Sr(O₂)₂. Strontium hydroxide, Sr(OH)₂, is a strong base, though it is not as strong as the hydroxides of barium or the alkali metals. All four dihalides of strontium are known.

Due to the large size of the heavy s-block elements, including strontium, a vast range of coordination numbers is known, from 2, 3, or 4 all the way to 22 or 24 in SrCd₁₁ and SrZn₁₃. The Sr²⁺ ion is quite large, so that high coordination numbers are the rule. The large size of strontium and barium plays a significant part in stabilising strontium complexes with polydentate macrocyclic ligands such as crown ethers: for example, while 18-crown-6 forms relatively weak complexes with calcium and the alkali metals, its strontium and barium complexes are much stronger.

Organostrontium compounds contain one or more strontium–carbon bonds. They have been reported as intermediates in Barbier-type reactions. Although strontium is in the same group as magnesium, and organomagnesium compounds are very commonly used throughout chemistry, organostrontium compounds are not similarly widespread because they are more difficult to make and more reactive. Organostrontium compounds tend to be more similar to organoeuropium or organosamarium compounds due to the similar ionic radii of these elements (Sr²⁺ 118 pm; Eu²⁺ 117 pm; Sm²⁺ 122 pm). Most of these compounds can only be prepared at low temperatures; bulky ligands tend to favor stability. For example, strontium dicyclopentadienyl, Sr(C₅H₅)₂, must be made by directly reacting strontium metal with mercurocene or cyclopentadiene itself; replacing the C₅H₅ ligand with the bulkier C₅(CH₃)₅ ligand on the other hand increases the compound's solubility, volatility, and kinetic stability.

Because of its extreme reactivity with oxygen and water, strontium occurs naturally only in compounds with other elements, such as in the minerals strontianite and celestine. It is kept under a liquid hydrocarbon such as mineral oil or kerosene to prevent oxidation; freshly exposed strontium metal rapidly turns a yellowish color with the formation of the oxide. Finely powdered strontium metal is pyrophoric, meaning that it will ignite spontaneously in air at room temperature. Volatile strontium salts impart a bright red color to flames, and these salts are used in pyrotechnics and in the production of flares. Like calcium and barium, as well as the alkali metals and the divalent lanthanides europium and ytterbium, strontium metal dissolves directly in liquid ammonia to give a dark blue solution.

Isotopes

Natural strontium is a mixture of four stable isotopes: ⁸⁴Sr, ⁸⁶Sr, ⁸⁷Sr, and ⁸⁸Sr. Their abundance increases with increasing mass number and the heaviest, ⁸⁸Sr, makes up about 82.6% of all natural strontium, though the abundance varies due to the production of radiogenic ⁸⁷Sr as the daughter of long-lived beta-decaying ⁸⁷Rb. Of the unstable isotopes, the primary decay mode of the isotopes lighter than ⁸⁵Sr is electron capture or positron emission to isotopes of rubidium, and that of the isotopes heavier than ⁸⁸Sr is electron emission to isotopes of yttrium. Of special note are ⁸⁹Sr and ⁹⁰Sr. The former has a half-life of 50.6 days and is used to treat bone cancer due to strontium's chemical similarity and hence ability to replace calcium. While ⁹⁰Sr (half-life 28.90 years) has been used similarly, it is also an isotope of concern in fallout from nuclear weapons and nuclear accidents due to its production as a fission product. Its presence in bones can cause bone cancer, cancer of nearby tissues, and leukemia. The 1986 Chernobyl nuclear accident contaminated about 30,000 km² with greater than 10 kBq/m² with ⁹⁰Sr, which accounts for 5% of the core inventory of ⁹⁰Sr.

History

Flame test for strontium

 

Strontium is named after the Scottish village of Strontian (Gaelic Sròn an t-Sìthein), where it was discovered in the ores of the lead mines. Thomas Charles Hope originally named the element strontianite, but the name was soon after shortened to strontium.

In 1790, Adair Crawford, a physician engaged in the preparation of barium, and his colleague William Cruickshank, recognised that the Strontian ores exhibited properties that differed from those in other "heavy spars" sources. This allowed Adair to conclude on page 355 "... it is probable indeed, that the scotch mineral is a new species of earth which has not hitherto been sufficiently examined." The physician and mineral collector Friedrich Gabriel Sulzer analysed together with Johann Friedrich Blumenbach the mineral from Strontian and named it strontianite. He also came to the conclusion that it was distinct from the witherite and contained a new earth (neue Grunderde). In 1793 Thomas Charles Hope, a professor of chemistry at the University of Glasgow proposed the name strontites. He confirmed the earlier work of Crawford and recounted: "... Considering it a peculiar earth I thought it necessary to give it an name. I have called it Strontites, from the place it was found; a mode of derivation in my opinion, fully as proper as any quality it may possess, which is the present fashion." The element was eventually isolated by Sir Humphry Davy in 1808 by the electrolysis of a mixture containing strontium chloride and mercuric oxide, and announced by him in a lecture to the Royal Society on 30 June 1808. In keeping with the naming of the other alkaline earths, he changed the name to strontium.

The first large-scale application of strontium was in the production of sugar from sugar beet. Although a crystallisation process using strontium hydroxide was patented by Augustin-Pierre Dubrunfaut in 1849 the large scale introduction came with the improvement of the process in the early 1870s. The German sugar industry used the process well into the 20th century. Before World War I the beet sugar industry used 100,000 to 150,000 tons of strontium hydroxide for this process per year. The strontium hydroxide was recycled in the process, but the demand to substitute losses during production was high enough to create a significant demand initiating mining of strontianite in the Münsterland. The mining of strontianite in Germany ended when mining of the celestine deposits in Gloucestershire started. These mines supplied most of the world strontium supply from 1884 to 1941. Although the celestine deposits in the Granada basin were known for some time the large scale mining did not start before the 1950s.

During atmospheric nuclear weapons testing, it was observed that strontium-90 is one of the nuclear fission products with a relative high yield. The similarity to calcium and the chance that the strontium-90 might become enriched in bones made research on the metabolism of strontium an important topic.

Occurrence

The mineral celestine (SrSO₄)

Strontium commonly occurs in nature, being the 15th most abundant element on Earth (its heavier congener barium being the 14th), estimated to average approximately 360 parts per million in the Earth's crust and is found chiefly as the sulfate mineral celestine (SrSO₄) and the carbonate strontianite (SrCO₃). Of the two, celestine occurs much more frequently in deposits of sufficient size for mining. Because strontium is used most often in the carbonate form, strontianite would be the more useful of the two common minerals, but few deposits have been discovered that are suitable for development.

In groundwater strontium behaves chemically much like calcium. At intermediate to acidic pH Sr²⁺ is the dominant strontium species. In the presence of calcium ions, strontium commonly forms coprecipitates with calcium minerals such as calcite and anhydrite at an increased pH. At intermediate to acidic pH, dissolved strontium is bound to soil particles by cation exchange.

The mean strontium content of ocean water is 8 mg/l. At a concentration between 82 and 90 µmol/l of strontium, the concentration is considerably lower than the calcium concentration, which is normally between 9.6 and 11.6 mmol/l. It is nevertheless much higher than that of barium, 13 μg/l.

Production

Strontium producers in 2014

 

The three major producers of strontium as celestine as of 2015 are China (150,000 t), Spain (90,000 t), and Mexico (70,000 t); Argentina (10,000 t) and Morocco (2,500 t) are smaller producers. Although strontium deposits occur widely in the United States, they have not been mined since 1959.

A large proportion of mined celestine (SrSO₄) is converted to the carbonate by two processes. Either the celestine is directly leached with sodium carbonate solution or the celestine is roasted with coal to form the sulfide. The second stage produces a dark-coloured material containing mostly strontium sulfide. This so-called "black ash" is dissolved in water and filtered. Strontium carbonate is precipitated from the strontium sulfide solution by introduction of carbon dioxide. The sulfate is reduced to the sulfide by the carbothermic reduction:

SrSO₄ + 2 C → SrS + 2 CO₂

About 300,000 tons are processed in this way annually.

The metal is produced commercially by reducing strontium oxide with aluminium. The strontium is distilled from the mixture. Strontium metal can also be prepared on a small scale by electrolysis of a solution of strontium chloride in molten potassium chloride:

Sr²⁺ + 2
e⁻ → Sr

2 Cl⁻ → Cl₂ + 2
e⁻

Applications

CRT computer monitor front panel made from strontium and barium oxide-containing glass. This application used to consume most of the world's production of strontium.

 

Consuming 75% of production, the primary use for strontium is in glass for colour television cathode ray tubes, where it prevents X-ray emission. This application for strontium is declining because CRTs are being replaced by other display methods. This decline has a significant influence on the mining and refining of strontium. All parts of the CRT must absorb X-rays. In the neck and the funnel of the tube, lead glass is used for this purpose, but this type of glass shows a browning effect due to the interaction of the X-rays with the glass. Therefore, the front panel is made from a different glass mixture with strontium and barium to absorb the X-rays. The average values for the glass mixture determined for a recycling study in 2005 is 8.5% strontium oxide and 10% barium oxide.

Because strontium is so similar to calcium, it is incorporated in the bone. All four stable isotopes are incorporated, in roughly the same proportions they are found in nature. However, the actual distribution of the isotopes tends to vary greatly from one geographical location to another. Thus, analyzing the bone of an individual can help determine the region it came from. This approach helps to identify the ancient migration patterns and the origin of commingled human remains in battlefield burial sites.

⁸⁷Sr/⁸⁶Sr ratios are commonly used to determine the likely provenance areas of sediment in natural systems, especially in marine and fluvial environments. Dasch (1969) showed that surface sediments of Atlantic displayed ⁸⁷Sr/⁸⁶Sr ratios that could be regarded as bulk averages of the ⁸⁷Sr/⁸⁶Sr ratios of geological terranes from adjacent landmasses. A good example of a fluvial-marine system to which Sr isotope provenance studies have been successfully employed is the River Nile-Mediterranean system. Due to the differing ages of the rocks that constitute the majority of the Blue and White Nile, catchment areas of the changing provenance of sediment reaching the River Nile delta and East Mediterranean Sea can be discerned through strontium isotopic studies. Such changes are climatically controlled in the Late Quaternary.

More recently, ⁸⁷Sr/⁸⁶Sr ratios have also been used to determine the source of ancient archaeological materials such as timbers and corn in Chaco Canyon, New Mexico. ⁸⁷Sr/⁸⁶Sr ratios in teeth may also be used to track animal migrations.

Strontium aluminate is frequently used in glow in the dark toys, as it is chemically and biologically inert.

Strontium salts are added to fireworks in order to create red colors

 

Strontium carbonate and other strontium salts are added to fireworks to give a deep red colour. This same effect identifies strontium cations in the flame test. Fireworks consumes about 5% of the world's production. Strontium carbonate is used in the manufacturing of hard ferrite magnets.

Strontium chloride is sometimes used in toothpastes for sensitive teeth. One popular brand includes 10% total strontium chloride hexahydrate by weight. Small amounts are used in the refining of zinc to remove small amounts of lead impurities. The metal itself has a limited use as a getter, to remove unwanted gases in vacuums by reacting with them, although barium may also be used for this purpose.

The ultra-narrow optical transition between the [Kr]5s₂ ¹S₀ electronic ground state and the metastable [Kr]5s5p ³P₀ excited state of ⁸⁷Sr is one of the leading candidates for the future re-definition of the second in terms of an optical transition as opposed to the current definition derived from a microwave transition between different hyperfine ground states of ¹³³Cs. Current optical atomic clocks operating on this transition already surpass the precision and accuracy of the current definition of the second.

Radioactive strontium

⁸⁹Sr is the active ingredient in Metastron, a radiopharmaceutical used for bone pain secondary to metastatic bone cancer. The strontium is processed like calcium by the body, preferentially incorporating it into bone at sites of increased osteogenesis. This localization focuses the radiation exposure on the cancerous lesion.

RTGs from Soviet era lighthouses

 

⁹⁰Sr has been used as a power source for radioisotope thermoelectric generators (RTGs). ⁹⁰Sr produces approximately 0.93 watts of heat per gram (it is lower for the form of ⁹⁰Sr used in RTGs, which is strontium fluoride). However, ⁹⁰Sr has one third the lifetime and a lower density than ²³⁸Pu, another RTG fuel. The main advantage of ⁹⁰Sr is that it is cheaper than ²³⁸Pu and is found in nuclear waste. The Soviet Union deployed nearly 1000 of these RTGs on its northern coast as a power source for lighthouses and meteorology stations.

Biological role

Strontium

Hazards
GHS pictograms
GHS signal word	Danger
GHS hazard statements	H261, H315
GHS precautionary statements	P223, P231+232, P370+378, P422
NFPA 704	0 2 2 W

Acantharea, a relatively large group of marine radiolarian protozoa, produce intricate mineral skeletons composed of strontium sulfate. In biological systems, calcium is substituted in a small extent by strontium. In the human body, most of the absorbed strontium is deposited in the bones. The ratio of strontium to calcium in human bones is between 1:1000 and 1:2000, roughly in the same range as in the blood serum.

Effect on the human body

The human body absorbs strontium as if it were its lighter congener calcium. Because the elements are chemically very similar, stable strontium isotopes do not pose a significant health threat. The average human has an intake of about two milligrams of strontium a day. In adults, strontium consumed tends to attach only to the surface of bones, but in children, strontium can replace calcium in the mineral of the growing bones and thus lead to bone growth problems.

The biological half-life of strontium in humans has variously been reported as from 14 to 600 days, 1000 days, 18 years, 30 years and, at an upper limit, 49 years. The wide-ranging published biological half-life figures are explained by strontium's complex metabolism within the body. However, by averaging all excretion paths, the overall biological half-life is estimated to be about 18 years. The elimination rate of strontium is strongly affected by age and sex, due to differences in bone metabolism.

The drug strontium ranelate aids bone growth, increases bone density, and lessens the incidence of vertebral, peripheral, and hip fractures. However, strontium ranelate also increases the risk of venous thromboembolism, pulmonary embolism, and serious cardiovascular disorders, including myocardial infarction. Its use is therefore now restricted. Its beneficial effects are also questionable, since the increased bone density is partially caused by the increased density of strontium over the calcium which it replaces. Strontium also bioaccumulates in the body. Despite restrictions on strontium ranelate, strontium is still contained in some supplements. There is not much scientific evidence on risks of strontium chloride when taken by mouth. Those with a personal or family history of blood clotting disorders are advised to avoid strontium.

Strontium has been shown to inhibit sensory irritation when applied topically to the skin. Topically applied, strontium has been shown to accelerate the recovery rate of the epidermal permeability barrier (skin barrier).

Federation of American Scientists

From Wikipedia, the free encyclopedia

Federation of American Scientists
Headquarters	Washington, D.C.
Leaders
• President	Ali Nouri
Establishment
• Founded	6 January 1946
Website fas.org

The Federation of American Scientists (FAS) is a 501(c)(3) organization with the stated intent of using science and scientific analysis to attempt to make the world more secure. FAS was founded in 1945 by scientists who worked on the Manhattan Project to develop the first atomic bombs. The Federation of American Scientists also aims to reduce the amount of nuclear weapons that are in use, and prevent nuclear and radiological terrorism. They hope to present high standards for nuclear energy’s safety and security, illuminate government secrecy practices, as well as track and eliminate the global illicit trade of conventional, nuclear, biological and chemical weapons. With 100 sponsors, the Federation of American Scientists claims that it promotes a safer and more secure world by developing and advancing solutions to important science and technology security policy problems by educating the public and policy makers, and promoting transparency through research and analysis to maximize impact on policy. FAS projects are organized in three main programs: nuclear security, government secrecy, and biosecurity. FAS played a role in the control of atomic energy and weapons, as well as better international monitoring of atomic activities.

History

FAS logo

 

FAS was founded as the Federation of Atomic Scientists on November 30, 1945, by a group of scientists and engineers within the Associations of Manhattan Project Scientists, Oak Ridge Scientists, and Los Alamos Scientists. Its early mission was to support the McMahon Act of 1946, educate the public, press, politicians, and policy-makers, and promote international transparency and nuclear disarmament. The group was frustrated with the control of the nation's nuclear arsenal and advocated for public control of the nuclear arsenal. A group of the early members of the Federation of American Scientists went to Washington D.C. and set up there sending letters to representatives in the House of Representatives and in the Senate to request support for their original goal to not support the May-Johnson Bill. The group of scientists were opposed to the fact that, under the proposed May-Johnson Bill, the United States military would have the majority of control over the development and control of atomic weapons. Working with congressmen, they worked to create the bill that brought forth the Atomic Energy Commission (AEC). The Atomic Energy Commission oversaw the research into atomic energy and atomic weapons. On January 6, 1946, FAS changed its name to the Federation of American Scientists, but its purpose remained the same—to agitate for the international control of atomic energy and its devotion to peaceful uses, public promotion of science and the freedom and integrity of scientists and scientific research. For this purpose, permanent headquarters were set up in Washington, D.C., and contacts were established with the several branches of government, the United Nations, professional and private organizations, and influential persons. The explosion of postwar political activism demonstrated by the group became known as the "scientists' movement" with the basis of being unhappy with the United States' monopoly on nuclear weapons. During this movement, the idea was also established that no defense against an atomic bomb was feasible in the near future. Using these two ideas, the FAS proposed the United States and other technologically advanced nations had to work in unison to create a solution that would not end in complete destruction.

In 1946, the FAS worked with the Ad Council to broadcast a list of facts regarding the state of the United Nations atomic energy negotiations as well as the American proposal for atomic development. In a rare example of an effort to simply give listeners facts with little to no political or personal bias, the scientists at FAS were able to broadcast this information to the public in hopes of informing the public to be "armed with the facts -- instead of swayed by emotions or prejudices." Throughout the course of trying to give the public information, the FAS attempted to coordinate with PR agencies to better connect with the audience. Most of these plans fell through as the agencies typically did not see eye-to-eye with members of the FAS. Scientists realized the importance of getting their point across, but conveying that to someone who had little to no background knowledge on the subject of atomic energy proved to be a challenge, a challenge that would stick with the FAS for many years. Many scientists from more localized organizations had comments like "We have failed. The people have not understood us or our foreign policy would have changed."

By 1948, the Federation had grown to twenty local associations, with 2,500 members, and had been instrumental in the passage of the McMahon Act and the National Science Foundation, and had influenced the American position in the United Nations with regard to international control of atomic energy and disarmament.

In addition to influencing government policy, it undertook a program of public education on the nature and control of atomic energy through lectures, films, exhibits, and the distribution of literature, coordinating its own activities with that of member organizations through the issue of memorandum, policy statements, information sheets, and newsletters. 

Nearly ninety percent of Manhattan Project personnel were in approval of the FAS. With few comparing the group to a "scientists' lobby." 

Mission

The mission of FAS is to promote a safer and more secure world by developing and advancing solutions to important science and technology security policy problems by educating the public and policy makers, and promoting transparency through research and analysis to maximize impact on policy. This mission was established early on and was deemed necessary for the federation, as decisions made by the United States during the conception of the FAS were critical in terms of shaping international relations. The FAS wanted the public to become more critical and aware of the government, in order to monitor the decisions that were made to ensure that they matched what the public actually wanted. The FAS would act to inform the public about how destructive the improper use of atomic energy could be and emphasize the need to enforce international control of atomic weapons and energy.

Membership

In 1969 the FAS had a rough annual budget of $7,000 and relied on mostly volunteer staff. In 1970 Jeremy J. Stone was selected as president of the organization and was the only staff member for the next 5 years. Due to Stone being the president and only member of the organization he influenced the future and direction of the organization heavily. With an increased budget in the 1990s FAS was able to employ a staff of about a dozen people and expand membership of the organization.

In the mid 1980’s the FAS began relying more heavily on journalist, professional staff and analyst rather than famous scientists as it did previously in its history. This showed the organization’s shift towards public information and transparency in the government and away from secrecy in covert projects and finances. In 2000 Henry Kelly became the new president and further perused the goals of the program of bolstering science in policy and focusing on using that science to further benefit the public.

In a 2002 survey conducted within the FAS found that nearly thirty percent of members were physicists. While the next largest fields represented were medicine, biology, engineering, and chemistry. With the latter four fields making up another sixty one percent of the total member population. Members also received complementary copies of "Secrecy News," an electronic newsletter regarding government secrecy and intelligence.

Finances

In the 2004 fiscal year, the FAS ran on a $3 million budget. Over sixty percent of the budget came from private contributions while another third came from government grants. With membership dues alone, the federation achieved a profit of $125,000. The Federation of American Scientists receive many grants for the work that they do. They have received grants from the Ploughshares Fund and from the New Land Foundation for continuing their work to keep the public informed of the state of nuclear weapons across the world. In addition the Federation of American Scientists receives grants from the Carnegie Corporation of New York for their work on the Nuclear Information Project.

Funding from the MacArthur Foundation

Federation of American Scientists was awarded $10,586,000 between 1984 and 2017, including 25 grants in International Peace & Security, MacArthur Award for Creative & Effective Institutions, and Nuclear Challenges. In 2004 the Federation of American Scientists received their largest grant from the MacArthur Foundation of $2,400,000 in support of everything that they do.

The Chronological List of the Grants that the Federation of American Scientists has received from the MacArthur Foundation (As of April 16, 2019) is as follows: 

2018 - The Federation of American Scientists received a grant for $210,000 through the International Peace and Security program. The project title was, "For modifying liability structures and market incentives to give insurance and financial institutions leverage tools to enhance nuclear security." Through this project, the (FAS) will convene a small task force of experts from legal, nuclear, and financial domains to generate and review options for improving nuclear-security-related incentives that apply to insurance companies, banks, and corporations. The task force will seek areas where the law is unsettled or inadequately focused on security risks, and will identify and promote practical steps to address these gaps. This grant is still in use until June 2019. 

2017 - The Federation of American Scientists received two grants, one for $1,870,000 and a second grant for $50,000 to continue their efforts to promote stability in the world. The MacArthur Foundation found that their work with Nuclear Arms and the Nuclear Information Project (see below), and their effort to help with the disposal of nuclear material after using it for nuclear energy was helping the stability and safety of the world.

2015 - The Federation of American Scientists received two grants, one for $684,000 and a second grant for $200,000. The MacArthur foundation awarded them these grants because of the Federation of American Scientist's work in regards to Naval use of nuclear energy, specifically in the nuclear reactors found on aircraft carriers and submarines. In addition to the naval nuclear energy, the MacArthur foundation awarded the second grant of $200,000 so that the Federation of American Scientists could independently verify information about the Iran Nuclear Deal.

2014 - The Federation of American Scientists received a $140,000 grant.

2013 - The Federation of American Scientists received a $145,000 grant for their work on the naval propulsion reactors that work with uranium.

2012 - The Federation of American Scientists received a grant for $50,000 through the International Peace and Security program. This grant was to help assist in strategic planning. It lasted for 12 months. 

2009 - Received a grant for $25,000.

2009- The Federation of American Scientists received a grant for $250,000 through the International Peace and Security program. This grant was in use for 33 months and was used to assist in finding new approaches to nuclear transparency.

2008 - Received a grant for $300,000 to make information about nuclear weapons available to the public.

2007 - The Federation of American Scientists received a grant for $612,318 through the International Peace and Security program. This grant was in use for 48 months, or four years, and was a final grant used toward a project to strengthen the link between the biological research and security policy communities.

2006 - Received a grant for $590,000.

2006 - The Federation of American Scientists received a grant for $500,000 through the International Peace and Security program. This grant was in use for 24 months, and was used toward a project to strengthen the link between the biological research and security policy communities.

2004 - Received a grant for $2,500,000.

Nuclear Security Program

Continuing the FAS tradition of international control of atomic energy and devotion to its peaceful uses, the Nuclear Security Program pursues projects that create a more secure world. The Nuclear Security Program (NSP) includes program work that focuses on reducing the risks of further nuclear proliferation and nuclear terrorism. 

The NSP has key areas of research in order to promote nuclear security around the world. The program focuses on:

• Signatures of nuclear materials and processes 
• Prevention, detection, interdiction, and response for illicit nuclear/radioactive threats
• Applications of nuclear probes for detection of security-relevant materials
• Application of nuclear security in real-world settings
• Policy, law, and diplomacy relating to global nuclear security.

Nuclear Information Project

The Nuclear Information Project provides the general public and policy-makers with information and analysis on the status, number, and operation of nuclear weapons, the policies that guide their potential use and nuclear arms control. The project reports on developments in the nuclear fuel cycle that are relevant to nuclear weapons proliferation. The project puts technical information into a nonproliferation context and looks at case studies by conducting independent calculations and analyses. In addition to covering information over the quantities of nuclear arms in the world, they make it user friendly for those who are not nuclear physicists. In the nuclear fuel part of the report, the Federation of American Scientists covers the state of nuclear fuel and the Global Nuclear Energy Partnership (GNEP). The whole goal of the Nuclear Information Project is to keep the public the most educated on nuclear weapons so that they can make the most educated decisions when it comes to policy making in regards to nuclear energy or nuclear weapons.

The Nuclear Information Project is run by Hans M. Kristensen.

Government Secrecy

The Government Secrecy Project works to promote public access to government information and to illuminate the apparatus of government secrecy, including national security classification and declassification policies. The project also publishes previously undisclosed or hard-to-find government documents of public policy interest, as well as resources on intelligence policy.

The project publication is Secrecy News, which reports on new developments in government secrecy and provides public access to documentary resources on secrecy, intelligence, and national security policy.

The Government Secrecy Project is directed by Steven Aftergood, who is also editor and author of Secrecy News.

Legacy programs and projects

Arms Sales Monitoring Project

The Arms Sales Monitoring Project (ASMP) worked to increase transparency, accountability and restraint in the legal arms trade; eradicate the illicit arms trade; and served as a repository of data on U.S. arms transfers and arms export controls. Project work focused on the arms trade, U.S. arms export policies, and the illicit trade in small arms and light weapons through the publication of reports and articles, media outreach, and public speaking.

The Advisory Board for the Arms Sales Monitoring Project included Ambassador Jayantha Dhanapala, Dr. Bruce Hoffman, and Dr. Moisés Naím. 

The project was sponsored by: CarEth Foundation, Compton Foundation, Inc., Greenville Foundation, John D. and Catherine T. MacArthur Foundation, Stewart R. Mott Charitable Trust,  Ploughshares Fund, Samuel Rubin Foundation, Spanel Foundation, Inc., and Winston Foundation for World Peace.

The Arms Sales Monitoring Project was discontinued in 2014.

Biosecurity Program

The Biosecurity Program concentrates on researching and advocating policies that balance science and security without compromising national security or scientific progress. This includes preventing the misuse of research and promoting the public understanding of the real threats from biological and chemical weapons. The Federation of American Scientists also concentrates on researching and keeping the public informed on genetic engineering and genetic modification as a subset of their biosecurity program. One of their major concerns is resistance that species can develop to certain modifications from genetic resistance or from the use of antibiotics.

The biosecurity program is specifically designed to prevent the use of biological agents and pathogens. Because there have only been few instances in which individuals have attempted to misuse life sciences, the effectiveness of biosecurity programs is currently difficult to detect. Improving biosecurity programs in the future will rely heavily on using metrics to determine outcomes (the impact of what was done). Goals of the programs are quantitative in nature, including an increase in agents secured as well as scientists engaged.

The big concerns with biosecurity are accidental biological threats, intentional malicious biological threats, and natural biological threat occurrences. Because of these threats the Virtual Biosecurity Center (VBC) was set up. 

The Virtual Biosecurity Center (VBC) was founded in 2011 and is spearheaded by the Federation of American Scientists. The VBC is committed to counteracting threats posed by the development of biological weapons as well as ensuring individuals use science and technology responsibly. The Virtual Biosecurity Center provides the public with a resource to find the latest updates on biosecurity policy, bioterrorism information, and biodefense research.

The Virtual Biosecurity Center provides and promotes biosecurity information, education, best practices and collaboration. Additionally, VBC offers significant news and events regarding biosecurity, a regularly updated education center and library, a global forum on Bio risks, an online informative policy tool, empowering partnerships among other professional biosecurity communities around the world, scheduled global conferences to raise awareness and develop plans for current and future biosecurity issues, as well as partnerships to tighten the gap between the scientific, public health, intelligence and law enforcement communities.

In addition to the Virtual Biosecurity Center, the Federation of American Scientists has a public resource available known as the Biosecurity and Biodefence Resource. The purpose of the Biosecurity and Biodefence Resource is to keep the public informed on information about biological policy of governments and research institutes across the world.

Military Analysis Network

The Military Analysis Network offered information on U.S. and Foreign Weapon Systems, Munitions, and Weapons in Space. The Network provided resources and databases in several categories including:

• A guide to United States Munitions and Weapons Systems
• Rest of World Military Equipment by Country Index
• United States Military Logistics Index
• Selected Country Military Summaries Index
• Report on Weapons in Space

This is a legacy project and information is no longer updated by FAS staff.

Learning Technologies Program

The Learning Technologies Program (LTP) focused on ways to use innovative technologies to improve how people teach and learn. The LTP created prototype games and learning tools and assembled collaborative projects consisting of NGOs, design professionals, and community leaders to undertake innovative education initiatives at both the national and local level. 

The Project worked to help create learning tools to bring about major gains in learning and training. The major project of the Program is Immune Attack, a fully 3-D game in which high school students discover the inner workings of the body's circulatory and immune systems, as they pilot a tiny drone through the bloodstream to fight microscopic invaders.

Immune Attack was jointly developed by the Federation of American Scientists, the University of Southern California, Brown University, and Escape Hatch Entertainment. Immune Attack is a supplemental teaching tool, designed to be used in addition to middle school and high school biology textbooks. It introduces molecular biology and cellular biology in detail that is usually reserved for college students. However, it uses the familiar and motivational video game format to introduce the strange and new world of cells and molecules.

The Learning Technologies Program was discontinued in 2013.

Earth Systems Program

The Earth Systems Program (ESP) examined the increased stresses on the environment, including issues relating to energy, food, agriculture, water, and other natural resources, and to analyze how they interact with respect to international security. ESP was created out of the idea that technology should allow people worldwide to improve their living standards and amenities through secure and environmentally friendly ways. The program worked improve dialogue and trust between environmental scientists, policy makers, and the public, as well as to develop science partnerships to solve critical environment and energy problems.

The Earth Systems Program achieves its goals under one specific mission statement:

Over the next century the earth’s resilience and adaptive capabilities will be stressed by the demands of global climate change, environmental degradation, a population of over six billion people, and the accompanying increased resource and energy demand. These stresses will place an additional burden upon the earth’s natural systems and the processes and resources that drive these systems. Future system scarcities and imbalances represent a security concern with the potential to destabilize and weaken existing political, social, and economic structures. And as these natural systems are inherently highly interdependent, it is necessary for them to be analyzed and considered systemically.

To meet their goals, ESP puts a focus on these specific plan areas:

• Transparency
• Technology
• Inquiry
• Policy
• Partnership

Building Technologies Project

The FAS Building Technologies Project was initiated in 2001 to focus the efforts of scientists and engineers who specialize in building materials on a range of issues such as structural engineering, indoor air quality, energy efficiency, and architectural design to create homes that are safe, affordable, and attractive to builders and owners in the United States and abroad. 

The Building Technologies Program worked to advance innovation in building design and construction that can improve quality, affordability, energy efficiency and hazard protection while lowering construction and operating costs. Technical advances, including new composite materials and prefabricated components, help to meet these goals in ways that are beneficial for builders and owners. The Building Technologies Project combined the talents of renowned architects and engineers along with the nation’s leading energy experts to embark upon housing issues in the United States and abroad.

Program areas included:

• Manufactured housing
• Relief housing
• Advanced technologies
• Learning technologies and training
• Policy issues

The Building Technologies Project was discontinued in 2012.

Publications

Some of the recent article and report publications are as follows:

• September 15, 2017, "Nuclear Monitoring and Verification in the Digital Age: Seven Recommendations for Improving the Process"
• August 23, 2017, "The Nonproliferation and Disarmament Challenges of Naval Nuclear Propulsion"
• August 3, 2017, "Nuclear Dynamics in a Multipolar Strategic Ballistic Missile Defense World"
• April 6, 2017, "Life-of-the-Ship Reactors and Accelerated Testing of Naval Propulsion Fuels and Reactors"
• December 5, 2016, "France’s Choice for Naval Nuclear Propulsion: Why Low-Enriched Uranium Was Chosen"
• January 27, 2014: "Negotiated Cuts: A New Nuclear Weapons Treaty Is Not The Only Option"

Leadership

Staff

(as of April 14, 2019)

Steven Aftergood - Director of the Government Secrecy Project, as well as editor of Secrecy News

Hans Kristensen - Director of the Nuclear Information Project

Pia Ulrich - International Nuclear Policy Analyst

Frankie Guarini - Membership, Marketing, and Communications Manager

Ali Nouri - President

Michael Fisher - Senior Fellow

Andrew Choi - Senior Fellow serving in the Office of the President at the World Bank

Adam Mount - Director of Defense Posture Project

The Federation of American Scientists is led by a Board of Directors made up of renowned members of the science, business and academic communities.

Staff Credentials

• Dr. Ali Nouri acquired his B.A. in Biology from Reed College and a Ph. D. in Molecular Biology from Princeton. Prior to becoming president of the Federation of American Scientist he served as a legislative director and national security advisor to a U.S senator Al Franken where he oversaw the senator’s legislative team. Later in 2008 he joined Senator Jim Webb’s and worked as an advisor related to science, energy and the environment. Dr. Nouri was also selected to take part in the New Voices project because of his leadership in science, engineering and medicine.
• Steven Aftergood holds a B.Sc. in electrical engineering from UCLA that he acquired in 1977. He joined the Federation of American Scientist staff in 1989 and from 1992-1998 he was a part of the Aeronautics and Space Engineering Board of the National Research Council. In 1997 Steven Aftergood was the plaintiff in a Freedom of Information Act lawsuit against the CIA which lead to the declassification of the total intelligence budget for the first time and again in 2006 he won another lawsuit against the National Reconnaissance Office for the release of their budget records. Currently he directs the FAS project on Government Secrecy to lessen the national security secrecy and promoting more public access to government information and records.
• Hans M. Kristensen was a Senior Researcher for the Nuclear Information Unit of Greenpeace International in Washington D.C from 1991 to 1996. In 1997-1998 Kristensen served as a Special Advisor to the Danish Ministry of Defense and from 1998 to 2002 he guided the Nuclear Strategy Project at Berkeley, CA. From 2002 to 2005 he was a consultant to the nuclear program for the Natural Resources Defense Council in Washington, D.C where he studied nuclear weapon issues and co-authored on multiple published articles and wrote his own report “U.S. Nuclear Weapons in Europe”. Kristensen was also co-author of the “Nuclear Notebook” column which is referenced as the most accurate source of information on nuclear weapons and facilities.
• Adam Mount has a PhD in government from Georgetown University and has been published by multiple media sources including Foreign Affairs, Survival and Democracy to name a few. He has previously worked as a fellow at the Stanton Nuclear Security on the Council on Foreign Relations and was director of the CFR Independent Task Force on US Policy toward North Korea in 2015-2016.
• Dr. Michael A. Fisher holds a Senior Fellow position for the Federation of American Scientists. Fisher earned a B.S. in Biology at that The College of New Jersey and obtained a Ph. D in Molecular Biology from Princeton University. According to his Linkedin, Fisher joined the FAS in January 2019. Before joining the Federation of American Scientists, Fisher contributed to several different organizations such as: working as a Field Director for the Welle for Congress campaign in New Jersey from March 2018-November 2018, holding title of president and Board Member of the Madison Commons Condominium Association, Inc from February 2015- November 2018, working as a Post Doctoral Fellow at Rutgers University from March 2015- March 2018 and more. Fisher is an expert in infectious disease research, biofuels, synthetic biology, protein engineering, and molecular biology. Fisher has been published in 9 different journals, including an article published in Nature called "Testing the Waters". On his LinkedIn, he has stated his summary as "I believe science and engineering research, STEAM education, and public engagement are essential for advancing our society in a more positive direction, and I am pursuing these threads as a Senior Fellow at the Federation of American Scientists".
• Andrew Choi has a BSE from Princeton University in Operation Research and Financial Engineering. He was a part of an investment team at Insight Venture Partners in New York with a focus on software. Previous to his work at FAS Andrew was the CTO and co-founder of Predata, an AI startup that developed an analytic platform that helps predict geopolitical events and risks. He was also the co-founder of Doceoware, built for open online courses. Currently at the Federation of American Scientists he serves the Office of the President at the World Bank focusing on its Famine Action Mechanism (FAM) to help predict global crises and more economically provide aid and resources to affected areas.
• Pia Ulrich has a degree in International and Comparative Law from the University of Osnabrueck and a masters degree in Security Policy Studies from the George Washington University. Ulrich serves as an International Nuclear Policy Analyst and has since August 2013. Pia Ulrich also served as an Advisory Board Member for the William J. Perry Project on Nuclear Weapons Disarmament from June 2003- September 2013.
• Christopher Bidwell received a BA in Political Science from San Diego State University, a MA in National Security Studies and International Relations from the Naval War College, and a JD in Law from Thomas Jefferson School of Law. Bidwell retired from the U.S. Navy having served as a National Security Counselor and the Middle East Desk Officer at the Defense Threat Reduction Agency (DTRA). Bidwell also serves as an active member of the California Bar and an Interest Group for the American Society of International Law.

Blog Sites

Secrecy News Blog

The Secrecy News Blog (ISSN 1939-1986) is a publication of the Federation of American Scientists project on government secrecy. The secrecy blog provides readers with informal coverage of new developments in secrecy, security and intelligence policies, as well as links to new acquisitions on the FAS website. Typically, the blog is updated with a new publication two to three times a week, or as events arise. In addition to the public blogging page, secrecy news is available if one wishes to subscribe to their emails. Archived issues are available on their website, with articles dating back to September 2000.

Strategic Security Blog

The Strategic Security Blog covers national and international security issues.