Yttrium

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Yttrium,  ₃₉Y

Yttrium
Pronunciation	/ˈɪtriəm/ ​(IT-ree-əm)
Appearance	silvery white
Standard atomic weight Ar, std(Y)	88.905
Yttrium 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 Sc ↑ Y ↓ La strontium ← yttrium → zirconium
Atomic number (Z)	39
Group	group 3
Period	period 5
Block	d-block
Element category	Transition metal
Electron configuration	[Kr] 4d1 5s2
Electrons per shell	2, 8, 18, 9, 2
Physical properties
Phase at STP	solid
Melting point	1799 K ​(1526 °C, ​2779 °F)
Boiling point	3203 K ​(2930 °C, ​5306 °F)
Density (near r.t.)	4.472 g/cm3
when liquid (at m.p.)	4.24 g/cm3
Heat of fusion	11.42 kJ/mol
Heat of vaporization	363 kJ/mol
Molar heat capacity	26.53 J/(mol·K)
Vapor pressure P (Pa) 1 10 100 1 k 10 k 100 k at T (K) 1883 2075 (2320) (2627) (3036) (3607)
Atomic properties
Oxidation states	+1, +2, +3 (a weakly basic oxide)
Electronegativity	Pauling scale: 1.22
Ionization energies	1st: 600 kJ/mol 2nd: 1180 kJ/mol 3rd: 1980 kJ/mol
Atomic radius	empirical: 180 pm
Covalent radius	190±7 pm
Spectral lines of yttrium
Other properties
Natural occurrence	primordial
Crystal structure	​hexagonal close-packed (hcp)
Speed of sound thin rod	3300 m/s (at 20 °C)
Thermal expansion	α, poly: 10.6 µm/(m·K) (at r.t.)
Thermal conductivity	17.2 W/(m·K)
Electrical resistivity	α, poly: 596 nΩ·m (at r.t.)
Magnetic ordering	paramagnetic
Magnetic susceptibility	+2.15·10−6 cm3/mol (2928 K)
Young's modulus	63.5 GPa
Shear modulus	25.6 GPa
Bulk modulus	41.2 GPa
Poisson ratio	0.243
Brinell hardness	200–589 MPa
CAS Number	7440-65-5
History
Naming	after Ytterby (Sweden) and its mineral ytterbite (gadolinite)
Discovery	Johan Gadolin (1794)
First isolation	Heinrich Rose (1843)
Main isotopes of yttrium
Iso­tope Abun­dance Half-life (t1/2) Decay mode Pro­duct 87Y syn 3.4 d ε 87Sr γ – 88Y syn 106.6 d ε 88Sr γ – 89Y 100% stable 90Y syn 2.7 d β− 90Zr γ – 91Y syn 58.5 d β− 91Zr γ –

Yttrium is a chemical element with the symbol Y and atomic number 39. It is a silvery-metallic transition metal chemically similar to the lanthanides and has often been classified as a "rare-earth element". Yttrium is almost always found in combination with lanthanide elements in rare-earth minerals, and is never found in nature as a free element. ⁸⁹Y is the only stable isotope, and the only isotope found in the Earth's crust.

In 1787, Carl Axel Arrhenius found a new mineral near Ytterby in Sweden and named it ytterbite, after the village. Johan Gadolin discovered yttrium's oxide in Arrhenius' sample in 1789, and Anders Gustaf Ekeberg named the new oxide yttria. Elemental yttrium was first isolated in 1828 by Friedrich Wöhler.

The most important uses of yttrium are LEDs and phosphors, particularly the red phosphors in television set cathode ray tube (CRT) displays. Yttrium is also used in the production of electrodes, electrolytes, electronic filters, lasers, superconductors, various medical applications, and tracing various materials to enhance their properties.

Yttrium has no known biological role. Exposure to yttrium compounds can cause lung disease in humans.

Characteristics

Properties

Yttrium is a soft, silver-metallic, lustrous and highly crystalline transition metal in group 3. As expected by periodic trends, it is less electronegative than its predecessor in the group, scandium, and less electronegative than the next member of period 5, zirconium; additionally, it is more electronegative to its successor in its group, lanthanum, surpassing in electronegativity to the later lanthanides due to the lanthanide contraction. Yttrium is the first d-block element in the fifth period.

The pure element is relatively stable in air in bulk form, due to passivation of a protective oxide (Y
₂O
₃) film that forms on the surface. This film can reach a thickness of 10 µm when yttrium is heated to 750 °C in water vapor. When finely divided, however, yttrium is very unstable in air; shavings or turnings of the metal can ignite in air at temperatures exceeding 400 °C. Yttrium nitride (YN) is formed when the metal is heated to 1000 °C in nitrogen.

Similarity to the lanthanides

The similarities of yttrium to the lanthanides are so strong that the element has historically been grouped with them as a rare-earth element, and is always found in nature together with them in rare-earth minerals. Chemically, yttrium resembles those elements more closely than its neighbor in the periodic table, scandium, and if physical properties were plotted against atomic number, it would have an apparent number of 64.5 to 67.5, placing it between the lanthanides gadolinium and erbium.

It often also falls in the same range for reaction order, resembling terbium and dysprosium in its chemical reactivity. Yttrium is so close in size to the so-called 'yttrium group' of heavy lanthanide ions that in solution, it behaves as if it were one of them. Even though the lanthanides are one row farther down the periodic table than yttrium, the similarity in atomic radius may be attributed to the lanthanide contraction.

One of the few notable differences between the chemistry of yttrium and that of the lanthanides is that yttrium is almost exclusively trivalent, whereas about half the lanthanides can have valences other than three; nevertheless, only for four of the fifteen lanthanides are these other valences important in aqueous solution (Ce^IV, Sm^II, Eu^II, and Yb^II).

Compounds and reactions

Left: Soluble yttrium salts reacts with carbonate, forming white precipitate yttrium carbonate. Right: Yttrium carbonate is soluble in excess alkali metal carbonate solution

 

As a trivalent transition metal, yttrium forms various inorganic compounds, generally in the oxidation state of +3, by giving up all three of its valence electrons. A good example is yttrium(III) oxide (Y
₂O
₃), also known as yttria, a six-coordinate white solid.

Yttrium forms a water-insoluble fluoride, hydroxide, and oxalate, but its bromide, chloride, iodide, nitrate and sulfate are all soluble in water. The Y³⁺ ion is colorless in solution because of the absence of electrons in the d and f electron shells.

Water readily reacts with yttrium and its compounds to form Y
₂O
₃. Concentrated nitric and hydrofluoric acids do not rapidly attack yttrium, but other strong acids do.

With halogens, yttrium forms trihalides such as yttrium(III) fluoride (YF
₃), yttrium(III) chloride (YCl
₃), and yttrium(III) bromide (YBr
₃) at temperatures above roughly 200 °C. Similarly, carbon, phosphorus, selenium, silicon and sulfur all form binary compounds with yttrium at elevated temperatures.

Organoyttrium chemistry is the study of compounds containing carbon–yttrium bonds. A few of these are known to have yttrium in the oxidation state 0. (The +2 state has been observed in chloride melts, and +1 in oxide clusters in the gas phase.) Some trimerization reactions were generated with organoyttrium compounds as catalysts. These syntheses use YCl
₃ as a starting material, obtained from Y
₂O
₃ and concentrated hydrochloric acid and ammonium chloride.

Hapticity is a term to describe the coordination of a group of contiguous atoms of a ligand bound to the central atom; it is indicated by the Greek character eta, η. Yttrium complexes were the first examples of complexes where carboranyl ligands were bound to a d⁰-metal center through a η⁷-hapticity. Vaporization of the graphite intercalation compounds graphite–Y or graphite–Y
₂O
₃ leads to the formation of endohedral fullerenes such as Y@C₈₂.^[7] Electron spin resonance studies indicated the formation of Y³⁺ and (C₈₂)³⁻ ion pairs.^[7] The carbides Y₃C, Y₂C, and YC₂ can be hydrolyzed to form hydrocarbons.

Isotopes and nucleosynthesis

Yttrium in the Solar System was created through stellar nucleosynthesis, mostly by the s-process (≈72%), but also by the r-process (≈28%). The r-process consists of rapid neutron capture of lighter elements during supernova explosions. The s-process is a slow neutron capture of lighter elements inside pulsating red giant stars.

Mira is an example of the type of red giant star where most of the yttrium in the solar system was created

 

Yttrium isotopes are among the most common products of the nuclear fission of uranium in nuclear explosions and nuclear reactors. In the context of nuclear waste management, the most important isotopes of yttrium are ⁹¹Y and ⁹⁰Y, with half-lives of 58.51 days and 64 hours, respectively. Though ⁹⁰Y has a short half-life, it exists in secular equilibrium with its long-lived parent isotope, strontium-90 (⁹⁰Sr) with a half-life of 29 years.

All group 3 elements have an odd atomic number, and therefore few stable isotopes. Scandium has one stable isotope, and yttrium itself has only one stable isotope, ⁸⁹Y, which is also the only isotope that occurs naturally. However, the lanthanide rare earths contain elements of even atomic number and many stable isotopes. Yttrium-89 is thought to be more abundant than it otherwise would be, due in part to the s-process, which allows enough time for isotopes created by other processes to decay by electron emission (neutron → proton). Such a slow process tends to favor isotopes with atomic mass numbers (A = protons + neutrons) around 90, 138 and 208, which have unusually stable atomic nuclei with 50, 82, and 126 neutrons, respectively. ⁸⁹Y has a mass number close to 90 and has 50 neutrons in its nucleus. 

At least 32 synthetic isotopes of yttrium have been observed, and these range in atomic mass number from 76 to 108. The least stable of these is ¹⁰⁶Y with a half-life of >150 ns (⁷⁶Y has a half-life of >200 ns) and the most stable is ⁸⁸Y with a half-life of 106.626 days. Apart from the isotopes ⁹¹Y, ⁸⁷Y, and ⁹⁰Y, with half-lives of 58.51 days, 79.8 hours, and 64 hours, respectively, all the other isotopes have half-lives of less than a day and most of less than an hour.

Yttrium isotopes with mass numbers at or below 88 decay primarily by positron emission (proton → neutron) to form strontium (Z = 38) isotopes. Yttrium isotopes with mass numbers at or above 90 decay primarily by electron emission (neutron → proton) to form zirconium (Z = 40) isotopes. Isotopes with mass numbers at or above 97 are also known to have minor decay paths of β⁻ delayed neutron emission.

Yttrium has at least 20 metastable ("excited") isomers ranging in mass number from 78 to 102. Multiple excitation states have been observed for ⁸⁰Y and ⁹⁷Y. While most of yttrium's isomers are expected to be less stable than their ground state, ^78mY, ^84mY, ^85mY, ^96mY, ^98m1Y, ^100mY, and ^102mY have longer half-lives than their ground states, as these isomers decay by beta decay rather than isomeric transition.

History

In 1787, army lieutenant and part-time chemist Carl Axel Arrhenius found a heavy black rock in an old quarry near the Swedish village of Ytterby (now part of the Stockholm Archipelago). Thinking that it was an unknown mineral containing the newly discovered element tungsten, he named it ytterbite and sent samples to various chemists for analysis.

Johan Gadolin discovered yttrium oxide

 

Johan Gadolin at the University of Åbo identified a new oxide (or "earth") in Arrhenius' sample in 1789, and published his completed analysis in 1794. Anders Gustaf Ekeberg confirmed the identification in 1797 and named the new oxide yttria. In the decades after Antoine Lavoisier developed the first modern definition of chemical elements, it was believed that earths could be reduced to their elements, meaning that the discovery of a new earth was equivalent to the discovery of the element within, which in this case would have been yttrium.

In 1843, Carl Gustaf Mosander found that samples of yttria contained three oxides: white yttrium oxide (yttria), yellow terbium oxide (confusingly, this was called 'erbia' at the time) and rose-colored erbium oxide (called 'terbia' at the time). A fourth oxide, ytterbium oxide, was isolated in 1878 by Jean Charles Galissard de Marignac. New elements were later isolated from each of those oxides, and each element was named, in some fashion, after Ytterby, the village near the quarry where they were found. In the following decades, seven other new metals were discovered in "Gadolin's yttria". Since yttria was found to be a mineral and not an oxide, Martin Heinrich Klaproth renamed it gadolinite in honor of Gadolin.

Friedrich Wöhler mistakenly thought he had isolated the metal in 1828 from a volatile chloride he supposed to be yttrium chloride, but Heinrich Rose proved otherwise in 1843 and correctly isolated the element himself that year. 

Until the early 1920s, the chemical symbol Yt was used for the element, after which Y came into common use.

In 1987, yttrium barium copper oxide was found to achieve high-temperature superconductivity. It was only the second material known to exhibit this property, and it was the first known material to achieve superconductivity above the (economically important) boiling point of nitrogen.

Occurrence

Xenotime crystals contain yttrium

Abundance

Yttrium is found in most rare-earth minerals, it is found in some uranium ores, but is never found in the Earth's crust as a free element. About 31 ppm of the Earth's crust is yttrium, making it the 28th most abundant element, 400 times more common than silver. Yttrium is found in soil in concentrations between 10 and 150 ppm (dry weight average of 23 ppm) and in sea water at 9 ppt. Lunar rock samples collected during the American Apollo Project have a relatively high content of yttrium.

Yttrium has no known biological role, though it is found in most, if not all, organisms and tends to concentrate in the liver, kidney, spleen, lungs, and bones of humans. Normally, as little as 0.5 milligrams is found in the entire human body; human breast milk contains 4 ppm. Yttrium can be found in edible plants in concentrations between 20 ppm and 100 ppm (fresh weight), with cabbage having the largest amount. With as much as 700 ppm, the seeds of woody plants have the highest known concentrations.

As of April 2018 there are reports of the discovery of very large reserves of rare-earth elements on a tiny Japanese island. Minami-Torishima Island, also known as Marcus Island, is described as having "tremendous potential" for rare-earth elements and yttrium (REY), according to a study published in Scientific Reports. "This REY-rich mud has great potential as a rare-earth metal resource because of the enormous amount available and its advantageous mineralogical features," the study reads. The study shows that more than 16 million tons of rare-earth elements could be "exploited in the near future." Including ytrrium (Y), which is used in products like camera lenses and mobile phone screens, the rare-earth elements found are: Europium (EU), Terbium (Tb) and Dysprosium (Dy).

Production

Since yttrium is chemically so similar to the lanthanides, it occurs in the same ores (rare-earth minerals) and is extracted by the same refinement processes. A slight distinction is recognized between the light (LREE) and the heavy rare-earth elements (HREE), but the distinction is not perfect. Yttrium is concentrated in the HREE group because of its ion size, though it has a lower atomic mass.

A piece of yttrium. Yttrium is difficult to separate from other rare-earth elements.

Rare-earth elements (REEs) come mainly from four sources:

• Carbonate and fluoride containing ores such as the LREE bastnäsite ([(Ce, La, etc.)(CO₃)F]) contain an average of 0.1% of yttrium compared to the 99.9% for the 16 other REEs. The main source for bastnäsite from the 1960s to the 1990s was the Mountain Pass rare earth mine in California, making the United States the largest producer of REEs during that period. The name "bastnäsite" is actually a group name, and the Levinson suffix is used in the correct mineral names, e.g., bästnasite-(Y) has Y as a prevailing element.
• Monazite ([(Ce, La, etc.)PO₄]), which is mostly phosphate, is a placer deposit of sand created by the transportation and gravitational separation of eroded granite. Monazite as a LREE ore contains 2% (or 3%) yttrium. The largest deposits were found in India and Brazil in the early 20th century, making those two countries the largest producers of yttrium in the first half of that century. Of the monazite group, the Ce-dominant member, monazite-(Ce), is the most common one.
• Xenotime, a REE phosphate, is the main HREE ore containing as much as 60% yttrium as yttrium phosphate (YPO₄). This applies to xenotime-(Y). The largest mine is the Bayan Obo deposit in China, making China the largest exporter for HREE since the closure of the Mountain Pass mine in the 1990s.
• Ion absorption clays or Lognan clays are the weathering products of granite and contain only 1% of REEs. The final ore concentrate can contain as much as 8% yttrium. Ion absorption clays are mostly in southern China. Yttrium is also found in samarskite and fergusonite (which also stand for group names).

One method for obtaining pure yttrium from the mixed oxide ores is to dissolve the oxide in sulfuric acid and fractionate it by ion exchange chromatography. With the addition of oxalic acid, the yttrium oxalate precipitates. The oxalate is converted into the oxide by heating under oxygen. By reacting the resulting yttrium oxide with hydrogen fluoride, yttrium fluoride is obtained. When quaternary ammonium salts are used as extractants, most yttrium will remain in the aqueous phase. When the counter-ion is nitrate, the light lanthanides are removed, and when the counter-ion is thiocyanate, the heavy lanthanides are removed. In this way, yttrium salts of 99.999% purity are obtained. In the usual situation, where yttrium is in a mixture that is two-thirds heavy-lanthanide, yttrium should be removed as soon as possible to facilitate the separation of the remaining elements. 

Annual world production of yttrium oxide had reached 600 tonnes by 2001; by 2014 it had increased to 7,000 tons. Global reserves of yttrium oxide were estimated in 2014 to be more than 500,000 tons. The leading countries for these reserves included Australia, Brazil, China, India, and the United States. Only a few tonnes of yttrium metal are produced each year by reducing yttrium fluoride to a metal sponge with calcium magnesium alloy. The temperature of an arc furnace of greater than 1,600 °C is sufficient to melt the yttrium.

Applications

Consumer

Yttrium is one of the elements that was used to make the red color in CRT televisions

 

The red component of color television cathode ray tubes is typically emitted from a yttria (Y
₂O
₃) or yttrium oxide sulfide (Y
₂O
₂S) host lattice doped with europium (III) cation (Eu³⁺) phosphors. The red color itself is emitted from the europium while the yttrium collects energy from the electron gun and passes it to the phosphor. Yttrium compounds can serve as host lattices for doping with different lanthanide cations. Tb³⁺ can be used as a doping agent to produce green luminescence. As such yttrium compounds such as yttrium aluminium garnet (YAG) are useful for phosphors and are an important component of white LEDs.

Yttria is used as a sintering additive in the production of porous silicon nitride. It is used as a common starting material for material science and for producing other compounds of yttrium. 

Yttrium compounds are used as a catalyst for ethylene polymerization. As a metal, yttrium is used on the electrodes of some high-performance spark plugs. Yttrium is used in gas mantles for propane lanterns as a replacement for thorium, which is radioactive.

Currently under development is yttrium-stabilized zirconia as a solid electrolyte and as an oxygen sensor in automobile exhaust systems.

Garnets

Nd:YAG laser rod 0.5 cm in diameter

 

Yttrium is used in the production of a large variety of synthetic garnets, and yttria is used to make yttrium iron garnets (Y
₃Fe
₅O
₁₂, also "YIG"), which are very effective microwave filters which were recently shown to have magnetic interactions more complex and longer-ranged than understood over the previous four decades. Yttrium, iron, aluminium, and gadolinium garnets (e.g. Y₃(Fe,Al)₅O₁₂ and Y₃(Fe,Ga)₅O₁₂) have important magnetic properties. YIG is also very efficient as an acoustic energy transmitter and transducer. Yttrium aluminium garnet (Y
₃Al
₅O
₁₂ or YAG) has a hardness of 8.5 and is also used as a gemstone in jewelry (simulated diamond). Cerium-doped yttrium aluminium garnet (YAG:Ce) crystals are used as phosphors to make white LEDs.

YAG, yttria, yttrium lithium fluoride (LiYF
₄), and yttrium orthovanadate (YVO
₄) are used in combination with dopants such as neodymium, erbium, ytterbium in near-infrared lasers. YAG lasers can operate at high power and are used for drilling and cutting metal. The single crystals of doped YAG are normally produced by the Czochralski process.

Material enhancer

Small amounts of yttrium (0.1 to 0.2%) have been used to reduce the grain sizes of chromium, molybdenum, titanium, and zirconium. Yttrium is used to increase the strength of aluminium and magnesium alloys. The addition of yttrium to alloys generally improves workability, adds resistance to high-temperature recrystallization, and significantly enhances resistance to high-temperature oxidation (see graphite nodule discussion below).

Yttrium can be used to deoxidize vanadium and other non-ferrous metals. Yttria stabilizes the cubic form of zirconia in jewelry.

Yttrium has been studied as a nodulizer in ductile cast iron, forming the graphite into compact nodules instead of flakes to increase ductility and fatigue resistance. Having a high melting point, yttrium oxide is used in some ceramic and glass to impart shock resistance and low thermal expansion properties. Those same properties make such glass useful in camera lenses.

Medical

The radioactive isotope yttrium-90 is used in drugs such as Yttrium Y 90-DOTA-tyr3-octreotide and Yttrium Y 90 ibritumomab tiuxetan for the treatment of various cancers, including lymphoma, leukemia, liver, ovarian, colorectal, pancreatic and bone cancers. It works by adhering to monoclonal antibodies, which in turn bind to cancer cells and kill them via intense β-radiation from the yttrium-90.

A technique called radioembolization is used to treat hepatocellular carcinoma and liver metastasis. Radioembolization is a low toxicity, targeted liver cancer therapy that uses millions of tiny beads made of glass or resin containing radioactive yttrium-90. The radioactive microspheres are delivered directly to the blood vessels feeding specific liver tumors/segments or lobes. It is minimally invasive and patients can usually be discharged after a few hours. This procedure may not eliminate all tumors throughout the entire liver, but works on one segment or one lobe at a time and may require multiple procedures.

Also see Radioembolization in the case of combined cirrhosis and Hepatocellular carcinoma.

Needles made of yttrium-90, which can cut more precisely than scalpels, have been used to sever pain-transmitting nerves in the spinal cord, and yttrium-90 is also used to carry out radionuclide synovectomy in the treatment of inflamed joints, especially knees, in sufferers of conditions such as rheumatoid arthritis.

A neodymium-doped yttrium-aluminium-garnet laser has been used in an experimental, robot-assisted radical prostatectomy in canines in an attempt to reduce collateral nerve and tissue damage, and erbium-doped lasers are coming into use for cosmetic skin resurfacing.

Superconductors

YBCO superconductor

 

Yttrium is a key ingredient in the yttrium barium copper oxide (YBa₂Cu₃O₇, aka 'YBCO' or '1-2-3') superconductor developed at the University of Alabama and the University of Houston in 1987. This superconductor is notable because the operating superconductivity temperature is above liquid nitrogen's boiling point (77.1 K). Since liquid nitrogen is less expensive than the liquid helium required for metallic superconductors, the operating costs for applications would be less.

The actual superconducting material is often written as YBa₂Cu₃O_7–d, where d must be less than 0.7 for superconductivity. The reason for this is still not clear, but it is known that the vacancies occur only in certain places in the crystal, the copper oxide planes, and chains, giving rise to a peculiar oxidation state of the copper atoms, which somehow leads to the superconducting behavior. 

The theory of low temperature superconductivity has been well understood since the BCS theory of 1957. It is based on a peculiarity of the interaction between two electrons in a crystal lattice. However, the BCS theory does not explain high temperature superconductivity, and its precise mechanism is still a mystery. What is known is that the composition of the copper-oxide materials must be precisely controlled for superconductivity to occur.

This superconductor is a black and green, multi-crystal, multi-phase mineral. Researchers are studying a class of materials known as perovskites that are alternative combinations of these elements, hoping to develop a practical high-temperature superconductor.

Precautions

Yttrium currently has no biological role, and it can be highly toxic to humans and other animals.

Water-soluble compounds of yttrium are considered mildly toxic, while its insoluble compounds are non-toxic. In experiments on animals, yttrium and its compounds caused lung and liver damage, though toxicity varies with different yttrium compounds. In rats, inhalation of yttrium citrate caused pulmonary edema and dyspnea, while inhalation of yttrium chloride caused liver edema, pleural effusions, and pulmonary hyperemia.

Exposure to yttrium compounds in humans may cause lung disease. Workers exposed to airborne yttrium europium vanadate dust experienced mild eye, skin, and upper respiratory tract irritation—though this may be caused by the vanadium content rather than the yttrium. Acute exposure to yttrium compounds can cause shortness of breath, coughing, chest pain, and cyanosis. The Occupational Safety and Health Administration (OSHA) limits exposure to yttrium in the workplace to 1 mg/m³ over an 8-hour workday. The National Institute for Occupational Safety and Health (NIOSH) recommended exposure limit (REL) is 1 mg/m³ over an 8-hour workday. At levels of 500 mg/m³, yttrium is immediately dangerous to life and health. Yttrium dust is flammable.

Destruction of cultural heritage by ISIL

From Wikipedia, the free encyclopedia

 

Deliberate destruction and theft of cultural heritage has been conducted by the Islamic State of Iraq and the Levant since 2014 in Iraq, Syria, and to a lesser extent in Libya. The destruction targets various places of worship under ISIL control and ancient historical artifacts. In Iraq, between the fall of Mosul in June 2014 and February 2015, ISIL had plundered and destroyed at least 28 historical religious buildings. Valuable items from some buildings were looted in order to smuggle and sell them to foreigners to finance ISIS activities. By 23 March 2019, ISIL lost most of its territories in the Middle East, having been defeated in Iraq and Syria.

Motivation

ISIL justifies the destruction of cultural heritage sites with its following of Salafism which, according to its followers, places "great importance on establishing tawhid (monotheism)", and "eliminating shirk (polytheism)." While it is often assumed that the group's actions are mindless acts of vandalism, there is an ideological underpinning to the destruction. ISIL views its actions in sites like Palmyra and Nimrud as being in accordance with Sunni Islamic tradition.

Beyond the ideological aspects of the destruction, there are other, more practical, reasons behind ISIL's destruction of historic sites. Grabbing the world's attention is easily done through the destruction of such sites, given the extensive media coverage and international condemnation that comes afterwards. Destroying historic ruins also allows ISIL to wipe the slate clean and to start afresh, leaving no traces of any previous culture or civilization, while also providing an ideal platform for the group to establish its own identity and leave its mark on history. Despite the images showing extreme destruction, ISIL has also been making use of the looted antiquities to finance their activities. Despite the UN's ban on the trade of artifacts looted from Syria since 2011, the group has been smuggling these artifacts out of the Middle East and on to the underground antique markets of Europe and North America.

Destroyed heritage

Prophet Jonah (Nabi Yunus) Mosque in Mosul, pictured in 1999. It was destroyed by ISIL in 2014.

Mosques and shrines

In 2014, media reported destruction of multiple, chiefly Shiite, mosques and shrines throughout Iraq by ISIL. Among them were the Al-Qubba Husseiniya Mosque in Mosul, Sheikh Jawad Al-Sadiq Mosque, Mosque of Arnā’ūt, Mosque of Qado, Mosque of Askar e- Mullah and Saad Bin Aqeel Shrine in Tal Afar, Sufi Ahmed al-Rifai Shrine and tomb and Sheikh Ibrahim shrine in Mahlabiya District and the so-called Tomb of the Girl (Qabr al-Bint) in Mosul. The Tomb of the Girl, reputed to honour a girl who died of a broken heart, was actually believed to be the tomb of medieval scholar Ali ibn al-Athir.

In June 2014, ISIL bulldozed the two buildings in the complex of the shrine of Fathi al-Ka'en.

On 24 September 2014, the Arba'een Wali Mosque and Shrine in Tikrit, containing forty tombs from the Umar era, was blown up. On 26 February 2015 ISIL blew up the 12th century Green Mosque in central Mosul.

In Mosul, ISIL also targeted several tombs with shrines built over them. In July 2014, ISIL destroyed one of the tombs of prophet Daniel (located in Mosul) by planted explosives. On 24 July 2014, the tomb and mosque of the prophet Jonah was destroyed with explosives. On 27 July, ISIL destroyed the tomb of Prophet Jirjis (George).

On 25 July 2014, the 13th-century shrine of Imam Awn al-Din in Mosul, one of the few structures to have survived the 13th-century Mongol invasion, was destroyed by ISIL. The destruction was mostly carried out with explosive devices, but in some cases bulldozers were used.

In March 2015, ISIL reportedly bulldozed to the ground the Hamu Al-Qadu Mosque in Mosul, dating back to 1880. The Hamu-Al-Qadu mosque contained an earlier tomb of Ala-al-din Ibn Abdul Qadir Gilani. In the same year ISIL ordered the removal of all decorative elements and frescoes from mosques in Mosul, even those containing Quranic verses that mention Allah. They were regarded by ISIL as "an erroneous form of creativity, contradicting the basics of sharia." At least one imam in Mosul opposing that order was shot to death.

Leaning minaret of the Great Mosque of Al-nuri. Destroyed by ISIL on 22 June 2017 during the Battle of Mosul.

 

ISIL also destroyed Sufi shrines near Tripoli, Libya, in March 2015. The shrines were destroyed by sledgehammers and bulldozers.

In June 2015, it was announced that ISIL had blown up the ancient tombs of Mohammed bin Ali and Nizar Abu Bahaaeddine, located close to the ruins of Palmyra.

In 2016, ISIL destroyed the Minaret of Anah located in Al Anbar Province, which dates back to the Abbasid era. The minaret was only rebuilt in 2013 after the destruction by an unknown perpetrator in 2006.

In 2017, ISIL destroyed the Great Mosque of al-Nuri and its leaning minaret. This was the mosque where ISIL leader Abu Bakr al-Baghdadi declared the establishment of the Islamic State caliphate three years prior.

Churches and monasteries

Dair Mar Elia monastery, which was destroyed sometime between late August and September 2014

 

In June 2014, it was reported that ISIL elements had been instructed to destroy all churches in Mosul. Since then, most churches within the city have been destroyed.

• The Virgin Mary Church was destroyed with several improvised explosive devices in July 2014.
• Dair Mar Elia, the oldest monastery in Iraq, was demolished sometime between late August and September 2014. The destruction went unreported until January 2016.
• The Al-Tahera Church, built in the early 20th century, was possibly blown up in early February 2015. However, there is no evidence that the church was actually destroyed.
• St Markourkas Church, a 10th-century Chaldean Catholic church, was destroyed on 9 March 2015, according to the Iraqi government official Dureid Hikmat Tobia. A nearby cemetery was also bulldozed.
• Another church, which was reportedly "thousands of years" old, was blown up in July 2015. According to Kurdish sources, four children were inadvertently killed when the church was destroyed.
• The Sa'a Qadima Church, which was built in 1872, was blown up in April 2016.

The Sa'a Qadima Church in Mosul, blown up in April 2016

 

ISIL also blew up or demolished a number of other churches elsewhere in Iraq or in Syria. The Armenian Genocide Memorial Church in Deir ez-Zor, Syria was blown up by ISIL militants on 21 September 2014.

On 24 September 2014 ISIL militants destroyed with improvised explosive devices the 7th-century Green Church (also known as St Ahoadamah Church) belonging to the Assyrian Church of the East in Tikrit.

The Mar Behnam Monastery in Khidr Ilyas near Bakhdida, Iraq was destroyed by ISIL in March 2015.

As of 5 April 2015, ISIL destroyed the Assyrian Christian Virgin Mary Church on Easter Sunday in the Syrian town of Tel Nasri. "As the 'joint forces' of Kurdish People's Protection Units and local Assyrian fighters attempted to enter the town", ISIL set off the explosives destroying what remained of the church. ISIL had controlled the church since 7 March 2015.

On 21 August 2015, the historic Monastery of St. Elian near Al-Qaryatayn in the Homs Governorate was destroyed by ISIL.

Ancient and medieval sites

The Tal Afar Citadel, which was partially destroyed in December 2014

 

In May 2014, ISIL members smashed a 3,000-year-old neo-Assyrian statue from Tel Ajaja. Later reports indicated that over 40% of the artifacts at Tel Ajaja (Saddikanni) were looted by ISIS.

Parts of the Tal Afar Citadel were blown up by ISIL in December 2014, causing extensive damage.

In January 2015, ISIL reportedly destroyed large parts of the Nineveh Wall in al-Tahrir neighborhood of Mosul. Further parts of the walls, including the Mashka and Adad Gate, were blown up in April 2016.

In the Syrian city of Raqqa, ISIL publicly ordered the bulldozing of a colossal ancient Assyrian gateway lion sculpture from the 8th century BC. Another lion statue was also destroyed. Both statues originated from the Arslan Tash archaeological site. The destruction was published in the ISIL magazine, Dabiq. Among the lost statues are those of Mulla Uthman al-Mawsili, of a woman carrying an urn, and of Abu Tammam.

On 26 February 2015, ISIL released a video showing the destruction of various ancient artifacts in the Mosul Museum. The affected artifacts originate from the Assyrian era and from the ancient city of Hatra. The video in particular shows the defacement of a granite lamassu statue from the right side of the Nergal Gate by a jackhammer. The statue remained buried until 1941 when heavy rains eroded the soil around the gate and exposed two statues on both sides. Several other defaced items in the museum were claimed to be copies, but this was later rebutted by Iraq's Minister of Culture, Adel Sharshab who said: "Mosul Museum had many ancient artifacts, big and small. None of them were transported to the National Museum of Iraq in Baghdad. Thus, all artifacts destroyed in Mosul are original except for four pieces that were made of gypsum".

Palace of Ashurnasirpal II in Nimrud, pictured in 2007. ISIL reportedly bulldozed the city in March 2015

 

On 5 March 2015, ISIL reportedly started the demolition of Nimrud, an Assyrian city from the 13th century BC. The local palace was bulldozed, while lamassu statues at the gates of the palace of Ashurnasirpal II were smashed. A video showing the destruction of Nimrud was released in April 2015.

On 7 March 2015, Kurdish sources reported that ISIL had begun the bulldozing of Hatra, which has been under threat of demolition after ISIL had occupied the adjacent area. The next day ISIL sacked Dur-Sharrukin, according to a Kurdish official from Mosul, Saeed Mamuzini.

The Iraqi Tourism and Antiquities Ministry launched the related investigation on the same day. On 8 April 2015, the Iraqi Ministry of Tourism reported that ISIL destroyed the remnants of the 12th-century Bash Tapia Castle in Mosul. As of early July 2015, 20% of Iraq's 10,000 archaeological sites has been under ISIL control.

In 2015 the face of the Winged Bull of Nineveh was damaged.

Palmyra

Temple of Bel in Palmyra, which was blown up by ISIL in August 2015

 

Following the capture of Palmyra in Syria, ISIL was reported as not intending to demolish the city's World Heritage Site (while still intending to destroy any statues deemed 'polytheistic'). On 27 May 2015, ISIL released an 87-second video showing parts of the apparently undamaged ancient colonnades, the Temple of Bel and the Roman theatre. On 27 June 2015, however, ISIL demolished the ancient Lion of Al-lāt statue in Palmyra. Several other statues from Palmyra reportedly confiscated from a smuggler were also destroyed by ISIL. On 23 August 2015, it was reported that ISIL had blown up the 1st-century Temple of Baalshamin. On 30 August 2015, ISIL demolished the Temple of Bel with explosives. Satellite imagery of the site taken shortly after showed almost nothing remained.

According to the report issued on September 3, 2015 by ASOR Syrian Heritage initiative, ISIL also destroyed seven ancient tower tombs in Palmyra since the end of June over two phases. The last phase of destruction occurred between August 27 and September 2, 2015, including the destruction of the 2nd-century AD Tower of Elahbel, called "the most prominent example of Palmyra's distinct funerary monuments". Earlier, the ancient tombs of Iamliku and Atenaten were also destroyed. The Monumental Arch was also blown up in October.

When Palmyra was recaptured by Syrian government forces in March 2016, retreating ISIL fighters blew up parts of the 13th-century Palmyra Castle, causing extensive damage.

ISIL has also looted and demolished the Parthian/Roman city of Dura-Europos in east of Syria. Nicknamed "the Pompeii of the desert", the city was of particular archaeological significance. 

It was reported on 1 January 2019 that Syrian authorities recovered two Roman-era funerary busts smuggled from Palmyra from an abandoned ISIL site in the al-Suknah countryside.

Hatra

Hatra (Arabic: الحضر al-Ḥaḍr) was an ancient city in the Ninawa Governorate and al-Jazira region of Iraq. A large fortified city and capital of the first Arab Kingdom, Hatra withstood invasions by the Romans in A.D. 116 and 198 thanks to its high, thick walls reinforced by towers. However about 240 ce, the city fell to Shāpūr I (reigned c. 240–272), the ruler of the Persian Sāsānian dynasty, and was destroyed. The remains of the city, especially the temples where Hellenistic and Roman architecture blend with Eastern decorative features, attest to the greatness of its civilization. The city lies 290 km (180 mi) northwest of Baghdad and 110 km (68 mi) southwest of Mosul. On 7 March 2015, various sources including Iraqi officials reported that the militant group Islamic State of Iraq and the Levant (ISIL) had begun demolishing the ruins of Hatra. Video released by ISIL the next month showed destruction of the monuments. The ancient city was recaptured by the Popular Mobilization Forces on 26 April 2017.

Libraries

ISIL has burned or stolen collections of books and papers from various locations, including the Central Library of Mosul (which they rigged with explosives and burned down), the library at the University of Mosul, a Sunni Muslim library, a 265-year-old Latin Church and Monastery of the Dominican Fathers, and the Mosul Museum Library. Some destroyed or stolen works date back to 5000 BC and include "Iraq newspapers dating to the early 20th century, maps and books from the Ottoman Empire, and book collections contributed by about 100 of Mosul’s establishment families." The stated goal is to destroy all non-Islamic books.

Response

On 22 September 2014, the United States Secretary of State John Kerry announced that the Department of State had partnered with the American Schools of Orient Research Cultural Heritage Initiatives to "comprehensively document the condition of, and threats to, cultural heritage sites in Iraq and Syria to assess their future restoration, preservation, and protection needs". In 2014, the UNESCO's Committee for the Protection of Cultural Property in the Event of Armed Conflict condemned at the Ninth Meeting "repeated and deliberate attacks against cultural property... in particular in the Syrian Arab Republic and the Republic of Iraq". UNESCO Director-General Irina Bokova called the destructions in Mosul a violation of the United Nations Security Council Resolution 2199, and the destruction of Nimrud a war crime.

Former Prime Minister of Iraq Nouri al-Maliki reported that the local parliamentary tourism and antiquities committee had "filed complaints with the UN to condemn all ISIL crimes and abuses, including those that affect ancient places of worship". On 28 May 2015, the United Nations General Assembly unanimously passed a resolution, initiated by Germany and Iraq and sponsored by 91 UN member states, stating that ISIL's destruction of cultural heritage may amount to a war crime and urging international measures to halt such acts, which it described as a "tactic of war".

After the Palmyra temple's destruction in August 2015, the Institute for Digital Archaeology (IDA) announced plans to establish a digital record of historical sites and artifacts threatened by ISIL advance. To accomplish this goal, the IDA, in collaboration with UNESCO, will deploy 5,000 3D cameras to partners in the Middle East. The cameras will be used to capture 3D scans of local ruins and relics.

The general director of the Czech National Museum, Michal Lukeš, signed an agreement in June 2017 committing the institution to help Syria save, preserve and conserve much of its cultural and historical heritage damaged by war, including the ancient site of Palmyra; he met with Maamoun Abdulkarim and discussed plans for the works that are said to last until 2019.

In June 2017, The World Monuments Fund (WMF) announced launching a £500,000 scheme to train Syrian refugees near the Syrian-Jordanian border in traditional stone masonry. The aim is teaching them to develop skills necessary to be able to help in restoring cultural heritage sites that have been damaged or destroyed during the Syrian Civil War once peace is restored to Syria.

Minor restorations have already begun: Palmyrene funerary busts of a deceased man and a woman, damaged and defaced by ISIL, were taken from Palmyra, then to Beirut to be sent off to Rome. Italian experts restored the portraits using 3D technology to print resin prosthetics, which were coated with a thick layer of stone dust to blend in with the original stone; the prosthetics were attached to the damaged faces of the busts using strong magnets. The restored pieces are now back in Syria. Abdulkarim said the restoration of the busts "is the first real, visible positive step that the international community has taken to protect Syrian heritage".