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Cerium

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Not to be confused with caesium (also spelled "cesium") or curium.

Cerium, 58Ce
Cerium
Pronunciation/ˈsɪəriəm/ ​(SEER-ee-əm)
Appearancesilvery white
Standard atomic weight Ar°(Ce)
Cerium 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
–
↑
Ce
↓
Th
lanthanum ← cerium → praseodymium
Atomic number (Z)58
Groupf-block groups (no number)
Periodperiod 6
Block  f-block
Electron configuration[Xe] 4f1 5d1 6s2[3]
Electrons per shell2, 8, 18, 19, 9, 2
Physical properties
Phase at STPsolid
Melting point1068 K ​(795 °C, ​1463 °F)
Boiling point3716 K ​(3443 °C, ​6229 °F)
Density (at 20° C)β-Ce: 6.689 g/cm3
γ-Ce: 6.769 g/cm3 [4]
when liquid (at m.p.)6.55 g/cm3
Heat of fusion5.46 kJ/mol
Heat of vaporization398 kJ/mol
Molar heat capacity26.94 J/(mol·K)
Vapor pressure
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 1992 2194 2442 2754 3159 3705
Atomic properties
Oxidation statescommon: +3, +4
+2[5]
ElectronegativityPauling scale: 1.12
Ionization energies
  • 1st: 534.4 kJ/mol
  • 2nd: 1050 kJ/mol
  • 3rd: 1949 kJ/mol
  • (more)
Atomic radiusempirical: 181.8 pm
Covalent radius204±9 pm
Color lines in a spectral range
Spectral lines of cerium
Other properties
Natural occurrenceprimordial
Crystal structureβ-Ce: ​double hexagonal close-packed (dhcp) (hP4)
Lattice constants
Double hexagonal close packed crystal structure for β-Ce: cerium
a = 0.36811 nm
c = 1.1857 nm (at 20 °C)[4]
Crystal structureγ-Ce: ​face-centered cubic (fcc) (cF4)
Lattice constant
Face-centered cubic crystal structure for γ-Ce: cerium
a = 0.51612 nm (at 20 °C)[4]
Thermal expansionβ-Ce: 6.1×10−6/K
γ-Ce: 6.1×10−6/K (at 20 °C)[4]
Thermal conductivity11.3 W/(m⋅K)
Electrical resistivityβ-Ce, poly: 828 nΩ⋅m (at r.t.)
Magnetic orderingparamagnetic[6]
Molar magnetic susceptibilityβ-Ce: +2450.0×10−6 cm3/mol (293 K)[7]
Young's modulusγ-Ce: 33.6 GPa
Shear modulusγ-Ce: 13.5 GPa
Bulk modulusγ-Ce: 21.5 GPa
Speed of sound thin rod2100 m/s (at 20 °C)
Poisson ratioγ-Ce: 0.24
Mohs hardness2.5
Vickers hardness210–470 MPa
Brinell hardness186–412 MPa
CAS Number7440-45-1
History
Namingafter dwarf planet Ceres, itself named after Roman deity of agriculture Ceres
DiscoveryMartin Heinrich Klaproth, Jöns Jakob Berzelius, Wilhelm Hisinger (1803)
First isolationCarl Gustaf Mosander (1838)
Isotopes of cerium
Main isotopes[8] Decay
abun­dance half-life (t1/2) mode pro­duct
134Ce synth 3.16 d ε 134La
136Ce 0.186% stable
138Ce 0.251% stable
139Ce synth 137.640 d ε 139La
140Ce 88.4% stable
141Ce synth 32.501 d β− 141Pr
142Ce 11.1% stable
143Ce synth 33.039 h β− 143Pr
144Ce synth 284.893 d β− 144Pr
 Category: Cerium
| references

Cerium is a chemical element; it has symbol Ce and atomic number 58. It is a soft, ductile, and silvery-white metal that tarnishes when exposed to air. Cerium is the second element in the lanthanide series, and while it often shows the oxidation state of +3 characteristic of the series, it also has a stable +4 state that does not oxidize water. It is considered one of the rare-earth elements. Cerium has no known biological role in humans but is not particularly toxic, except with intense or continued exposure.

Despite always occurring in combination with the other rare-earth elements in minerals such as those of the monazite and bastnäsite groups, cerium is easy to extract from its ores, as it can be distinguished among the lanthanides by its unique ability to be oxidized to the +4 state in aqueous solution. It is the most common of the lanthanides, followed by neodymium, lanthanum, and praseodymium. Its estimated abundance in the Earth's crust is 68 ppm.

Cerium was the first of the lanthanides to be discovered, in Bastnäs, Sweden. It was discovered by Jöns Jakob Berzelius and Wilhelm Hisinger in 1803, and independently by Martin Heinrich Klaproth in Germany in the same year. In 1839 Carl Gustaf Mosander became the first to isolate the metal. Today, cerium and its compounds have a variety of uses: for example, cerium(IV) oxide is used to polish glass and is an important part of catalytic converters. Cerium metal is used in ferrocerium lighters for its pyrophoric properties. Cerium-doped YAG phosphor is used in conjunction with blue light-emitting diodes to produce white light in most commercial white LED light sources.

Characteristics

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Physical

[edit]

Cerium is the second element of the lanthanide series. In the periodic table, it appears between the lanthanides lanthanum to its left and praseodymium to its right, and above the actinide thorium. It is a ductile metal with a hardness similar to that of silver.[9] Its 58 electrons are arranged in the configuration [Xe]4f15d16s2, of which the four outer electrons are valence electrons.[10] The 4f, 5d, and 6s energy levels are very close to each other, and the transfer of one electron to the 5d shell is due to strong interelectronic repulsion in the compact 4f shell. This effect is overwhelmed when the atom is positively ionised; thus Ce2+ on its own has instead the regular configuration [Xe]4f2, although in some solid solutions it may be [Xe]4f15d1.[11] Most lanthanides can use only three electrons as valence electrons, as afterwards the remaining 4f electrons are too strongly bound: cerium is an exception because of the stability of the empty f-shell in Ce4+ and the fact that it comes very early in the lanthanide series, where the nuclear charge is still low enough until neodymium to allow the removal of the fourth valence electron by chemical means.[12]

Cerium has a variable electronic structure. The energy of the 4f electron is nearly the same as that of the outer 5d and 6s electrons that are delocalized in the metallic state, and only a small amount of energy is required to change the relative occupancy of these electronic levels. This gives rise to dual valence states. For example, a volume change of about 10% occurs when cerium is subjected to high pressures or low temperatures. In its high pressure phase (α-Cerium), the 4f electrons are also delocalized and itinerate, as opposed to localized 4f electrons in low pressure phase (γ-Cerium).[13] It appears that the valence changes from about 3 to 4 when it is cooled or compressed.[14]

Chemical properties of the element

[edit]

Like the other lanthanides, cerium metal is a good reducing agent, having standard reduction potential of E⦵ = −2.34 V for the Ce3+/Ce couple.[15] It tarnishes in air, forming a passivating oxide layer like iron rust. A centimeter-sized sample of cerium metal corrodes completely in about a year. More dramatically, metallic cerium can be highly pyrophoric:[16]

Ce + O2 → CeO2

Being highly electropositive, cerium reacts with water. The reaction is slow with cold water but speeds up with increasing temperature, producing cerium(III) hydroxide and hydrogen gas:[17]

2 Ce + 6 H2O → 2 Ce(OH)3 + 3 H2

Allotropes

[edit]
Cerium phase diagram
Phase diagram of cerium

Four allotropic forms of cerium are known to exist at standard pressure and are given the common labels of α to δ:[18]

  • The high-temperature form, δ-cerium, has a bcc (body-centered cubic) crystal structure and exists above 726 °C.
  • The stable form below 726 °C to approximately room temperature is γ-cerium, with an fcc (face-centered cubic) crystal structure.
  • The DHCP (double hexagonal close-packed) form β-cerium is the equilibrium structure approximately from room temperature to −150 °C.
  • The fcc form α-cerium is stable below about −150 °C; it has a density of 8.16 g/cm3.
  • Other solid phases occurring only at high pressures are shown on the phase diagram.
  • Both γ and β forms are quite stable at room temperature, although the equilibrium transformation temperature is estimated at 75 °C.[18]

At lower temperatures the behavior of cerium is complicated by the slow rates of transformation. Transformation temperatures are subject to substantial hysteresis and values quoted here are approximate. Upon cooling below −15 °C, γ-cerium starts to change to β-cerium, but the transformation involves a volume increase and, as more β forms, the internal stresses build up and suppress further transformation.[18] Cooling below approximately −160 °C will start formation of α-cerium but this is only from remaining γ-cerium. β-cerium does not significantly transform to α-cerium except in the presence of stress or deformation.[18] At atmospheric pressure, liquid cerium is more dense than its solid form at the melting point.[9][19][20]

Isotopes

[edit]
Main article: Isotopes of cerium

Naturally occurring cerium is made up of four isotopes: 136Ce (0.19%), 138Ce (0.25%), 140Ce (88.4%), and 142Ce (11.1%). All four are observationally stable, though the light isotopes 136Ce and 138Ce are theoretically expected to undergo double electron capture to isotopes of barium, and the heaviest isotope 142Ce is expected to undergo double beta decay to 142Nd or alpha decay to 138Ba. Thus, 140Ce is the only theoretically stable isotope. None of these decay modes have yet been observed, though the double beta decay of 136Ce, 138Ce, and 142Ce have been experimentally searched for. The current experimental limits for their half-lives are:[21]

136Ce: >3.8×1016 y
138Ce: >5.7×1016 y
142Ce: >5.0×1016 y

All other cerium isotopes are synthetic and radioactive. The most stable of them are 144Ce with a half-life of 284.9 days, 139Ce with a half-life of 137.6 days, and 141Ce with a half-life of 32.5 days. All other radioactive cerium isotopes have half-lives under four days, and most of them have half-lives under ten minutes.[21] The isotopes between 140Ce and 144Ce inclusive occur as fission products of uranium.[21] The primary decay mode of the isotopes lighter than 140Ce is inverse beta decay or electron capture to isotopes of lanthanum, while that of the heavier isotopes is beta decay to isotopes of praseodymium.[21] Some isotopes of neodymium can alpha decay or are predicted to decay to isotopes of cerium.[22]

The rarity of the proton-rich 136Ce and 138Ce is explained by the fact that they cannot be made in the most common processes of stellar nucleosynthesis for elements beyond iron, the s-process (slow neutron capture) and the r-process (rapid neutron capture). This is so because they are bypassed by the reaction flow of the s-process, and the r-process nuclides are blocked from decaying to them by more neutron-rich stable nuclides. Such nuclei are called p-nuclei, and their origin is not yet well understood: some speculated mechanisms for their formation include proton capture as well as photodisintegration.[23] 140Ce is the most common isotope of cerium, as it can be produced in both the s- and r-processes, while 142Ce can only be produced in the r-process. Another reason for the abundance of 140Ce is that it is a magic nucleus, having a closed neutron shell (it has 82 neutrons), and hence it has a very low cross section towards further neutron capture. Although its proton number of 58 is not magic, it is granted additional stability, as its eight additional protons past the magic number 50 enter and complete the 1g7/2 proton orbital.[23] The abundances of the cerium isotopes may differ very slightly in natural sources, because 138Ce and 140Ce are the daughters of the long-lived primordial radionuclides 138La and 144Nd, respectively.[21]

Compounds

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Cerium exists in two main oxidation states, Ce(III) and Ce(IV). This pair of adjacent oxidation states dominates several aspects of the chemistry of this element. Cerium(IV) aqueous solutions may be prepared by reacting cerium(III) solutions with the strong oxidizing agents peroxodisulfate or bismuthate. The value of E⦵(Ce4+/Ce3+) varies widely depending on conditions due to the relative ease of complexation and hydrolysis with various anions, although +1.72 V is representative. Cerium is the only lanthanide which has important aqueous and coordination chemistry in the +4 oxidation state.[15]

Halides

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Cerium forms all four trihalides CeX3 (X = F, Cl, Br, I) usually by reaction of the oxides with the hydrogen halides. The anhydrous halides are pale-colored, paramagnetic, hygroscopic solids. Upon hydration, the trihalides convert to complexes containing aquo complexes [Ce(H2O)8-9]3+. Unlike most lanthanides, Ce forms a tetrafluoride, a white solid. It also forms a bronze-colored diiodide, which has metallic properties.[24] Aside from the binary halide phases, a number of anionic halide complexes are known. The fluoride gives the Ce(IV) derivatives CeF4−8 and CeF2−6. The chloride gives the orange CeCl2−6.[15]

Oxides and chalcogenides

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Cerium(IV) oxide ("ceria") has the fluorite structure, similarly to the dioxides of praseodymium and terbium. Ceria is a nonstoichiometric compound, meaning that the real formula is CeO2−x, where x is about 0.2. Thus, the material is not perfectly described as Ce(IV). Ceria reduces to cerium(III) oxide with hydrogen gas.[25] Many nonstoichiometric chalcogenides are also known, along with the trivalent Ce2Z3 (Z = S, Se, Te). The monochalcogenides CeZ conduct electricity and would better be formulated as Ce3+Z2−e−. While CeZ2 are known, they are polychalcogenides with cerium(III): cerium(IV) derivatives of S, Se, and Te are unknown.[25]

Cerium(IV) complexes

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Ceric ammonium nitrate
Ceric ammonium nitrate

The compound ceric ammonium nitrate (CAN) (NH4)2[Ce(NO3)6] is the most common cerium compound encountered in the laboratory. The six nitrate ligands bind as bidentate ligands. The complex [Ce(NO3)6]2− is 12-coordinate, a high coordination number which emphasizes the large size of the Ce4+ ion. CAN is a popular oxidant in organic synthesis, both as a stoichiometric reagent[26] and as a catalyst.[27] It is inexpensive, stable in air, easily handled, and of low toxicity.[27] It operates by one-electron redox. Cerium nitrates also form 4:3 and 1:1 complexes with 18-crown-6 (the ratio referring to that between the nitrate and the crown ether). Classically, CAN is a primary standard for quantitative analysis.[9][28] Cerium(IV) salts, especially cerium(IV) sulfate, are often used as standard reagents for volumetric analysis in cerimetric titrations.[29]

A white LED in operation
A white LED in operation: the diode produces monochromatic blue light but the Ce:YAG phosphor converts some of it into yellow light; the combination is perceived as white by the human eye.

Due to ligand-to-metal charge transfer, aqueous cerium(IV) ions are orange-yellow.[30] Aqueous cerium(IV) is metastable in water[31] and is a strong oxidizing agent that oxidizes hydrochloric acid to give chlorine gas.[15] In the Belousov–Zhabotinsky reaction, cerium oscillates between the +4 and +3 oxidation states to catalyze the reaction.[32]

Organocerium compounds

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Organocerium chemistry is similar to that of the other lanthanides, often involving complexes of cyclopentadienyl and cyclooctatetraenyl ligands. Cerocene (Ce(C8H8)2) adopts the uranocene molecular structure.[33] The 4f electron in cerocene is poised ambiguously between being localized and delocalized and this compound is considered intermediate-valent.[34] Alkyl, alkynyl, and alkenyl organocerium derivatives are prepared from the transmetallation of the respective organolithium or Grignard reagents, and are more nucleophilic but less basic than their precursors.[35][36]

History

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The dwarf planet Ceres.
The dwarf planet and asteroid Ceres, after which cerium is named
Jöns Jakob Berzelius
Jöns Jakob Berzelius, one of the discoverers of cerium

Cerium was discovered in Bastnäs in Sweden by Jöns Jakob Berzelius and Wilhelm Hisinger, and independently in Germany by Martin Heinrich Klaproth, both in 1803.[37] Cerium was named by Berzelius after the asteroid Ceres, formally 1 Ceres, discovered two years earlier.[37][38] Ceres was initially considered to be a planet at the time. The asteroid is itself named after the Roman goddess Ceres, goddess of agriculture, grain crops, fertility and motherly relationships.[37]

Cerium was originally isolated in the form of its oxide, which was named ceria, a term that is still used. The metal itself was too electropositive to be isolated by then-current smelting technology, a characteristic of rare-earth metals in general. After the development of electrochemistry by Humphry Davy five years later, the earths soon yielded the metals they contained. Ceria, as isolated in 1803, contained all of the lanthanides present in the cerite ore from Bastnäs, Sweden, and thus only contained about 45% of what is now known to be pure ceria. It was not until Carl Gustaf Mosander succeeded in removing lanthana and "didymia" in the late 1830s that ceria was obtained pure. Wilhelm Hisinger was a wealthy mine-owner and amateur scientist, and sponsor of Berzelius. He owned and controlled the mine at Bastnäs, and had been trying for years to find out the composition of the abundant heavy gangue rock (the "Tungsten of Bastnäs", which despite its name contained no tungsten), now known as cerite, that he had in his mine.[38] Mosander and his family lived for many years in the same house as Berzelius, and Mosander was undoubtedly persuaded by Berzelius to investigate ceria further.[39][40][41][42]

The element played a role in the Manhattan Project, where cerium compounds were investigated in the Berkeley site as materials for crucibles for uranium and plutonium casting.[43] For this reason, new methods for the preparation and casting of cerium were developed within the scope of the Ames daughter project (now the Ames Laboratory).[44] Production of extremely pure cerium in Ames commenced in mid-1944 and continued until August 1945.[44]

Occurrence and production

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Cerium is the most abundant of all the lanthanides and the 25th most abundant element, making up 68 ppm of the Earth's crust.[45] This value is the same of copper, and cerium is even more abundant than common metals such as lead (13 ppm) and tin (2.1 ppm). Thus, despite its position as one of the so-called rare-earth metals, cerium is actually not rare at all.[46] Cerium content in the soil varies between 2 and 150 ppm, with an average of 50 ppm; seawater contains 1.5 parts per trillion of cerium.[38] Cerium occurs in various minerals, but the most important commercial sources are the minerals of the monazite and bastnäsite groups, where it makes up about half of the lanthanide content. Monazite-(Ce) is the most common representative of the monazites, with "-Ce" being the Levinson suffix informing on the dominance of the particular REE element representative.[47][48][49] Also the cerium-dominant bastnäsite-(Ce) is the most important of the bastnäsites.[50][47] Cerium is the easiest lanthanide to extract from its minerals because it is the only one that can reach a stable +4 oxidation state in aqueous solution.[51] Because of the decreased solubility of cerium in the +4 oxidation state, cerium is sometimes depleted from rocks relative to the other rare-earth elements and is incorporated into zircon, since Ce4+ and Zr4+ have the same charge and similar ionic radii.[52] In extreme cases, cerium(IV) can form its own minerals separated from the other rare-earth elements, such as cerianite-(Ce)[53][49][47] and (Ce,Th)O2.[54]

Crystal structure of basntäsite-(Ce).
Crystal structure of bastnäsite-(Ce). Color code: carbon, C, blue-gray; fluorine, F, green; cerium, Ce, white; oxygen, O, red.

Bastnäsite, LnIIICO3F, is usually lacking in thorium and the heavy lanthanides beyond samarium and europium, and hence the extraction of cerium from it is quite direct. First, the bastnäsite is purified, using dilute hydrochloric acid to remove calcium carbonate impurities. The ore is then roasted in the air to oxidize it to the lanthanide oxides: while most of the lanthanides will be oxidized to the sesquioxides Ln2O3, cerium will be oxidized to the dioxide CeO2. This is insoluble in water and can be leached out with 0.5 M hydrochloric acid, leaving the other lanthanides behind.[51]

The procedure for monazite, (Ln,Th)PO4, which usually contains all the rare earths, as well as thorium, is more involved. Monazite, because of its magnetic properties, can be separated by repeated electromagnetic separation. After separation, it is treated with hot concentrated sulfuric acid to produce water-soluble sulfates of rare earths. The acidic filtrates are partially neutralized with sodium hydroxide to pH 3–4. Thorium precipitates out of solution as hydroxide and is removed. After that, the solution is treated with ammonium oxalate to convert rare earths to their insoluble oxalates. The oxalates are converted to oxides by annealing. The oxides are dissolved in nitric acid, but cerium oxide is insoluble in HNO3 and hence precipitates out.[20] Care must be taken when handling some of the residues as they contain 228Ra, the daughter of 232Th, which is a strong gamma emitter.[51]

Applications

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Carl Auer von Welsbach
Carl Auer von Welsbach, who discovered many applications of cerium

Cerium has two main applications, both of which use CeO2. The industrial application of ceria is for polishing, especially chemical-mechanical planarization (CMP). In its other main application, CeO2 is used to decolorize glass. It functions by converting green-tinted ferrous impurities to nearly colorless ferric oxides.[55] Ceria has also been used as a substitute for its radioactive congener thoria, for example in the manufacture of electrodes used in gas tungsten arc welding, where ceria as an alloying element improves arc stability and ease of starting while decreasing burn-off.[56]

Gas mantles and pyrophoric alloys

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The first use of cerium was in gas mantles, invented by Austrian chemist Carl Auer von Welsbach. In 1885, he had previously experimented with mixtures of magnesium, lanthanum, and yttrium oxides, but these gave green-tinted light and were unsuccessful.[57] Six years later, he discovered that pure thorium oxide produced a much better, though blue, light, and that mixing it with cerium dioxide resulted in a bright white light.[58] Cerium dioxide also acts as a catalyst for the combustion of thorium oxide.[citation needed]

This resulted in commercial success for von Welsbach and his invention, and created great demand for thorium. Its production resulted in a large amount of lanthanides being simultaneously extracted as by-products.[59] Applications were soon found for them, especially in the pyrophoric alloy known as "mischmetal" composed of 50% cerium, 25% lanthanum, and the remainder being the other lanthanides, that is used widely for lighter flints.[59] Usually iron is added to form the alloy ferrocerium, also invented by von Welsbach.[60] Due to the chemical similarities of the lanthanides, chemical separation is not usually required for their applications, such as the addition of mischmetal to steel as an inclusion modifier to improve mechanical properties, or as catalysts for the cracking of petroleum.[51] This property of cerium saved the life of writer Primo Levi at the Auschwitz concentration camp, when he found a supply of ferrocerium alloy and bartered it for food.[61]

Pigments and phosphors

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The photostability of pigments can be enhanced by the addition of cerium, as it provides pigments with lightfastness and prevents clear polymers from darkening in sunlight.[62] An example of a cerium compound used on its own as an inorganic pigment is the vivid red cerium(III) sulfide (cerium sulfide red), which stays chemically inert up to very high temperatures. The pigment is a safer alternative to lightfast but toxic cadmium selenide-based pigments.[38] The addition of cerium oxide to older cathode-ray tube television glass plates was beneficial, as it suppresses the darkening effect from the creation of F-center defects due to the continuous electron bombardment during operation. Cerium is also an essential component as a dopant for phosphors used in CRT TV screens, fluorescent lamps, and later white light-emitting diodes.[63][64] The most commonly used example is cerium(III)-doped yttrium aluminium garnet (Ce:YAG) which emits green to yellow-green light (550–530 nm) and also behaves as a scintillator.[65]

Other uses

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Cerium salts, such as the sulfides Ce2S3 and Ce3S4, were considered during the Manhattan Project as advanced refractory materials for the construction of crucibles which could withstand the high temperatures and strongly reducing conditions when casting plutonium metal.[43][44] Despite desirable properties, these sulfides were never widely adopted due to practical issues with their synthesis.[43] Cerium is used as alloying element in aluminium to create castable eutectic aluminium alloys with 6–16 wt.% Ce, to which other elements such as Mg, Ni, Fe and Mn can be added. These Al-Ce alloys have excellent high temperature strength and are suitable for automotive applications (e.g. in cylinder heads).[66] Other alloys of cerium include Pu-Ce and Pu-Ce-Co plutonium alloys, which have been used as nuclear fuel.[67]

Other automotive applications for the lower sesquioxide are as a catalytic converter for the oxidation of CO and NOx emissions in the exhaust gases from motor vehicles.[68][69]

Biological role and precautions

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Cerium
Hazards
GHS labelling:[70]
GHS02: Flammable
Danger
H228
P210
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformFlammability 0: Will not burn. E.g. waterInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
2
0
0

The early lanthanides have been found to be essential to some methanotrophic bacteria living in volcanic mudpots, such as Methylacidiphilum fumariolicum: lanthanum, cerium, praseodymium, and neodymium are about equally effective.[71][72] Cerium is otherwise not known to have biological role in any other organisms, but is not very toxic either; it does not accumulate in the food chain to any appreciable extent.[73][74][75] Because it often occurs together with calcium in phosphate minerals, and bones are primarily calcium phosphate, cerium can accumulate in bones in small amounts that are not considered dangerous.[76]

Cerium nitrate is an effective topical antimicrobial treatment for third-degree burns,[38][77] although large doses can lead to cerium poisoning and methemoglobinemia.[78] The early lanthanides act as essential cofactors for the methanol dehydrogenase of the methanotrophic bacterium Methylacidiphilum fumariolicum SolV, for which lanthanum, cerium, praseodymium, and neodymium alone are about equally effective.[79]

Like all rare-earth metals, cerium is of low to moderate toxicity.[80] A strong reducing agent, it ignites spontaneously in air at 65 to 80 °C. Fumes from cerium fires are toxic.[38] Cerium reacts with water to produce hydrogen gas, and thus cerium fires can only be effectively extinguished using class D dry powder extinguishing media.[81] Workers exposed to cerium have experienced itching, sensitivity to heat, and skin lesions. Cerium is not toxic when eaten, but animals injected with large doses of cerium have died due to cardiovascular collapse. Cerium is more dangerous to aquatic organisms because it damages cell membranes; it is not very soluble in water and can cause environmental contamination.[38]

Cerium oxide, the most prevalent cerium compound in industrial applications, is not regulated in the United States by the Occupational Safety and Health Administration (OSHA) as a hazardous substance.[82] In Russia, its occupational exposure limit is 5 mg/m3.[80] Elemental cerium has no established occupational or permissible exposure limits by the by the OSHA or American Conference of Governmental Industrial Hygienists, though it is classified as a flammable solid and regulated as such under the Globally Harmonized System of Classification and Labelling of Chemicals.[83] Toxicological reports on cerium compounds have noted their cytotoxicity[80] and contributions to pulmonary interstitial fibrosis in workers.[84]

References

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  1. ^ "Standard Atomic Weights: Cerium". CIAAW. 1995.
  2. ^ Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (2022-05-04). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN 1365-3075.
  3. ^ Ground levels and ionization energies for the neutral atoms, NIST
  4. ^ a b c d Arblaster, John W. (2018). Selected Values of the Crystallographic Properties of Elements. Materials Park, Ohio: ASM International. ISBN 978-1-62708-155-9.
  5. ^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 28. ISBN 978-0-08-037941-8.
  6. ^ Lide, D. R., ed. (2005). "Magnetic susceptibility of the elements and inorganic compounds". CRC Handbook of Chemistry and Physics (PDF) (86th ed.). Boca Raton (FL): CRC Press. ISBN 0-8493-0486-5.
  7. ^ Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.
  8. ^ Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.
  9. ^ a b c Lide, D. R., ed. (2005). CRC Handbook of Chemistry and Physics (86th ed.). Boca Raton, Florida: CRC Press. ISBN 0-8493-0486-5.
  10. ^ Greenwood & Earnshaw 1997, pp. 1232–5.
  11. ^ Jørgensen, Christian (1973). "The Loose Connection between Electron Configuration and the Chemical Behavior of the Heavy Elements (Transuranics)". Angewandte Chemie International Edition. 12 (1): 12–19. doi:10.1002/anie.197300121.
  12. ^ Holleman, Arnold Frederik; Wiberg, Egon (2001), Wiberg, Nils (ed.), Inorganic Chemistry, translated by Eagleson, Mary; Brewer, William, San Diego/Berlin: Academic Press/De Gruyter, pp. 1703–5, ISBN 0-12-352651-5
  13. ^ Wills, J. M.; Eriksson, Olle; Boring, A. M. (1991-10-14). "Theoretical studies of the high pressure phases in cerium". Physical Review Letters. 67 (16): 2215–2218. Bibcode:1991PhRvL..67.2215W. doi:10.1103/PhysRevLett.67.2215. ISSN 0031-9007. PMID 10044368.
  14. ^ Johansson, Börje; Luo, Wei; Li, Sa; Ahuja, Rajeev (17 September 2014). "Cerium; Crystal Structure and Position in The Periodic Table". Scientific Reports. 4: 6398. Bibcode:2014NatSR...4.6398J. doi:10.1038/srep06398. PMC 4165975. PMID 25227991.
  15. ^ a b c d Greenwood & Earnshaw 1997, pp. 1244–8.
  16. ^ Gray, Theodore (2010). The Elements. Black Dog & Leventhal Pub. ISBN 978-1-57912-895-1.
  17. ^ "Chemical reactions of Cerium". Webelements. Retrieved 9 July 2016.
  18. ^ a b c d Koskimaki, D. C.; Gschneidner, K. A.; Panousis, N. T. (1974). "Preparation of single phase β and α cerium samples for low temperature measurements". Journal of Crystal Growth. 22 (3): 225–229. Bibcode:1974JCrGr..22..225K. doi:10.1016/0022-0248(74)90098-0.
  19. ^ Stassis, C.; Gould, T.; McMasters, O.; Gschneidner, K.; Nicklow, R. (1979). "Lattice and spin dynamics of γ-Ce". Physical Review B. 19 (11): 5746–5753. Bibcode:1979PhRvB..19.5746S. doi:10.1103/PhysRevB.19.5746.
  20. ^ a b Patnaik, Pradyot (2003). Handbook of Inorganic Chemical Compounds. McGraw-Hill. pp. 199–200. ISBN 978-0-07-049439-8.
  21. ^ a b c d e Audi, G.; Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S. (2017). "The NUBASE2016 evaluation of nuclear properties" (PDF). Chinese Physics C. 41 (3): 030001. Bibcode:2017ChPhC..41c0001A. doi:10.1088/1674-1137/41/3/030001.
  22. ^ Belli, P.; Bernabei, R.; Danevich, F. A.; Incicchitti, A.; Tretyak, V. I. (2019). "Experimental searches for rare alpha and beta decays". European Physical Journal A. 55 (140): 4–6. arXiv:1908.11458. Bibcode:2019EPJA...55..140B. doi:10.1140/epja/i2019-12823-2. S2CID 201664098.
  23. ^ a b Cameron, A. G. W. (1973). "Abundance of the Elements in the Solar System" (PDF). Space Science Reviews. 15 (1): 121–146. Bibcode:1973SSRv...15..121C. doi:10.1007/BF00172440. S2CID 120201972.
  24. ^ Greenwood & Earnshaw 1997, pp. 1240–2.
  25. ^ a b Greenwood & Earnshaw 1997, pp. 1238–9.
  26. ^ Nair, Vijay; Deepthi, Ani (2007). "Cerium(IV) Ammonium Nitrate: A Versatile Single-Electron Oxidant". Chemical Reviews. 107 (5): 1862–1891. doi:10.1021/cr068408n. PMID 17432919.
  27. ^ a b Sridharan, Vellaisamy; Menéndez, J. Carlos (2010). "Cerium(IV) Ammonium Nitrate as a Catalyst in Organic Synthesis". Chemical Reviews. 110 (6): 3805–3849. doi:10.1021/cr100004p. PMID 20359233.
  28. ^ Gupta, C. K. & Krishnamurthy, Nagaiyar (2004). Extractive metallurgy of rare earths. CRC Press. p. 30. ISBN 978-0-415-33340-5.
  29. ^ Gschneidner K.A., ed. (2006). "Chapter 229: Applications of tetravalent cerium compounds". Handbook on the Physics and Chemistry of Rare Earths, Volume 36. The Netherlands: Elsevier. pp. 286–288. ISBN 978-0-444-52142-2.
  30. ^ Sroor, Farid M.A.; Edelmann, Frank T. (2012). "Lanthanides: Tetravalent Inorganic". Encyclopedia of Inorganic and Bioinorganic Chemistry. doi:10.1002/9781119951438.eibc2033. ISBN 978-1-119-95143-8.
  31. ^ McGill, Ian. "Rare Earth Elements". Ullmann's Encyclopedia of Industrial Chemistry. Vol. 31. Weinheim: Wiley-VCH. p. 190. doi:10.1002/14356007.a22_607. ISBN 978-3527306732.
  32. ^ B. P. Belousov (1959). "Периодически действующая реакция и ее механизм" [Periodically acting reaction and its mechanism]. Сборник рефератов по радиационной медицине (in Russian). 147: 145.
  33. ^ Greenwood & Earnshaw 1997, pp. 1248–9.
  34. ^ Schelter, Eric J. (20 March 2013). "Cerium under the lens". Nature Chemistry. 5 (4): 348. Bibcode:2013NatCh...5..348S. doi:10.1038/nchem.1602. PMID 23511425.
  35. ^ Mikhail N. Bochkarev (2004). "Molecular compounds of "new" divalent lanthanides". Coordination Chemistry Reviews. 248 (9–10): 835–851. doi:10.1016/j.ccr.2004.04.004.
  36. ^ M. Cristina Cassani; Yurii K. Gun'ko; Peter B. Hitchcock; Alexander G. Hulkes; Alexei V. Khvostov; Michael F. Lappert; Andrey V. Protchenko (2002). "Aspects of non-classical organolanthanide chemistry". Journal of Organometallic Chemistry. 647 (1–2): 71–83. doi:10.1016/s0022-328x(01)01484-x.
  37. ^ a b c "Visual Elements: Cerium". London: Royal Society of Chemistry. 1999–2012. Retrieved December 31, 2009.
  38. ^ a b c d e f g Emsley, John (2011). Nature's Building Blocks: An A-Z Guide to the Elements. Oxford University Press. pp. 120–125. ISBN 978-0-19-960563-7.
  39. ^ Weeks, Mary Elvira (1956). The discovery of the elements (6th ed.). Easton, PA: Journal of Chemical Education.
  40. ^ Weeks, Mary Elvira (1932). "The Discovery of the Elements: XI. Some Elements Isolated with the Aid of Potassium and Sodium: Zirconium, Titanium, Cerium and Thorium". The Journal of Chemical Education. 9 (7): 1231–1243. Bibcode:1932JChEd...9.1231W. doi:10.1021/ed009p1231.
  41. ^ Marshall, James L. Marshall; Marshall, Virginia R. Marshall (2015). "Rediscovery of the elements: The Rare Earths–The Beginnings" (PDF). The Hexagon: 41–45. Retrieved 30 December 2019.
  42. ^ Marshall, James L. Marshall; Marshall, Virginia R. Marshall (2015). "Rediscovery of the elements: The Rare Earths–The Confusing Years" (PDF). The Hexagon: 72–77. Retrieved 30 December 2019.
  43. ^ a b c Hirai, Shinji; Shimakage, Kazuyoshi; Saitou, Yasushi; Nishimura, Toshiyuki; Uemura, Yoichiro; Mitomo, Mamoru; Brewer, Leo (2005-01-21). "Synthesis and Sintering of Cerium(III) Sulfide Powders". Journal of the American Ceramic Society. 81 (1): 145–151. doi:10.1111/j.1151-2916.1998.tb02306.x.
  44. ^ a b c Hadden, Gavin, ed. (1946). "Chapter 11 - Ames Project". Manhattan District History. Vol. 4. Washington, D.C.: United States Army Corps of Engineers.
  45. ^ Emsley, John (2003). Nature's Building Blocks: An A-Z Guide to the Elements. Oxford University Press. ISBN 978-0-19-850340-8.
  46. ^ Greenwood & Earnshaw 1997, pp. 1294.
  47. ^ a b c Burke, Ernst A.J. (2008). "The use of suffixes in mineral names" (PDF). Elements. 4 (2): 96. Archived from the original (PDF) on 19 December 2019. Retrieved 7 December 2019.
  48. ^ "Monazite-(Ce): Mineral information, data and localities". www.mindat.org.
  49. ^ a b "CNMNC". nrmima.nrm.se. Archived from the original on 2019-08-10. Retrieved 2018-10-06.
  50. ^ "Bastnäsite-(Ce): Mineral information, data and localities". www.mindat.org.
  51. ^ a b c d Greenwood & Earnshaw 1997, pp. 1229–1232.
  52. ^ Thomas, J. B.; Bodnar, R. J.; Shimizu, N.; Chesner, C. A. (2003). "Melt inclusions in zircon". Reviews in Mineralogy and Geochemistry. 53 (1): 63–87. Bibcode:2003RvMG...53...63T. doi:10.2113/0530063.
  53. ^ "Cerianite-(Ce): Mineral information, data and localities". www.mindat.org.
  54. ^ Graham, A. R. (1955). "Cerianite CeO2: a new rare-earth oxide mineral". American Mineralogist. 40: 560–564.
  55. ^ Klaus Reinhardt; Herwig Winkler (2000). "Cerium Mischmetal, Cerium Alloys, and Cerium Compounds". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a06_139. ISBN 978-3527306732..
  56. ^ AWS D10.11M/D10.11 - An American National Standard - Guide for Root Pass Welding of Pipe Without Backing. American Welding Society. 2007.
  57. ^ Lewes, Vivian Byam (1911). "Lighting" . In Chisholm, Hugh (ed.). Encyclopædia Britannica. Vol. 16 (11th ed.). Cambridge University Press. p. 656.
  58. ^ Wickleder, Mathias S.; Fourest, Blandine; Dorhout, Peter K. (2006). "Thorium". In Morss, Lester R.; Edelstein, Norman M.; Fuger, Jean (eds.). The Chemistry of the Actinide and Transactinide Elements (PDF). Vol. 3 (3rd ed.). Dordrecht, the Netherlands: Springer. pp. 52–160. doi:10.1007/1-4020-3598-5_3. ISBN 978-1-4020-3555-5. Archived from the original (PDF) on 2016-03-07.
  59. ^ a b Greenwood & Earnshaw 1997, pp. 1228.
  60. ^ Klaus Reinhardt and Herwig Winkler in "Cerium Mischmetal, Cerium Alloys, and Cerium Compounds" in Ullmann's Encyclopedia of Industrial Chemistry 2000, Wiley-VCH, Weinheim. doi:10.1002/14356007.a06_139
  61. ^ Wilkinson, Tom (6 November 2009). "Book Of A Lifetime: The Periodic Table, By Primo Levi". The Independent. Retrieved 25 October 2016.
  62. ^ Gleń, Marta; Grzmil, Barbara; Sreńscek-Nazzal, Joanna; Kic, Bogumił (2011-04-01). "Effect of CeO2 and Sb2O3 on the phase transformation and optical properties of photostable titanium dioxide". Chemical Papers. 65 (2): 203–212. doi:10.2478/s11696-010-0103-x. ISSN 1336-9075. S2CID 94458692.
  63. ^ Cerium dioxide Archived 2013-03-02 at the Wayback Machine. nanopartikel.info (2011-02-02)
  64. ^ Trovarelli, Alessandro (2002). Catalysis by ceria and related materials. Imperial College Press. pp. 6–11. ISBN 978-1-86094-299-0.
  65. ^ Lu, Chung-Hsin; Hong, Hsin-Cheng; Jagannathan, R. (2002-01-01). "Sol–gel synthesis and photoluminescent properties of cerium-ion doped yttrium aluminium garnet powders". Journal of Materials Chemistry. 12 (8): 2525–2530. doi:10.1039/B200776M. ISSN 1364-5501.
  66. ^ Sims, Zachary (2016). "Cerium-Based, Intermetallic-Strengthened Aluminum Casting Alloy: High-Volume Co-product Development". JOM. 68 (7): 1940–1947. Bibcode:2016JOM....68g1940S. doi:10.1007/s11837-016-1943-9. OSTI 1346625. S2CID 138835874.
  67. ^ Leary, J. A.; Mullins, L. J. (1964-11-01). PREPARATION OF TERNARY PLUTONIUM ALLOYS FOR CORE TEST FACILITY PROGRAM (Report). Los Alamos National Lab. (LANL), Los Alamos, NM (United States). OSTI 4650650.
  68. ^ Bleiwas, D.I. (2013). Potential for Recovery of Cerium Contained in Automotive Catalytic Converters. Reston, Va.: U.S. Department of the Interior, U.S. Geological Survey.
  69. ^ "Argonne's deNOx Catalyst Begins Extensive Diesel Engine Exhaust Testing". Argonne National Laboratory. Archived from the original on 2015-09-07. Retrieved 2014-06-02.
  70. ^ "Cerium GF39030353". 2021-09-22. Retrieved 2021-12-22.
  71. ^ Pol, Arjan; Barends, Thomas R. M.; Dietl, Andreas; Khadem, Ahmad F.; Eygensteyn, Jelle; Jetten, Mike S. M.; Op Den Camp, Huub J. M. (2013). "Rare earth metals are essential for methanotrophic life in volcanic mudpots" (PDF). Environmental Microbiology. 16 (1): 255–64. doi:10.1111/1462-2920.12249. PMID 24034209.
  72. ^ Kang, L.; Shen, Z.; Jin, C. (April 2000). "Neodymium cations Nd3+ were transported to the interior of Euglena gracilis 277". Chin. Sci. Bull. 45 (7): 585–592. Bibcode:2000ChSBu..45..585K. doi:10.1007/BF02886032.
  73. ^ Hawthorne, Joseph; De la Torre Roche, Roberto; Xing, Baoshan; Newman, Lee A.; Ma, Xingmao; Majumdar, Sanghamitra; Gardea-Torresdey, Jorge; White, Jason C. (2014-11-18). "Particle-Size Dependent Accumulation and Trophic Transfer of Cerium Oxide through a Terrestrial Food Chain". Environmental Science & Technology. 48 (22): 13102–13109. Bibcode:2014EnST...4813102H. doi:10.1021/es503792f. ISSN 0013-936X. PMID 25340623.
  74. ^ Majumdar, Sanghamitra; Trujillo-Reyes, Jesica; Hernandez-Viezcas, Jose A.; White, Jason C.; Peralta-Videa, Jose R.; Gardea-Torresdey, Jorge L. (2016-07-05). "Cerium Biomagnification in a Terrestrial Food Chain: Influence of Particle Size and Growth Stage". Environmental Science & Technology. 50 (13): 6782–6792. Bibcode:2016EnST...50.6782M. doi:10.1021/acs.est.5b04784. ISSN 0013-936X. PMID 26690677.
  75. ^ Gupta, Govind Sharan; Shanker, Rishi; Dhawan, Alok; Kumar, Ashutosh (2017), Ranjan, Shivendu; Dasgupta, Nandita; Lichtfouse, Eric (eds.), "Impact of Nanomaterials on the Aquatic Food Chain", Nanoscience in Food and Agriculture 5, Sustainable Agriculture Reviews, vol. 26, Cham: Springer International Publishing, pp. 309–333, doi:10.1007/978-3-319-58496-6_11, ISBN 978-3-319-58496-6, retrieved 2023-08-12
  76. ^ Jakupec, M. A.; Unfried, P.; Keppler, B. K. (2005). "Pharmacological properties of cerium compunds". Reviews of Physiology, Biochemistry and Pharmacology. 153. Berlin, Heidelberg: Springer Berlin Heidelberg: 101–111. doi:10.1007/s10254-004-0024-6. ISBN 978-3-540-24012-9. PMID 15674649. Retrieved 2023-08-05.
  77. ^ Dai, Tianhong; Huang, Ying-Ying; Sharma, Sulbha K.; Hashmi, Javad T.; Kurup, Divya B.; Hamblin, Michael R. (2010). "Topical antimicrobials for burn wound infections". Recent Pat Anti-Infect Drug Discov. 5 (2): 124–151. doi:10.2174/157489110791233522. PMC 2935806. PMID 20429870.
  78. ^ Attof, Rachid; Magnin, Christophe; Bertin-Maghit, Marc; Olivier, Laure; Tissot, Sylvie; Petit, Paul (2007). "Methemoglobinemia by cerium nitrate poisoning". Burns. 32 (8): 1060–1061. doi:10.1016/j.burns.2006.04.005. PMID 17027160.
  79. ^ Pol, Arjan; Barends, Thomas R.M.; Dietl, Andreas; Khadem, Ahmad F.; Eygensteyn, Jelle; Jetten, Mike S.M.; Op Den Camp, Huub J.M. (2013). "Rare earth metals are essential for methanotrophic life in volcanic mudpots" (PDF). Environmental Microbiology. 16 (1): 255–264. doi:10.1111/1462-2920.12249. PMID 24034209.
  80. ^ a b c Rim, Kyung Taek; Koo, Kwon Ho; Park, Jung Sun (March 2013). "Toxicological Evaluations of Rare Earths and Their Health Impacts to Workers: A Literature Review". Safety and Health at Work. 4 (1): 12–26. doi:10.5491/SHAW.2013.4.1.12. PMC 3601293. PMID 23516020.
  81. ^ Spellman, Frank R. (2022-12-30). The Science of Rare Earth Elements: Concepts and Applications. CRC Press. pp. 104–105. ISBN 978-1-000-82129-1.
  82. ^ "Cerium(IV) oxide, REacton Safety Data Sheet". Fisher Scientific. March 27, 2024. Retrieved August 27, 2024.
  83. ^ "Cerium Safety Data Sheet" (PDF). Ames Laboratory, U. S. Department of Energy. January 26, 2016. Retrieved August 27, 2024.
  84. ^ Environmental Protection Agency (September 2009). Toxicological Review of Cerium Oxide and Cerium Compounds (PDF) (Report). Washington, D.C.

Bibliography

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