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About Cerium

Cerium Bohr

Cerium was discovered in 1803 by Jons Jacob Berzelius and named after the then recently-discovered dwarf planet Ceres. Like most of its fellow rare earth elements--of which it is the most abundant--cerium was initially identified in the form of its oxide, referred to as ceria, and was not obtained as a pure metal until decades after its initial discovery. Nonetheless, both salts and metallic mixtures containing cerium quickly found uses in industry. Cerium salts were found to have anti-emetic properties, and soon found their way into cough tinctures and antibacterial treatments. Around the same time, Carl Auer von Welsbach, an Austrian scientist with a knack for commercializing his discoveries, successfully developed two products requiring the use of cerium: gas mantles and lighter flints. Auer’s gas mantles were simple devices--cotton fabric soaked in mixtures of salts--but the glow they emitted when heated allowed for brighter, whiter light to be shed by gas lamps. Cerium found a third use in the early days of artificial lighting in carbon-arc lamps, which were particularly valued in film studios for their extreme brightness, which allowed them to mimic the look of natural sunlight.

With the exception of cerium nitrate, which is still available as an antiseptic and anti-inflammatory topical treatment for burns, cerium compounds find little use in modern medicine, but the use of cerium in lighting applications has continued and expanded: cerium containing lantern mantles and cerium alloy lighter flints are still in production, but today cerium-containing phosphors are also essential to the production of display screens and fluorescent lamps.

Cerium’s optical properties make it an important component of nontoxic alternatives to cadmium-based pigments and an important additive in the manufacture of glass, where it is used to provide golden coloring and allows for the selective blocking of UV light. Cerium also imparts valuable properties when added in small quantities to various alloys: it makes aluminum more resistant to corrosion, magnesium more resistant to heat, and helps reduce the sulfur and oxygen content of steel. The largest use of cerium by volume is as the polishing agent cerium (IV) oxide, which is used on precision optical components and to polish silicon wafers used in microchips. Cerium oxides are also useful as catalysts, and are used for that purpose in motor vehicle catalytic converters, petroleum refining, and solid oxide fuel cells.

Like other rare earth elements, cerium is never found in its pure form in nature. It can be obtained only from rare earth containing minerals such as xenotime, monazite, and bastnasite, or from ion-adsorption clays.

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Cerium is one of the products manufactured and distributed under the tradename AE Rare Earths. Its numerous commercial applications include uses in metallurgy, glass making and glass polishing, ceramics, catalysis, solid oxide fuel cells, and phosphors. In steel manufacturing it is used to remove free oxygen and sulfur by forming stable oxysulfides and by tying up undesirable trace elements, such as lead and antimony. It is considered to be the most efficient glass polishing agent for High Purity (99.999%) Cerium Oxide (CeO2) Powderprecision optical polishing. It is also used to de-colorize glass by keeping iron in its ferrous state. The ability of cerium-dopedHigh Purity (99.999%) Cerium (Ce) Sputtering Target glass to block out ultra violet light is utilized in the manufacturing of medical glassware and aerospace windows. It is also used to prevent polymers from darkening in sunlight and to suppress discoloration of television glass. Cerium is available as metal and compounds with purities from 99% to 99.999% (ACS grade to ultra-high purity). Elemental or metallic forms include pellets, rod, wire and granules for evaporation source material purposes. Cerium oxides are available in powder and dense pellet form for such uses as optical coating and thin film applications. Oxides tend to be insoluble. Cerium fluorides are another insoluble form for uses in which oxygen is undesirable such as metallurgy, chemical and physical vapor deposition and in some optical coatings. Cerium is also available in soluble forms including chlorides, nitrates and acetates. These compounds can be manufactured as solutions at specified stoichiometries.

Cerium Properties

Cerium (Ce) atomic and molecular weight, atomic number and elemental symbolCerium is a Block F, Group 3, Period 6 element. The number of electrons in each of cerium's shells is 2, 8, 18, 19, 9, 2 and its electron configuration is [Xe] 4f1 5d1 6s2. The cerium atom has a radius of and its Van der Waals radius is In its elemental form, CAS 7440-45-1, cerium has a silvery white appearance. Cerium is the most abundant of the rare earth metals. Cerium Bohr ModelIt is characterized chemically by having two valence states, the +3 cerous and +4 ceric states. Elemental CeriumThe ceric state is the only non-trivalent rare earth ion stable in aqueous solutions. It is, therefore, strongly acidic and moderately toxic. It is also a strong oxidizer. The cerous state closely resembles the other trivalent rare earths. Cerium is found in the minerals allanite, bastnasite, hydroxylbastnasite, monazite, rhabdophane, synchysite and zircon. Cerium was discovered by Jöns Jakob Berzeliusin 1803. It was first isolated by Carl Gustaf Mosander in 1839. The element was named after the asteroid Ceres.

Symbol: Ce
Atomic Number: 58
Atomic Weight: 140.116
Element Category: Lanthanide
Group, Period, Block: n/a, 6, f
Color: silvery white/ gray
Other Names: Cerio
Melting Point: 799 °C, 1470.2 °F, 1072.15 K
Boiling Point: 3443 °C, 6229.4 °F, 3716.15 K
Density: 6711  kg·m3
Liquid Density @ Melting Point: 6.55 g·cm3
Density @ 20°C: 6.78 g/cm3
Density of Solid: 6689 kg·m3
Specific Heat: 0.049 Cal/g/K @ 25°C
Superconductivity Temperature: 0.022 [or -273.128 °C (-459.63 °F)] (under pressure) K
Triple Point: N/A
Critical Point: N/A
Heat of Fusion (kJ·mol-1): 8.87
Heat of Vaporization (kJ·mol-1): 398
Heat of Atomization (kJ·mol-1): 423.4
Thermal Conductivity: 0.113/cm/K @ 298.2 K
Thermal Expansion: (r.t.) 6.3 µm/(m·K)
Electrical Resistivity: ( 25 °C) 75.0 µΩ·m
Tensile Strength: N/A
Molar Heat Capacity: 26.94 J·mol-1·K-1
Young's Modulus: 33.6 GPa
Shear Modulus: 13.5 GPa
Bulk Modulus: 21.5 GPa
Poisson Ratio: 0.24
Mohs Hardness: 2.5
Vickers Hardness: 270 MPa
Brinell Hardness: 412 MPa
Speed of Sound: (20 °C) 2100 m·s-1
Pauling Electronegativity: 1.12
Sanderson Electronegativity: N/A
Allred Rochow Electronegativity: 1.08
Mulliken-Jaffe Electronegativity: N/A
Allen Electronegativity: N/A
Pauling Electropositivity: 2.88
Reflectivity (%): N/A
Refractive Index: N/A
Electrons: 58
Protons: 58
Neutrons: 82
Electron Configuration: [Xe] 4f1 5d1 6s2
Atomic Radius: 181.8 pm
Atomic Radius, non-bonded (Å): 2.42
Covalent Radius: 204±9 pm
Covalent Radius (Å): 1.84
Van der Waals Radius: 235 pm
Oxidation States: 4, 3, 2, 1 (mildly basic oxide)
Phase: Solid
Crystal Structure: Cubic
Magnetic Ordering: paramagnetic
Electron Affinity (kJ·mol-1) 62.715
1st Ionization Energy: 534.4 kJ·mol-1
2nd Ionization Energy: 1050 kJ·mol-1
3rd Ionization Energy: 1949 kJ·mol-1
CAS Number: 7440-45-1
EC Number: 231-154-9
MDL Number: MFCD00010924
Beilstein Number: N/A
SMILES Identifier: [Ce]
InChI Identifier: InChI=1S/Ce
PubChem CID: 23974
ChemSpider ID: 22411
Earth - Total: 1010 ppb 
Mercury - Total: 780 ppb
Venus - Total: 1060 ppb
Earth - Seawater (Oceans), ppb by weight: 0.0012
Earth - Seawater (Oceans), ppb by atoms: 0.000053
Earth -  Crust (Crustal Rocks), ppb by weight: 60000
Earth -  Crust (Crustal Rocks), ppb by atoms: 8900
Sun - Total, ppb by weight: 4
Sun - Total, ppb by atoms: 0.03
Stream, ppb by weight: 0.06
Stream, ppb by atoms: 0.0004
Meterorite (Carbonaceous), ppb by weight: 760
Meterorite (Carbonaceous), ppb by atoms: 110
Typical Human Body, ppb by weight: N/A
Typical Human Body, ppb by atom: N/A
Universe, ppb by weight: 10
Universe, ppb by atom: 0.09
Discovered By: Martin Heinrich Klaproth, Jöns Jakob Berzelius, Wilhelm Hisinger
Discovery Date: 1803
First Isolation: N/A

Health, Safety & Transportation Information for Cerium

Cerium is moderately toxic. Safety data for Cerium and its compounds can vary widely depending on the form. For potential hazard information, toxicity, and road, sea and air transportation limitations, such as DOT Hazard Class, DOT Number, EU Number, NFPA Health rating and RTECS Class, please see the specific material or compound referenced in the Products tab. The below information applies to elemental (metallic) Cerium.

Safety Data
Material Safety Data Sheet MSDS
Signal Word Danger
Hazard Statements H228-H302-H312-H315-H319-H332-H335
Hazard Codes F, Xn
Risk Codes 11-20/21/22-36/37/38
Safety Precautions 16-26-36/37/39
RTECS Number N/A
Transport Information UN 1333 4.1/PG 2
WGK Germany 3
Globally Harmonized System of
Classification and Labelling (GHS)
Exclamation Mark-Acute Toxicity Flame-Flammables

Cerium Isotopes

Naturally occurring cerium (Ce) has four stable isotopes: 136Ce, 138Ce, 140Ce, and 142Ce.

Nuclide Isotopic Mass Half-Life Mode of Decay Nuclear Spin Magnetic Moment Binding Energy (MeV) Natural Abundance
(% by atom)
119Ce 118.95276(64)# 200# ms ß+ to 119La 5/2+# N/A 942.87 -
120Ce 119.94664(75)# 250# ms ß+ to 120La 0+ N/A 960.26 -
121Ce 120.94342(54)# 1.1(1) s ß+ to 121La (5/2)(+#) N/A 968.34 -
122Ce 121.93791(43)# 2# s ß+ to 122La; ß+ + p to 121Ba 0+ N/A 985.74 -
123Ce 122.93540(32)# 3.8(2) s ß+ to 123La; ß+ + p to 122Ba (5/2)(+#) N/A 993.82 -
124Ce 123.93041(32)# 9.1(12) s ß+ to 124La 0+ N/A 1001.89 -
125Ce 124.92844(21)# 9.3(3) s ß+ to 125La; ß+ + p to 124Ba (7/2-) N/A 1019.29 -
126Ce 125.92397(3) 51.0(3) s ß+ to 126La 0+ N/A 1027.37 -
127Ce 126.92273(6) 29(2) s ß+ to 127La 5/2+# N/A 1035.45 -
128Ce 127.91891(3) 3.93(2) min ß+ to 128La 0+ N/A 1052.84 -
129Ce 128.91810(3) 3.5(3) min ß+ to 129La (5/2+) N/A 1060.92 -
130Ce 129.91474(3) 22.9(5) min ß+ to 130La 0+ N/A 1069 -
131Ce 130.91442(4) 10.2(3) min ß+ to 131La (7/2+) N/A 1077.08 -
132Ce 131.911460(22) 3.51(11) h ß+ to 132La 0+ N/A 1085.16 -
133Ce 132.911515(18) 97(4) min ß+ to 133La 1/2+ N/A 1093.24 -
134Ce 133.908925(22) 3.16(4) d EC to 134La 0+ N/A 1110.63 -
135Ce 134.909151(12) 17.7(3) h EC to 135La 1/2(+) N/A 1118.71 -
136Ce 135.907172(14) Observationally Stable - 0+ N/A 1126.79 0.185
137Ce 136.907806(14) 9.0(3) h EC to 137La 3/2+ N/A 1134.87 -
138Ce 137.905991(11) Observationally Stable - 0+ N/A 1142.95 0.251
139Ce 138.906653(8) 137.641(20) d EC to 139La 3/2+ 0.9 1151.02 -
140Ce 139.9054387(26) STABLE - 0+ N/A 1159.1 88.45
141Ce 140.9082763(26) 32.508(13) d ß- to 139La 7/2- 1.1 1167.18 -
142Ce 141.909244(3) Observationally Stable - 0+ N/A 1175.26 11.114
143Ce 142.912386(3) 33.039(6) h ß- to 143La 3/2- N/A 1174.02 -
144Ce 143.913647(4) 284.91(5) d ß- to 144La 0+ N/A 1182.1 -
145Ce 144.91723(4) 3.01(6) min ß- to 145La (3/2-) N/A 1190.18 -
146Ce 145.91876(7) 13.52(13) min ß- to 146La 0+ N/A 1198.26 -
147Ce 146.92267(3) 56.4(10) s ß- to 147La (5/2-) N/A 1197.02 -
148Ce 147.92443(3) 56(1) s ß- to 148La 0+ N/A 1205.1 -
149Ce 148.9284(1) 5.3(2) s ß- to 149La (3/2-)# N/A 1213.18 -
150Ce 149.93041(5) 4.0(6) s ß- to 150La 0+ N/A 1211.94 -
151Ce 150.93398(11) 1.02(6) s ß- to 151La 3/2-# N/A 1220.02 -
152Ce 151.93654(21)# 1.4(2) s ß- to 152La 0+ N/A 1228.1 -
153Ce 152.94058(43)# 500# ms [>300 ns] ß- to 153La 3/2-# N/A 1226.86 -
154Ce 153.94342(54)# 300# ms [>300 ns] ß- to 154La 0+ N/A 1234.94 -
155Ce 154.94804(64)# 200# ms [>300 ns] ß- to 155La 5/2-# N/A 1243.02 -
156Ce 155.95126(64)# 150# ms ß- to 156La 0+ N/A 1241.78 -
157Ce 156.95634(75)# 50# ms ß- to 157La 7/2+# N/A 1249.86 -