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Cerium is a chemical element wi seembol Ce an atomic nummer 58. It is a saft, silvery, ductile metal which easily oxidizes in air. Cerium wis named efter the dwarf planet Ceres (itsel named for the Roman goddess o agricultur). Cerium is the maist abundant o the rare yird elements, makin up aboot 0.0046% o the Yird's crust bi wicht. It is foond in a feck o minerals, the maist important bein monazite an bastnasite. Thare a wheen o ommercial applications o cerium. Thay include catalysts, additives fur tae fuel tae reduce emissions an tae gless an enamels tae chynge thair colour. Cerium oxide is an important component o gless polishin pouders an phosphors uised in screens an fluorescent lamps. It is uised in the "flint" (actually ferrocerium) o lichters.

Cerium,  58Ce
Cerium2.jpg
General properties
Appearancesillery white
Staundart atomic wecht (Ar, staundart)140.116(1)[1]
Cerium in the periodic cairt
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 Airn Cobalt Nickel Capper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Siller (element) 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 Gowd Mercur (element) Thallium Leid (element) 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 Ununtrium Flerovium Ununpentium Livermorium Ununseptium Ununoctium
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Ce

Th
lanthanumceriumpraseodymium
Atomic nummer (Z)58
Groupgroup n/a
Periodperiod 6
Element category  lanthanide
Blockf-block
Electron confeeguration[Xe] 4f1 5d1 6s2[2]
Electrons per shell
2, 8, 18, 19, 9, 2
Pheesical properties
Phase (at STP)solit
Meltin pynt1068 K ​(795 °C, ​1463 °F)
Bylin pynt3716 K ​(3443 °C, ​6229 °F)
Density (near r.t.)6.770 g/cm3
when liquid (at m.p.)6.55 g/cm3
Heat o fusion5.46 kJ/mol
Heat o vapourisation398 kJ/mol
Molar heat capacity26.94 J/(mol·K)
Vapour pressur
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 1992 2194 2442 2754 3159 3705
Atomic properties
Oxidation states4, 3, 2, 1
(mildly basic oxide)
ElectronegativityPauling scale: 1.12
Atomic radiusempirical: 181.8 pm
Covalent radius204±9 pm
Coloyr lines in a spectral range
Spectral lines o Cerium
Miscellanea
Creestal structurface-centred cubic (fcc)
Face-centered cubic creestal structur for cerium
Speed o soond thin rod2100 m/s (at 20 °C)
Thermal expansion(r.t.) (γ, poly) 6.3 µm/(m·K)
Thermal conductivity11.3 W/(m·K)
Electrical resistivity(r.t.) (β, poly) 828 n Ω·m
Magnetic orderinparamagnetic[3]
Young's modulus(γ form) 33.6 GPa
Shear modulus(γ form) 13.5 GPa
Bouk modulus(γ form) 21.5 GPa
Poisson ratio(γ form) 0.24
Mohs haurdness2.5
Vickers haurdness270 MPa
Brinell haurdness412 MPa
CAS Nummer7440-45-1
History
Naminefter dwarf planet Ceres, itsel named efter Roman deity o agricultur Ceres
DiskiveryMartin Heinrich Klaproth, Jöns Jakob Berzelius, Wilhelm Hisinger (1803)
First isolationCarl Gustaf Mosander (1839)
Main isotopes o cerium
Iso­tope Abun­dance Hauf-life (t1/2) Decay mode Pro­duct
134Ce syn 3.16 d ε 134La
136Ce 0.185% >3.8×1016 y (β+β+) 136Ba
138Ce 0.251% >1.5×1014 y (β+β+) 138Ba
139Ce syn 137.640 d ε 139La
140Ce 88.450% - (SF)
141Ce syn 32.501 d β 141Pr
142Ce 11.114% >5×1016 y (ββ) 142Nd
(α) 138Ba
144Ce syn 284.893 d β 144Pr
Decay modes in parentheses is predict, but hisna yet been observed
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