Cerium

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Cerium
58Ce
-

Ce

Th
lanthanumceriumpraseodymium
Appearance
sillery white
General properties
Name, seembol, nummer cerium, Ce, 58
Pronunciation /ˈsɪəriəm/
Element category lanthanide
Group, period, block n/a, 6, f
Staundart atomic wicht 140.116
Electron confeeguration [Xe] 4f1 5d1 6s2[1]
2, 8, 18, 19, 9, 2
Electron shells of cerium (2, 8, 18, 19, 9, 2)
History
Namin after dwarf planet Ceres, itself named after Roman deity of agriculture Ceres
Discovery Martin Heinrich Klaproth, Jöns Jakob Berzelius, Wilhelm Hisinger (1803)
First isolation Carl Gustaf Mosander (1839)
Physical properties
Phase solid
Density (near r.t.) 6.770 g·cm−3
Liquid density at m.p. 6.55 g·cm−3
Meltin pynt 1068 K, 795 °C, 1463 °F
Boilin pynt 3716 K, 3443 °C, 6229 °F
Heat o fusion 5.46 kJ·mol−1
Heat o vaporization 398 kJ·mol−1
Molar heat capacity 26.94 J·mol−1·K−1
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 states 4, 3, 2, 1
(mildly basic oxide)
Electronegativity 1.12 (Pauling scale)
Ionization energies 1st: 534.4 kJ·mol−1
2nd: 1050 kJ·mol−1
3rd: 1949 kJ·mol−1
Atomic radius 181.8 pm
Covalent radius 204±9 pm
Miscellanea
Crystal structure face-centered cubic
Cerium has a face-centered cubic crystal structure
Magnetic orderin paramagnetic[2]
Electrical resistivity (r.t.) (β, poly) 828 nΩ·m
Thermal conductivity 11.3 W·m−1·K−1
Thermal expansion (r.t.) (γ, poly) 6.3 µm/(m·K)
Speed of sound (thin rod) (20 °C) 2100 m·s−1
Young's modulus (γ form) 33.6 GPa
Shear modulus (γ form) 13.5 GPa
Bulk modulus (γ form) 21.5 GPa
Poisson ratio (γ form) 0.24
Mohs hairdness 2.5
Vickers hairdness 270 MPa
Brinell hairdness 412 MPa
CAS registry nummer 7440-45-1
Most stable isotopes
Main article: Isotopes o cerium
iso NA hauf-life DM DE (MeV) DP
134Ce syn 3.16 d ε 0.500 134La
136Ce 0.185% >3.8×1016 y (β+β+) 2.419 136Ba
138Ce 0.251% >1.5×1014 y (β+β+) 0.694 138Ba
139Ce syn 137.640 d ε 0.278 139La
140Ce 88.450% - (SF) <43.633
141Ce syn 32.501 d β 0.581 141Pr
142Ce 11.114% >5×1016 y (ββ) 1.417 142Nd
(α) 1.298 138Ba
144Ce syn 284.893 d β 0.319 144Pr
Decay modes in parentheses are predicted, but have not yet been observed
· r

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 (itself 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 nummer o minerals, the maist important bein monazite an bastnasite. Commercial applications o cerium are numerous. Thay include catalysts, additives tae fuel tae reduce emissions an tae glass an enamels tae chynge thair colour. Cerium oxide is an important component o glass polishin powders an phosphors uised in screens an fluorescent lamps. It is an aa uised in the "flint" (actually ferrocerium) o lichters.

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