Template:Infobox cerium

Cerium,  ₅₈Ce

General properties
Name, symbol	cerium, Ce
Appearance	silvery white
Pronunciation	/ˈsɪəriəm/
Cerium in the periodic table
– ↑ Ce ↓ Th lanthanum ← cerium → praseodymium
Atomic number (Z)	58
Group, block	group n/a, f-block
Period	period 6
Element category	lanthanide
Standard atomic weight (±) (Ar)	140.116(1)
Electron configuration	[Xe] 4f1 5d1 6s2
per shell	2, 8, 18, 19, 9, 2
Physical properties
Phase	solid
Melting point	1068 K ​(795 °C, ​1463 °F)
Boiling point	3716 K ​(3443 °C, ​6229 °F)
Density near r.t.	6.770 g/cm3
when liquid, at m.p.	6.55 g/cm3
Heat of fusion	5.46 kJ/mol
Heat of vaporization	398 kJ/mol
Molar heat capacity	26.94 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 states	4, 3, 2, 1 ​(a mildly basic oxide)
Electronegativity	Pauling scale: 1.12
Ionization energies	1st: 534.4 kJ/mol 2nd: 1050 kJ/mol 3rd: 1949 kJ/mol (more)
Atomic radius	empirical: 181.8 pm
Covalent radius	204±9 pm
Miscellanea
Crystal structure	​double hexagonal close-packed (dhcp) β-Ce
Crystal structure	​face-centered cubic (fcc) γ-Ce
Speed of sound thin rod	2100 m/s (at 20 °C)
Thermal expansion	γ, poly: 6.3 µm/(m·K) (at r.t.)
Thermal conductivity	11.3 W/(m·K)
Electrical resistivity	β, poly: 828 nΩ·m (at r.t.)
Magnetic ordering	paramagnetic
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 hardness	2.5
Vickers hardness	210–470 MPa
Brinell hardness	186–412 MPa
CAS Number	7440-45-1
History
Naming	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)
Most stable isotopes of cerium
iso NA half-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 (β−β−) 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

References

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