Cerium
Atomic Number: 58
Symbol: Ce
Atomic Weight: 140.115
Element Classification: Rare Earth Element (Lanthanide Series)
Discovered By: W. von Hisinger, J. Berzelius, M. Klaproth
Discovery Date: 1803 (Sweden/Germany)
Name Origin: Named after the asteroid Ceres, discovered two years before the element.
Density (g/cc) near r.t.: 6.757
Melting Point (°K): 1072
Boiling Point (°K): 3699
Appearance: Malleable, ductile, iron-gray metal
Atomic Radius (pm): 181
Atomic Volume (cc/mol): 21.0
Covalent Radius (pm): 165
Ionic Radius: 92 (+4e) 103.4 (+3e)
Specific Heat (@20°C J/g mol): 0.205
Fusion Heat (kJ/mol): 5.2
Evaporation Heat (kJ/mol): 398
Pauling Negativity Number: 1.12
First Ionizing Energy (kJ/mol): 540.1
Oxidation States: 4, 3
Electronic Configuration: [Xe] 4f1 5d1 6s2
Lattice Structure: Face-Centered Cubic (FCC)
Lattice Constant (Å): 5.160
Electrons per Shell: 2, 8, 18, 19, 9, 2
Phase: Solid
Liquid Density at m.p.: 6.55 g·cm−3
Heat of Fusion: 5.46 kJ·mol−1
Heat of Vaporization: 398 kJ·mol−1
Heat Capacity (25 °C): 26.94 J·mol−1·K−1
Electronegativity: 1.12 (Pauling scale)
Atomic Radius: 185 pm
Electrical Resistivity (r.t.): (β, poly) 828 nΩ·m
Thermal Conductivity (300 K): 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
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: 270 MPa
Brinell Hardness: 412 MPa
CAS Registry Number: 7440-45-1
Sources: Los Alamos National Laboratory (2001), Crescent Chemical Company (2001), Lange's Handbook of Chemistry (1952)
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