Cerium Facts - Ce or Atomic Number 58

Cerium (Ce) is atomic number 58 on the periodic table. Like other lanthanides or rare earth elements, cerium is a soft, silver-colored metal. Its the most abundant of the rare earth elements. Cerium Basic Facts Element Name: 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. Cerium Physical Data 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 (Ã…): 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.): (ÃŽ ², poly) 828 nÃŽ ©Ã‚ ·m Thermal Conductivity (300 K): 11.3 W ·m−1 ·K−1 Thermal Expansion (r.t.): (ÃŽ ³, poly) 6.3  µm/(m ·K) Speed of Sound (thin rod) (20  °C): 2100 m/s Youngs Modulus (ÃŽ ³ form): 33.6 GPa Shear Modulus (ÃŽ ³ form): 13.5 GPa Bulk Modulus (ÃŽ ³ form): 21.5 GPa Poisson Ratio (ÃŽ ³ 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), Langes Handbook of Chemistry (1952) Return to the Periodic Table