Symbol: Os
Atomic Number: 76
Atomic Weight: 190.23
Element Classification: Transition Metal
Discovered By: Smithson Tenant
Discovery Date: 1804 (England)
Name Origin: Greek: osme (odor).
Density (g/cc): 22.57
Melting Point (K): 3327
Boiling Point (K): 5300
Appearance: Blue-white, lustrous, hard metal
Atomic Radius (pm): 135
Atomic Volume (cc/mol): 8.43
Covalent Radius (pm): 126
Ionic Radius: 69 (+6e) 88 (+4e)
Specific Heat (@20°C J/g mol): 0.131
Fusion Heat (kJ/mol): 31.7
Evaporation Heat (kJ/mol): 738
Thermal Conductivity (@25°C W/m K):
Debye Temperature (K): n/a
Pauling Negativity Number: 2.2
First Ionizing Energy (kJ/mol): 819.8
Oxidation States: 8, 6, 4, 3, 2, 0, -2
Electronic Configuration: [Xe] 4f¹⁴ 5d⁶ 6s²
Lattice Structure: Hexagonal (HEX)
Lattice Constant (Å): 2.740
Lattice C/A Ratio: 1.579