Symbol: Hf
Atomic Number: 72
Atomic Weight: 178.49
Element Classification: Transition Metal
Discovered By: Dirk Coster, Georg von Hevesy
Discovery Date: 1923 (Denmark)
Name Origin: Hafnia, the Latin name of Copenhagen.
Density (g/cc): 13.31
Melting Point (K): 2503
Boiling Point (K): 5470
Appearance: Silvery, ductile metal
Atomic Radius (pm): 167
Atomic Volume (cc/mol): 13.6
Covalent Radius (pm): 144
Ionic Radius: 78 (+4e)
Specific Heat (@20°C J/g mol): 0.146
Fusion Heat (kJ/mol): (25.1)
Evaporation Heat (kJ/mol): 575
Thermal Conductivity (@25°C W/m K):
Debye Temperature (K): n/a
Pauling Negativity Number: 1.3
First Ionizing Energy (kJ/mol): 575.2
Oxidation States: 4
Electronic Configuration: [Xe] 4f¹⁴ 5d² 6s²
Lattice Structure: Hexagonal (HEX)
Lattice Constant (Å): 3.200
Lattice C/A Ratio: 1.582