Hafnium (Hf) — Atomic Data, Electron Shells & Reactions

Atomic Number (Z) 72 IUPAC Symbol Hf Standard Atomic Weight 178.49 g/mol Period / Group / Block 6 / 4 / d-block Condensed Electron Config [Xe] 4f14 5d2 6s2 Full Subshell Config 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d2 6s2 Principal Shell Occupancy [2, 8, 18, 32, 10, 2] Pauling Electronegativity 1.3 First Ionization Energy 659 kJ/mol Covalent Radius 175 pm Melting Point 2506 K (2232.85 °C) Boiling Point 4876 K (4602.85 °C) Density 13.31 g/cm³ Oxidation States +4