Hafnium (Hf)

Hafnium is a chemical element with symbol Hf and atomic number 72. A lustrous, silvery gray, tetravalent transition metal, hafnium chemically resembles zirconium and is found in many zirconium minerals.

Atomic Number

72

Atomic Mass

178.49 u

Category

transition metal

Phase

solid

Density

13.31 g/cm³

Electron Shells

2, 8, 18, 32, 10, 2

Atomic Structure

Protons: 72 • Electrons: 72 • Neutrons: Varies by isotope

Electron Configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d²

Discovery

1923 • Dirk Coster, George de Hevesy