Hafnium (thing)

(So named (Modern Latin Hafnia, "Copenhagen") in 1923 by D. Coster, Dutch chemist, and G. C. de Hevesy, Hungarian chemist after where it was discovered) A metallic chemical element found with, and similar to, zirconium. It is used in the manufacture of light-bulb filaments and in reactor control rods.

Symbol: Hf
Atomic number: 72
Atomic weight: 178.49
Density (at room temperature and pressure): 13.31 g/cc
Melting point: 2,230°C
Boiling point: 4,603°C
Valence: +4
Ground state electron configuration: [Xe]4f¹⁴5d²6s²