Details : Item 215

Alkali metals
Alkaline earth metal
Transition metals I
Transition metals II
Transition metals III
Transition metals IV
Post-transition metal
Diatomic non-metal
Noble gas

Famille : Transition metals I/5
Symbol: Hf, period: solid, steel gray. Named after Hafnia
the Latin name for Copenhagen where it was discovered.
Used in filaments & electrodes.It is also a good material
for neutron absorption in nuclear power plants.
Atomic number72
Atomic weight178.49
Melting point (K)2506
Boiling point (K)4876
Speed of sound (m/s)3010
Discovery1922 (D. Coster)