Hafnium

Hafnium 178.49(2)   Hf 72 1s22s22p63s23p63d104s24p6 4d105s25p64f145d26s2 [ ? ] Transition metal: Properties: Shiny, steel gray, ductile metal. Hazard: Pyrophoric and will ignite spontaneously in the air.

Hafnium is a chemical element, having the chemical symbol Hf. Its atomic number (the number of protons) is 72. It has a standard atomic weight of 178.49 g•mol ⁻¹ and is a solid in its elemental form.

Hafnium is considered a member of the "Transition metal" class of elements. At a pressure of 101.325 kPa, it has a boiling point of 4,603°C and a melting point of 2,233 °C.