Latin nameHafnium
English nameHafnium
chemical symbolHf
atomic number72
relative atomic mass178,49
classificationtransition metals
discovery year1923
discovererD. Coster,
G. von Hevesey
melting point [°C]2227
boiling point [°C]4602
density [g cm-3]13,2
density at melting point [g cm-3]12,0
electronegativity [Pauling]1,3
oxidation statesII, III, IV
electron configuration[Xe]4f14 5d2 6s2
atomic radius [pm]208
covalent radius [pm]150
specific heat [J g-1K-1]0,14
heat of fusion [kJ mol-1]24,06
thermal conductivity [W m-1 K-1]23
el. conductivity [S m-1]3,3.106
1. ionizing potential [eV]6,8251
2. ionizing potential [eV]14,925
3. ionizing potential [eV]23,32
Mohs hardness5,5
Vickers hardness [MPa]1760
Brinell hardness [MPa]1700
shear modulus [GPa]30
Young's modulus [GPa]78
point of superconductivity [K]0,128
state at normal conditionssolid

Hafnium is a ductile metal with a silver luster. Hafnium has been successfully alloyed with other metals.