Hafnium (Hf) » Innovachem

Isotope	Z(p)	N(n)	Atomic Mass	Natural Abundance	Enrichment Level	Chemical Form
Hf-174	72	102	173.940042	0.162%	13.46%	Oxide
Hf-176	72	104	175.941406	5.260%	84.60%	Oxide
Hf-177	72	105	176.943220	18.606%	85.40%	Oxide
Hf-178	72	106	177.943698	27.297%	92.40%	Oxide
Hf-179	72	107	178.945815	13.629%	75.00%	Oxide
Hf-180	72	108	179.946549	35.100%	≥94.60%	Oxide

Name	Hafnium
Symbol	Hf
Atomic number	72
Atomic weight	178.49
Standard state	Solid at 298 ºK
CAS Registry ID	7440-58-6
Group in periodic table	4
Group name	None
Period in periodic table	6
Block in periodic table	d-block
Color	Gray steel
Classification	Metallic
Melting point	2233 °C
Boiling point	4602 °C
Vaporization point	2233 ºC
Thermal conductivity	23.0 W/(m·K) at 298.2 ºK
Electrical resistivity	35.1 µΩ·cm at 25 ºC
Electronegativity	1.3
Specific heat	0.14 kJ/kg K
Heat of vaporization	630 kJ·mol^-1 at 4602 ºC
Heat of fusion	25.5 kJ·mol^-1 mole
Density of liquid	12 g/cm³ at 2233 °C
Density of solid	13.31 g/cm³
Electron configuration	[Xe]4f¹⁴5d²6s²
Atomic radius	1.442 Å
Common oxidation state	+4 (also exhibits oxidation states +2 and +3)