Template:Infobox hafnium

Hafnium,  ₇₂Hf

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General properties
Pronunciation	Template:Infobox element/pronunciation
Appearance	steel gray
Standard atomic weight (Ar, standard)	Template:Infobox element/standard atomic weight
Mass number	Template:Infobox element/symbol-to-most-stable-isotope (most stable isotope)
Hafnium in the periodic table
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Atomic number (Z)	72
Group	Template:Infobox element/group
Period	period 6
Block	d-block
Element category	Template:Infobox element/category format
Electron configuration	[Xe] 4f14 5d2 6s2
Electrons per shell	2, 8, 18, 32, 10, 2
Physical properties
Phase at STP	solid
Melting point	2506 K ​(2233 °C, ​4051 °F)
Boiling point	4876 K ​(4603 °C, ​8317 °F)
Density (near r.t.)	13.31 g/cm3
when liquid (at m.p.)	12 g/cm3
Heat of fusion	27.2 kJ/mol
[[Enthalpy of vaporization|Heat of Template:Engvar]]	648 kJ/mol
Molar heat capacity	25.73 J/(mol·K)
[[Vapor pressure|Template:Engvar pressure]] Template:Infobox element/vapor pressure table
Atomic properties
Oxidation states	Template:Infobox element/symbol-to-oxidation-state
Electronegativity	Pauling scale: 1.3
[[Ionization energy|Template:Engvar energies]]	1st: 658.5 kJ/mol 2nd: 1440 kJ/mol 3rd: 2250 kJ/mol
Atomic radius	empirical: 159 pm
Covalent radius	175±10 pm
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Other properties
Crystal structure	​Template:Infobox element/crystal structure Template:Infobox element/crystal structure
Speed of sound thin rod	3010 m/s (at 20 °C)
Thermal expansion	5.9 µm/(m·K) (at 25 °C)
Thermal conductivity	23.0 W/(m·K)
Electrical resistivity	331 nΩ·m (at 20 °C)
Magnetic ordering	paramagnetic
Magnetic susceptibility	+75.0·10−6 cm3/mol (at 298 K)
Young's modulus	78 GPa
Shear modulus	30 GPa
Bulk modulus	110 GPa
Poisson ratio	0.37
Mohs hardness	5.5
Vickers hardness	1520–2060 MPa
Brinell hardness	1450–2100 MPa
CAS Number	7440-58-6
History
Naming	after Hafnia. Latin for: Copenhagen, where it was discovered
Prediction	Dmitri Mendeleev (1869)
Discovery and first isolation	Dirk Coster and George de Hevesy (1922)
Main isotopes of hafnium
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