Template:Infobox lanthanum

Lanthanum,  ₅₇La

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General properties
Pronunciation	Template:Infobox element/pronunciation
Appearance	silvery white
Standard atomic weight (Ar, standard)	Template:Infobox element/standard atomic weight
Mass number	Template:Infobox element/symbol-to-most-stable-isotope (most stable isotope)
Lanthanum in the periodic table
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Atomic number (Z)	57
Group	Template:Infobox element/group
Period	period 6
Block	d-block
Element category	Template:Infobox element/category format, sometimes considered a transition metal
Electron configuration	[Xe] 5d1 6s2
Electrons per shell	2, 8, 18, 18, 9, 2
Physical properties
Phase at STP	solid
Melting point	1193 K ​(920 °C, ​1688 °F)
Boiling point	3737 K ​(3464 °C, ​6267 °F)
Density (near r.t.)	6.162 g/cm3
when liquid (at m.p.)	5.94 g/cm3
Heat of fusion	6.20 kJ/mol
[[Enthalpy of vaporization|Heat of Template:Engvar]]	400 kJ/mol
Molar heat capacity	27.11 J/(mol·K)
[[Vapor pressure|Template:Engvar pressure]] (extrapolated) Template:Infobox element/vapor pressure table
Atomic properties
Oxidation states	Template:Infobox element/symbol-to-oxidation-state
Electronegativity	Pauling scale: 1.10
[[Ionization energy|Template:Engvar energies]]	1st: 538.1 kJ/mol 2nd: 1067 kJ/mol 3rd: 1850.3 kJ/mol
Atomic radius	empirical: 187 pm
Covalent radius	207±8 pm
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Other properties
Crystal structure	​Template:Infobox element/crystal structure Template:Infobox element/crystal structure
Speed of sound thin rod	2475 m/s (at 20 °C)
Thermal expansion	α, poly: 12.1 µm/(m·K) (at r.t.)
Thermal conductivity	13.4 W/(m·K)
Electrical resistivity	α, poly: 615 nΩ·m (at r.t.)
Magnetic ordering	paramagnetic
Magnetic susceptibility	+118.0·10−6 cm3/mol (298 K)
Young's modulus	α form: 36.6 GPa
Shear modulus	α form: 14.3 GPa
Bulk modulus	α form: 27.9 GPa
Poisson ratio	α form: 0.280
Mohs hardness	2.5
Vickers hardness	360–1750 MPa
Brinell hardness	350–400 MPa
CAS Number	7439-91-0
History
Discovery	Carl Gustaf Mosander (1838)
Main isotopes of lanthanum
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