Technical data for Lanthanum

Overview
NameLanthanum
SymbolLa
Atomic Number57
Atomic Weight138.9055
Density6.146 g/cm3
Melting Point920 °C
Boiling Point3464 °C

Thermal properties
PhaseSolid
Melting Point920 °C
Boiling Point3464 °C
Absolute Melting Point1193 K
Absolute Boiling Point3737 K
Heat of Fusion6.2 kJ/mol
Heat of Vaporization400 kJ/mol
Heat of CombustionN/A
Specific Heat195 J/(kg K)[note]
Thermal Conductivity13 W/(m K)
Thermal Expansion0.0000121 K-1

Bulk physical properties
Density6.146 g/cm3
Density (Liquid)5.94 g/cm3
Molar Volume0.000022601
Brinell Hardness363 MPa
Mohs Hardness2.5 MPa
Vickers Hardness491 MPa
Bulk Modulus28 GPa
Shear Modulus14 GPa
Young Modulus37 GPa
Poisson Ratio0.28
Speed of Sound2475 m/s
Thermal Conductivity13 W/(m K)
Thermal Expansion0.0000121 K-1

Reactivity
Valence3
Electronegativity1.1
ElectronAffinity48 kJ/mol
Ionization Energies
538.1, 1067, 1850.3, 4819, 5940 kJ/mol

Health and Safety
Autoignition PointN/A
FlashpointN/A

Classifications
Alternate NamesNone
Nams of AllotropesNone
Blockf
GroupN/A
Period6
Electron Configuration[Xe]5d16s2
ColorSilver
Discovery
1839 in Sweden
Gas phaseN/A
CAS NumberCAS7439-91-0

Electrical properties
Electrical TypeConductor
Electrical Conductivity1.6×106 S/m
Resistivity6.1×10-7 m Ω
Superconducting Point4.88

Magnetic properties
Magnetic TypeN/A
Mass Magnetic Susceptibility1.1×10-8
Molar Magnetic Susceptibility1.528×10-9
Volume Magnetic Susceptibility0.00006761

Abundances
% in Universe2×10-7%
% in Sun2×10-7%
% in Meteorites0.000028%
% in Earth's Crust0.0034%
% in Oceans3.4×10-10%
% in HumansN/A

Atomic dimensions and structure
Atomic RadiusN/A
Covalent Radius169 pm
Van der Waals RadiusN/A
Crystal StructureSimple Hexagonal
Lattice Angles
π/2, π/2, 2 π/3
Lattice Constants
377.2, 377.2, 1214.4 pm
Space Group NameP63/mmc
Space Group Number194

Nuclear Properties
Half-LifeStable
LifetimeStable
Stable Isotopes
139La
Isotopic Abundances
138La0.09%
139La99.91%

Notes on the properties of Lanthanum:
Specific Heat: Value given for solid phase.