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Technical data for Lanthanum

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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
Critical PressureN/A
Critical TemperatureN/A
Heat of Fusion6.2 kJ/mol
Heat of Vaporization400 kJ/mol
Heat of CombustionN/A
Specific Heat195 J/(kg K)[note]
Adiabatic IndexN/A
Neel PointN/A
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
Refractive IndexN/A
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
Heat of CombustionN/A
DOT Hazard Class4.1
DOT Numbers3178
EU NumberN/A
NFPA Fire RatingN/A
NFPA HazardsN/A
NFPA Health RatingN/A
NFPA Reactivity RatingN/A
RTECS NumberN/A
NFPA LabelN/A

Classifications
Alternate NamesNone
Names of AllotropesNone
Blockf
GroupN/A
Period6
Electron Configuration[Xe]5d16s2
ColorSilver
Discovery
1839 in Sweden
Gas phaseN/A
CAS NumberCAS7439-91-0
CID NumberCID23926
Gmelin NumberN/A
NSC NumberN/A
RTECS NumberN/A

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

Magnetic properties
Magnetic TypeParamagnetic
Curie PointN/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
Decay ModeN/A
Quantum Numbers2D3/2
Neutron Cross Section8.98
Neutron Mass Absorption0.0023
Known Isotopes
117La, 118La, 119La, 120La, 121La, 122La, 123La, 124La, 125La, 126La, 127La, 128La, 129La, 130La, 131La, 132La, 133La, 134La, 135La, 136La, 137La, 138La, 139La, 140La, 141La, 142La, 143La, 144La, 145La, 146La, 147La, 148La, 149La, 150La, 151La, 152La, 153La, 154La, 155La
Stable Isotopes
139La
Isotopic Abundances
138La0.09%
139La99.91%


Notes on the properties of Lanthanum:

Specific Heat: Value given for solid phase.

Up to date, curated data provided by
Mathematica's ElementData function from Wolfram Research, Inc.

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