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Technical data for Lanthanum

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Overview
NameLanthanum
SymbolLa
Atomic Number57
Atomic Weight138.90547
Density6.146 g/cm3
Melting Point919 °C
Boiling Point3464 °C

Thermal properties
PhaseSolid
Melting Point919 °C
Boiling Point3464 °C
Absolute Melting Point1193 K
Absolute Boiling Point3737 K
Critical PressureN/A
Critical TemperatureN/A
Heat of Fusion6.3 kJ/mol
Heat of Vaporization400 kJ/mol
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
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
DOT Hazard Class
4.1
DOT Numbers3178
RTECS NumberN/A
NFPA LabelN/A

Classifications
Alternate NamesNone
Names of AllotropesNone
Blockf
GroupN/A
Period6
SeriesLanthanide
Electron Configuration[Xe]6s25d1
ColorSilver
Discovery
1839 in Sweden
Gas phaseN/A
CAS NumberCAS7439-91-0
CID Number
CID23926
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 m3/Kg
Molar Magnetic Susceptibility1.528×10-9 m3/mol
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 Radius207 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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