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Technical data for Thulium

Click any property name to see plots of that property for all the elements.

Overview
NameThulium
SymbolTm
Atomic Number69
Atomic Weight168.93422
Density9.32 g/cm3
Melting Point1545 °C
Boiling Point1950 °C

Thermal properties
PhaseSolid
Melting Point1545 °C
Boiling Point1950 °C
Absolute Melting Point1818 K
Absolute Boiling Point2223 K
Critical PressureN/A
Critical TemperatureN/A
Heat of Fusion16.8 kJ/mol
Heat of Vaporization250 kJ/mol
Specific Heat160 J/(kg K)[note]
Adiabatic IndexN/A
Neel Point56 K
Thermal Conductivity17 W/(m K)
Thermal Expansion0.0000133 K-1

Bulk physical properties
Density9.32 g/cm3
Density (Liquid)8.56 g/cm3
Molar Volume0.000018126
Brinell Hardness471 MPa
Mohs Hardness1.77[note]
Vickers Hardness520 MPa
Bulk Modulus45 GPa
Shear Modulus31 GPa
Young Modulus74 GPa
Poisson Ratio0.21
Refractive IndexN/A
Speed of SoundN/A
Thermal Conductivity17 W/(m K)
Thermal Expansion0.0000133 K-1

Reactivity
Valence3
Electronegativity1.25
ElectronAffinity50 kJ/mol
Ionization Energies
596.7, 1160, 2285, 4120 kJ/mol

Health and Safety
DOT Hazard Class
4.1
DOT Numbers3089
RTECS NumberN/A
NFPA LabelN/A

Classifications
Alternate NamesNone
Names of AllotropesNone
Blockf
GroupN/A
Period6
SeriesLanthanide
Electron Configuration[Xe]6s24f13
ColorSilver
Discovery
1879 in Sweden
Gas phaseN/A
CAS NumberCAS7440-30-4
CID Number
CID23961
RTECS NumberN/A

Electrical properties
Electrical TypeConductor
Electrical Conductivity1.4×106 S/m
Resistivity7×10-7 m Ω
Superconducting PointN/A

Magnetic properties
Magnetic TypeParamagnetic
Curie Point25 K
Mass Magnetic Susceptibility1.99×10-6 m3/Kg
Molar Magnetic Susceptibility3.36179×10-7 m3/mol
Volume Magnetic Susceptibility0.0185488

Abundances
% in Universe1×10-8%
% in Sun2×10-8%
% in Meteorites2.9×10-6%
% in Earth's Crust0.000045%
% in Oceans2×10-11%
% in HumansN/A

Atomic dimensions and structure
Atomic Radius222 pm
Covalent Radius190 pm
Van der Waals RadiusN/A
Crystal StructureSimple Hexagonal
Lattice Angles
π/2, π/2, 2 π/3
Lattice Constants
353.75, 353.75, 555.46 pm
Space Group NameP63/mmc
Space Group Number194

Nuclear Properties
Half-LifeStable
LifetimeStable
Decay ModeN/A
Quantum Numbers2F7/2
Neutron Cross Section105
Neutron Mass Absorption0.025
Known Isotopes
145Tm, 146Tm, 147Tm, 148Tm, 149Tm, 150Tm, 151Tm, 152Tm, 153Tm, 154Tm, 155Tm, 156Tm, 157Tm, 158Tm, 159Tm, 160Tm, 161Tm, 162Tm, 163Tm, 164Tm, 165Tm, 166Tm, 167Tm, 168Tm, 169Tm, 170Tm, 171Tm, 172Tm, 173Tm, 174Tm, 175Tm, 176Tm, 177Tm, 178Tm, 179Tm
Stable Isotopes
169Tm
Isotopic Abundances
169Tm100%


Notes on the properties of Thulium:

Mohs Hardness: converted from Vickers scale

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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