Technical data for Thallium

Overview
NameThallium
SymbolTl
Atomic Number81
Atomic Weight204.3833
Density11.85 g/cm3
Melting Point304 °C
Boiling Point1473 °C

Thermal properties
PhaseSolid
Melting Point304 °C
Boiling Point1473 °C
Absolute Melting Point577 K
Absolute Boiling Point1746 K
Heat of Fusion4.2 kJ/mol
Heat of Vaporization165 kJ/mol
Heat of CombustionN/A
Specific Heat129 J/(kg K)[note]
Thermal Conductivity46 W/(m K)
Thermal Expansion0.0000299 K-1

Bulk physical properties
Density11.85 g/cm3
Density (Liquid)11.22 g/cm3
Molar Volume0.0000172475
Brinell Hardness26.4 MPa
Mohs Hardness1.2 MPa
Bulk Modulus43 GPa
Shear Modulus2.8 GPa
Young Modulus8 GPa
Poisson Ratio0.45
Speed of Sound818 m/s
Thermal Conductivity46 W/(m K)
Thermal Expansion0.0000299 K-1

Reactivity
Valence3
Electronegativity1.62
ElectronAffinity19.2 kJ/mol
Ionization Energies
589.4, 1971, 2878 kJ/mol

Health and Safety
Autoignition PointN/A
FlashpointN/A

Classifications
Alternate NamesNone
Nams of AllotropesNone
Blockp
Group13
Period6
Electron Configuration[Xe]4f145d106s26p1
ColorSilver
Discovery
1861 in United Kingdom
Gas phaseN/A
CAS NumberCAS7440-28-0

Electrical properties
Electrical TypeConductor
Electrical Conductivity6.7×106 S/m
Resistivity1.5×10-7 m Ω
Superconducting Point2.38

Magnetic properties
Magnetic TypeDiamagnetic
Curie PointN/A
Mass Magnetic Susceptibility-3×10-9
Molar Magnetic Susceptibility-6.13×10-10
Volume Magnetic Susceptibility-0.0000356

Abundances
% in Universe5×10-8%
% in Sun1×10-7%
% in Meteorites7.8×10-6%
% in Earth's Crust0.000053%
% in Oceans1×10-10%
% in HumansN/A

Atomic dimensions and structure
Atomic Radius156 pm
Covalent Radius148 pm
Van der Waals Radius196 pm
Crystal StructureSimple Hexagonal
Lattice Angles
π/2, π/2, 2 π/3
Lattice Constants
345.66, 345.66, 552.48 pm
Space Group NameP63/mmc
Space Group Number194

Nuclear Properties
Half-LifeStable
LifetimeStable
Stable Isotopes
203Tl, 205Tl
Isotopic Abundances
203Tl29.524%
205Tl70.476%

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