Technical data for Potassium

Overview
NamePotassium
SymbolK
Atomic Number19
Atomic Weight39.0983
Density0.856 g/cm3
Melting Point63.38 °C
Boiling Point759 °C

Thermal properties
PhaseSolid
Melting Point63.38 °C
Boiling Point759 °C
Absolute Melting Point336.53 K
Absolute Boiling Point1032 K
Critical Presure16 MPa (157.9 Atm)[note]
Critical Temperature2223 K[note]
Heat of Fusion2.33 kJ/mol
Heat of Vaporization76.9 kJ/mol
Heat of Combustion-182 J/(kg K)
Specific Heat757 J/(kg K)[note]
Thermal Conductivity100 W/(m K)
Thermal ExpansionN/A

Bulk physical properties
Density0.856 g/cm3
Density (Liquid)0.828 g/cm3
Molar Volume0.00004568
Brinell Hardness0.363 MPa
Mohs Hardness0.4 MPa
Vickers HardnessN/A
Bulk Modulus3.1 GPa
Shear Modulus1.3 GPa
Speed of Sound2×103 m/s
Thermal Conductivity100 W/(m K)
Thermal ExpansionN/A

Reactivity
Valence1
Electronegativity0.82
ElectronAffinity48.4 kJ/mol
Ionization Energies
418.8, 3052, 4420, 5877, 7975, 9590, 11343, 14944, 16963.7, 48610 kJ/mol

Health and Safety
Autoignition Point440 °C
FlashpointN/A

Classifications
Alternate NamesKalium
Nams of AllotropesNone
Blocks
Group1
Period4
Electron Configuration[Ar]4s1
ColorSilver
Discovery
1807 in United Kingdom
Gas phaseN/A
CAS NumberCAS7440-09-7

Electrical properties
Electrical TypeConductor
Electrical Conductivity1.4×107 S/m
Resistivity7×10-8 m Ω
Superconducting PointN/A

Magnetic properties
Magnetic TypeN/A
Curie PointN/A
Mass Magnetic Susceptibility6.7×10-9
Molar Magnetic Susceptibility2.62×10-10
Volume Magnetic Susceptibility5.74×10-6

Abundances
% in Universe0.0003%
% in Sun0.0004%
% in Meteorites0.07%
% in Earth's Crust1.5%
% in Oceans0.042%
% in Humans0.2%

Atomic dimensions and structure
Atomic Radius243 pm
Covalent Radius196 pm
Van der Waals Radius275 pm
Crystal StructureBody Centered Cubic
Lattice Angles
π/2, π/2, π/2
Lattice Constants
532.8, 532.8, 532.8 pm
Space Group NameIm_ 3m
Space Group Number229

Nuclear Properties
Half-LifeStable
LifetimeStable
Stable Isotopes
39K, 41K
Isotopic Abundances
39K93.2581%
40K0.0117%
41K6.7302%

Notes on the properties of Potassium:
Critical Pressure: Value estimated based on extrapolation.
Critical Temperature: Value estimated based on extrapolation.
Specific Heat: Value given for solid phase.