Technical data for Potassium

Overview Name Potassium Symbol K Atomic Number 19 Atomic Weight 39.0983 Density 0.856 g/cm3 Melting Point 63.38 °C Boiling Point 759 °C Thermal properties Phase Solid Melting Point 63.38 °C Boiling Point 759 °C Absolute Melting Point 336.53 K Absolute Boiling Point 1032 K Critical Pressure 16 MPa (157.9 Atm)[note] Critical Temperature 2223 K[note] Heat of Fusion 2.33 kJ/mol Heat of Vaporization 76.9 kJ/mol Specific Heat 757 J/(kg K)[note] Adiabatic Index N/A Neel Point N/A Thermal Conductivity 100 W/(m K) Thermal Expansion N/A Bulk physical properties Density 0.856 g/cm3 Density (Liquid) 0.828 g/cm3 Molar Volume 0.00004568 Brinell Hardness 0.363 MPa Mohs Hardness 0.4 Vickers Hardness N/A Bulk Modulus 3.1 GPa Shear Modulus 1.3 GPa Young Modulus N/A Poisson Ratio N/A Refractive Index N/A Speed of Sound 2000 m/s Thermal Conductivity 100 W/(m K) Thermal Expansion N/A Reactivity Valence 1 Electronegativity 0.82 ElectronAffinity 48.4 kJ/mol Ionization Energies 418.8, 3052, 4420, 5877, 7975, 9590, 11343, 14944, 16963.7, 48610 kJ/mol Health and Safety DOT Hazard Class 4.3 DOT Numbers 2257 RTECS Number RTECSTS6460000 NFPA Label

Classifications Alternate Names Kalium Names of Allotropes None Block s Group 1 Period 4 Series Alkali Metal Electron Configuration [Ar]4s1 Color Silver Discovery 1807 in The United Kingdom Gas phase N/A CAS Number CAS7440-09-7 CID Number CID5462222 RTECS Number RTECSTS6460000 Electrical properties Electrical Type Conductor Electrical Conductivity 1.4×107 S/m Resistivity 7.000000000002×10-8 m Ω Superconducting Point N/A Magnetic properties Magnetic Type Paramagnetic Curie Point N/A Mass Magnetic Susceptibility 6.7×10-9 m3/Kg Molar Magnetic Susceptibility 2.62×10-10 m3/mol Volume Magnetic Susceptibility 5.74×10-6 Abundances % in Universe 0.0003% % in Sun 0.0004% % in Meteorites 0.07% % in Earth's Crust 1.5% % in Oceans 0.042% % in Humans 0.2% Atomic dimensions and structure Atomic Radius 243 pm Covalent Radius 203 pm Van der Waals Radius 275 pm Crystal Structure Body-centered Cubic Lattice Angles π/2, π/2, π/2 Lattice Constants 532.8, 532.8, 532.8 pm Space Group Name Im_ 3m Space Group Number 229 Nuclear Properties Half-Life Stable Lifetime Stable Decay Mode N/A Quantum Numbers 2S1/2 Neutron Cross Section 2.1 Neutron Mass Absorption 0.0018 Known Isotopes 32K, 33K, 34K, 35K, 36K, 37K, 38K, 39K, 40K, 41K, 42K, 43K, 44K, 45K, 46K, 47K, 48K, 49K, 50K, 51K, 52K, 53K, 54K, 55K Stable Isotopes 39K, 41K Isotopic Abundances 39K 93.2581% 40K 0.0117% 41K 6.7302%