Technical data for Chromium

Overview Name Chromium Symbol Cr Atomic Number 24 Atomic Weight 51.9961 Density 7.14 g/cc Melting Point 1907.°C Boiling Point 2671.°C Thermal properties Phase Solid Melting Point 1907.°C Boiling Point 2671.°C Absolute Melting Point 2180.K Absolute Boiling Point 2944.K Critical Pressure N/A Critical Temperature N/A Heat of Fusion 20.5KJ/mol Heat of Vaporization 339.KJ/mol Heat of Combustion N/A Specific Heat 448.J/(Kg K)[note] Adiabatic Index N/A Neel Point 393.K Thermal Conductivity 94.W/(m K) Thermal Expansion 4.9×10-6K-1 Bulk physical properties Density 7.14 g/cc Density (Liquid) 6.3 g/cc Molar Volume 7.2824×10-6 Brinell Hardness 1120.MPa Mohs Hardness 8.5MPa Vickers Hardness 1060.MPa Bulk Modulus 160.GPa Shear Modulus 115.GPa Young Modulus 279.GPa Poisson Ratio 0.21 Refractive Index N/A Speed of Sound 5940.m/s Thermal Conductivity 94.W/(m K) Thermal Expansion 4.9×10-6K-1 Reactivity Valence 6 Electronegativity 1.66 ElectronAffinity 64.3KJ/mol Ionization Energies 652.9, 1590.6, 2987., 4743., 6702., 8744.9, 15455., 17820., 20190., 23580., 26130., 28750., 34230., 37066., 97510., 1.058×105, 1.143×105, 1.253×105, 1.347×105, 1.443×105, 1.577×105 KJ/mol Health and Safety Autoignition Point 400.°C Flashpoint N/A Heat of Combustion N/A DOT Hazard Class 4.1 DOT Numbers 3089 EU Number EU231-157-5 NFPA Fire Rating 1 NFPA Hazards N/A NFPA Health Rating 2 NFPA Reactivity Rating 1 RTECS Classes Tumorigen, Mutagen RTECS Number RTECSGB4200000 NFPA Label

Classifications Alternate Names None Names of Allotropes None Block d Group 6 Period 4 Electron Configuration [Ar]3d54s1 Color Silver Discovery 1797 in France Gas phase N/A CAS Number 7440-47-3 CID Number CID23976 Gmelin Number Gmelin16274 NSC Number N/A RTECS Number RTECSGB4200000 Electrical properties Electrical Type Conductor Electrical Conductivity 7.9×106S/m Resistivity 1.3×10-7m Ω Superconducting Point N/A Magnetic properties Magnetic Type Antiferromagnetic Curie Point N/A Mass Magnetic Susceptibility 4.45×10-8 Molar Magnetic Susceptibility 2.314×10-9 Volume Magnetic Susceptibility 0.0003177 Abundances % in Universe 0.0015% % in Sun 0.002% % in Meteorites 0.3% % in Earth's Crust 0.014% % in Oceans 6.×10-8% % in Humans 3.×10-6% Atomic dimensions and structure Atomic Radius 166.pm Covalent Radius 127.pm Van der Waals Radius N/A Crystal Structure Body Centered Cubic Lattice Angles π/2, π/2, π/2 Lattice Constants 291., 291., 291. pm Space Group Name Im_ 3m Space Group Number 229 Nuclear Properties Half-Life Stable Lifetime Stable Decay Mode N/A Quantum Numbers 7S3 Neutron Cross Section 3.1 Neutron Mass Absorption 0.0021 Known Isotopes 42Cr, 43Cr, 44Cr, 45Cr, 46Cr, 47Cr, 48Cr, 49Cr, 50Cr, 51Cr, 52Cr, 53Cr, 54Cr, 55Cr, 56Cr, 57Cr, 58Cr, 59Cr, 60Cr, 61Cr, 62Cr, 63Cr, 64Cr, 65Cr, 66Cr, 67Cr Stable Isotopes 50Cr, 52Cr, 53Cr, 54Cr Isotopic Abundances 50Cr 4.345% 52Cr 83.789% 53Cr 9.501% 54Cr 2.365%