Technical data for Chromium

Overview Name Chromium Symbol Cr Atomic Number 24 Atomic Weight 51.9961 Density 7.19 g/cm3 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 20.5 kJ/mol Heat of Vaporization 339 kJ/mol Specific Heat 448 J/(kg K)[note] Adiabatic Index N/A Neel Point 393 K Thermal Conductivity 94 W/(m K) Thermal Expansion 4.9×10-6 K-1 Bulk physical properties Density 7.19 g/cm3 Density (Liquid) 6.3 g/cm3 Molar Volume 7.2317×10-6 Brinell Hardness 1120 MPa Mohs Hardness 8.5 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 4.9×10-6 K-1 Reactivity Valence 6 Electronegativity 1.66 ElectronAffinity 64.3 kJ/mol Ionization Energies 652.9, 1590.6, 2987, 4743, 6702, 8744.9, 15455, 17820, 20190, 23580, 26130, 28750, 34230, 37066, 97510, 105800, 114300, 125300, 134700, 144300, 157700 kJ/mol Health and Safety DOT Hazard Class 4.1 DOT Numbers 3089 RTECS Number RTECSGB4200000 NFPA Label

Classifications Alternate Names None Names of Allotropes None Block d Group 6 Period 4 Series Transition Metal Electron Configuration [Ar]4s13d5 Color Silver Discovery 1797 in France Gas phase N/A CAS Number CAS7440-47-3 CID Number CID23976 RTECS Number RTECSGB4200000 Electrical properties Electrical Type Conductor Electrical Conductivity 7.9×106 S/m Resistivity 1.3×10-7 m Ω Superconducting Point N/A Magnetic properties Magnetic Type Antiferromagnetic Curie Point N/A Mass Magnetic Susceptibility 4.45×10-8 m3/Kg Molar Magnetic Susceptibility 2.314×10-9 m3/mol 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 139 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%