Technical data for Silicon

Overview Name Silicon Symbol Si Atomic Number 14 Atomic Weight 28.085 Density 2.33 g/cm3 Melting Point 1414 °C Boiling Point 2900 °C Thermal properties Phase Solid Melting Point 1414 °C Boiling Point 2900 °C Absolute Melting Point 1687 K Absolute Boiling Point 3173 K Critical Pressure N/A Critical Temperature N/A Heat of Fusion 50.2 kJ/mol Heat of Vaporization 359 kJ/mol Specific Heat 710 J/(kg K)[note] Adiabatic Index N/A Neel Point N/A Thermal Conductivity 150 W/(m K) Thermal Expansion 2.6×10-6 K-1 Bulk physical properties Density 2.33 g/cm3 Density (Liquid) 2.57 g/cm3 Molar Volume 0.000012054 Brinell Hardness N/A Mohs Hardness 6.5 Vickers Hardness 9630.1303 MPa[note] Bulk Modulus 100 GPa Shear Modulus N/A Young Modulus 47 GPa Poisson Ratio N/A Refractive Index N/A Speed of Sound 2200 m/s Thermal Conductivity 150 W/(m K) Thermal Expansion 2.6×10-6 K-1 Reactivity Valence 4 Electronegativity 1.9 ElectronAffinity 133.6 kJ/mol Ionization Energies 786.5, 1577.1, 3231.6, 4355.5, 16091, 19805, 23780, 29287, 33878, 38726 kJ/mol Health and Safety DOT Hazard Class 4.1 DOT Numbers 1346 RTECS Number RTECSVW0400000 NFPA Label

Classifications Alternate Names None Names of Allotropes None Block p Group 14 Period 3 Series Metalloid Electron Configuration [Ne]3s23p2 Color Gray Discovery 1824 in Sweden Gas phase N/A CAS Number CAS7440-21-3 CID Number CID5461123 RTECS Number RTECSVW0400000 Electrical properties Electrical Type Semiconductor Electrical Conductivity 1000 S/m Resistivity 0.001 m Ω Superconducting Point N/A Magnetic properties Magnetic Type Diamagnetic Curie Point N/A Mass Magnetic Susceptibility -1.6×10-9 m3/Kg Molar Magnetic Susceptibility -4.49×10-11 m3/mol Volume Magnetic Susceptibility -3.73×10-6 Abundances % in Universe 0.07% % in Sun 0.09% % in Meteorites 14% % in Earth's Crust 27% % in Oceans 0.0001% % in Humans 0.026% Atomic dimensions and structure Atomic Radius 111 pm Covalent Radius 111 pm Van der Waals Radius 210 pm Crystal Structure Tetrahedral Packing Lattice Angles π/2, π/2, π/2 Lattice Constants 543.09, 543.09, 543.09 pm Space Group Name Fd_ 3m Space Group Number 227 Nuclear Properties Half-Life Stable Lifetime Stable Decay Mode N/A Quantum Numbers 3P0 Neutron Cross Section 0.166 Neutron Mass Absorption 0.0002 Known Isotopes 22Si, 23Si, 24Si, 25Si, 26Si, 27Si, 28Si, 29Si, 30Si, 31Si, 32Si, 33Si, 34Si, 35Si, 36Si, 37Si, 38Si, 39Si, 40Si, 41Si, 42Si, 43Si, 44Si Stable Isotopes 28Si, 29Si, 30Si Isotopic Abundances 28Si 92.2297% 29Si 4.6832% 30Si 3.0872%