Technical data for Arsenic

Overview Name Arsenic Symbol As Atomic Number 33 Atomic Weight 74.9216 Density 5.727 g/cm3 Melting Point 817 °C Boiling Point 614 °C[note] Thermal properties Phase Solid Melting Point 817 °C Boiling Point 614 °C[note] Absolute Melting Point 1090 K Absolute Boiling Point 887 K Critical Pressure N/A Critical Temperature N/A Heat of Fusion 27.7 kJ/mol Heat of Vaporization 32.4 kJ/mol Heat of Combustion {"N/A", "N/A", "N/A"} J/(kg K) Specific Heat 328 J/(kg K)[note] Adiabatic Index N/A Neel Point N/A Thermal Conductivity 50 W/(m K) Thermal Expansion N/A Bulk physical properties Density 5.727 g/cm3 Density (Liquid) 5.22 g/cm3 Molar Volume 0.000013082 Brinell Hardness 1440 MPa Mohs Hardness 3.5 MPa Vickers Hardness N/A Bulk Modulus 22 GPa Shear Modulus N/A Young Modulus 8 GPa Poisson Ratio N/A Refractive Index 1.001552 Speed of Sound N/A Thermal Conductivity 50 W/(m K) Thermal Expansion N/A Reactivity Valence 5 Electronegativity 2.18 ElectronAffinity 78 kJ/mol Ionization Energies 947, 1798, 2735, 4837, 6043, 12310 kJ/mol Health and Safety Autoignition Point N/A Flashpoint N/A[note] Heat of Combustion {"N/A", "N/A", "N/A"} J/(kg K) DOT Hazard Class {N/A, 6.1, N/A} DOT Numbers "N/A", {1558}, "N/A" EU Number {N/A, N/A, N/A} NFPA Fire Rating {N/A, 2, N/A} NFPA Hazards N/ A, N/ A, N/ A NFPA Health Rating {N/A, 3, N/A} NFPA Reactivity Rating {N/A, N/A, N/A} RTECS Number {N/A, RTECSCG0525000, N/A} NFPA Label [note]

Classifications Alternate Names None Names of Allotropes YellowArsenic, BlackArsenic, GrayArsenic Block p Group 15 Period 4 Electron Configuration [Ar]3d104s24p3 Color Silver Discovery 1250 Gas phase N/A CAS Number CAS7440-38-2 CID Number {CID5359596, CID5359596, CID139279} Gmelin Number {N/A, N/A, N/A} NSC Number {N/A, N/A, N/A} RTECS Number {N/A, RTECSCG0525000, N/A} Electrical properties Electrical Type Conductor Electrical Conductivity 3.3×106 S/m Resistivity 3×10-7 m Ω Superconducting Point N/A Magnetic properties Magnetic Type Diamagnetic Curie Point N/A Mass Magnetic Susceptibility -3.9×10-9 Molar Magnetic Susceptibility -2.92×10-10 Volume Magnetic Susceptibility -0.0000223 Abundances % in Universe 8×10-7% % in Sun N/A % in Meteorites 0.00018% % in Earth's Crust 0.00021% % in Oceans 2.3×10-7% % in Humans 5×10-6% Atomic dimensions and structure Atomic Radius 114 pm Covalent Radius 119 pm Van der Waals Radius 185 pm Crystal Structure Simple Trigonal Lattice Angles π/2, π/2, 2 π/3 Lattice Constants 375.98, 375.98, 1054.75 pm Space Group Name R_ 3m Space Group Number 166 Nuclear Properties Half-Life Stable Lifetime Stable Decay Mode N/A Quantum Numbers 4S3/2 Neutron Cross Section 4.3 Neutron Mass Absorption 0.002 Known Isotopes 60As, 61As, 62As, 63As, 64As, 65As, 66As, 67As, 68As, 69As, 70As, 71As, 72As, 73As, 74As, 75As, 76As, 77As, 78As, 79As, 80As, 81As, 82As, 83As, 84As, 85As, 86As, 87As, 88As, 89As, 90As, 91As, 92As Stable Isotopes 75As Isotopic Abundances 75As 100%