General | States | Energies | Oxidation & Electrons |Appearance & Characteristics
Reactions | Other Forms |Radius | Conductivity | Abundance
Encyclopedia Britannica articles


Name Arsenic Symbol As
atomic number 33 Atomic weight 74.9216
Density @ 293 K 5.72 g/cm3 Atomic volume 13.1 cm3/mol
Group Non-Metal, Nitrogen group discovered 1600


state (s, l, g) s
melting point 886 K boiling point K
Heat of fusion ? Heat of vaporization 34.760 kJ/mol
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1st ionization energy 946.5 kJ/mole electronegativity 2.18
2nd ionization energy 1797.8 kJ/mole electron affinity 78 kJ/mole
3rd ionization energy 2735.4 kJ/mole Specific heat 0.33 J/gK
heat atomization 302 kJ/mole atoms

Oxidation & Electrons

Shells 2,8,18,5 electron configuration [Ar] 3d10 4s2 4p3
minimum oxidation number -3 maximum oxidation number 5
min. common oxidation no. -3 max. common oxidation no. 5
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Appearance & Characteristics

structure rhombohedral color gray
uses photocells (GaAs), poisons toxicity
hardness 3.5 mohs characteristics semimetal,brittle,3 forms


reaction with air mild, w/ht = As4O6 reaction with 6M HCl none
reaction with 6M HCl none reaction with 15M HNO3 mild, w/ht = H3AsO4, NOx
reaction with 6M NaOH none
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Other Forms

number of isotopes 1 hydride(s) AsH3
oxide(s) As2O3 chloride(s) AsCl3 AsCl5


ionic radius (2- ion) pm ionic radius (1- ion) pm
atomic radius 120 pm ionic radius (1+ ion) pm
ionic radius (2+ ion) pm ionic radius (3+ ion) 72 pm
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thermal conductivity 50.2 J/m-sec-deg electrical conductivity 30.03 1/mohm-cm
polarizability 4.3 A^3


source Arsenopyrite, enargite (misc) rel. abund. solar system 0.817 log
abundance earth's crust 0.3 log cost, pure 320 $/100g
cost, bulk $/100g
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World Wide Web presentation of Chemicool Periodic Table is © Copyright 1996-99 by David D. Hsu. Some data were provided by and used with the permission of JCE Software and is owned and copyright by the Division of Chemical Education, Inc. Additional data were provided by Perkin-Elmer through Peter Lykos of IIT. The information may not be redistributed without the permission of David Hsu or JCE Software.