Arsenic, 33As
Arsenic
Pronunciation
Allotropesgrey (most common), yellow, black (see Allotropes of arsenic)
Appearancemetallic grey
Standard atomic weight Ar°(As)
Arsenic in the periodic table
Hydrogen Helium
Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon
Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon
Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon
Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon
Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson
P

As

Sb
germaniumarsenicselenium
Atomic number (Z)33
Groupgroup 15 (pnictogens)
Periodperiod 4
Block  p-block
Electron configuration[Ar] 3d10 4s2 4p3
Electrons per shell2, 8, 18, 5
Physical properties
Phase at STPsolid
Sublimation point887 K ​(615 °C, ​1137 °F)
Density (at 20° C)grey: 5.782 g/cm3[3]
when liquid (at m.p.)5.22 g/cm3
Triple point1090 K, ​3628 kPa[4]
Critical point1673 K, ? MPa
Heat of fusiongrey: 24.44 kJ/mol
Heat of vaporization34.76 kJ/mol (?)
Molar heat capacity24.64 J/(mol·K)
Vapor pressure
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 553 596 646 706 781 874
Atomic properties
Oxidation statescommon: −3, +3, +5
−2,[5] −1,[6] 0,[7] +1,[8] +2,[9] +4[10]
ElectronegativityPauling scale: 2.18
Ionization energies
  • 1st: 947.0 kJ/mol
  • 2nd: 1798 kJ/mol
  • 3rd: 2735 kJ/mol
  • (more)
Atomic radiusempirical: 119 pm
Covalent radius119±4 pm
Van der Waals radius185 pm
Color lines in a spectral range
Spectral lines of arsenic
Other properties
Natural occurrenceprimordial
Crystal structuregrey: ​rhombohedral (hR2)
Lattice constants
Rhombohedral crystal structure for grey: arsenic
ar = 413.15 pm
α = 54.133° pm ah = 375.99 pm
ch = 1054.58 pm (at 20 °C)[3]
Thermal expansion5.6 µm/(m⋅K)[11] (at r.t.)
Thermal conductivity50.2 W/(m⋅K)
Electrical resistivity333 nΩ⋅m (at 20 °C)
Magnetic orderingdiamagnetic[12]
Molar magnetic susceptibility−5.5×10−6 cm3/mol[13]
Young's modulus8 GPa
Bulk modulus22 GPa
Mohs hardness3.5
Brinell hardness1440 MPa
CAS Number7440-38-2
History
DiscoveryArabic alchemists (before AD 815)
Isotopes of arsenic
Main isotopes[14] Decay
abun­dance half-life (t1/2) mode pro­duct
73As synth 80.3 d ε 73Ge
γ
74As synth 17.8 d ε 74Ge
β+ 74Ge
γ
β 74Se
75As 100% stable
 Category: Arsenic
| references
As · Arsenic
Ge ←

ibox Ge

iso
33
As  [e]
IB-As [e]
IBisos [e]
→ Se

ibox Se

indexes by PT (page)
child table, as reused in {IB-As}
Main isotopes of arsenic
Main isotopes[14] Decay
abun­dance half-life (t1/2) mode pro­duct
73As synth 80.3 d ε 73Ge
γ
74As synth 17.8 d ε 74Ge
β+ 74Ge
γ
β 74Se
75As 100% stable
Data sets read by {{Infobox element}}
Name and identifiers
Symbol etymology (11 non-trivial)
Top image (caption, alt)
Pronunciation
Allotropes (overview)
Group (overview)
Period (overview)
Block (overview)
Natural occurrence
Phase at STP
Oxidation states
Spectral lines image
Electron configuration (cmt, ref)
Isotopes
Standard atomic weight
  most stable isotope
Wikidata
Wikidata *
* Not used in {{Infobox element}} (2023-01-01)
See also {{Index of data sets}} · Cat:data sets (46) · (this table: )

References

  1. ^ "Standard Atomic Weights: Arsenic". CIAAW. 2013.
  2. ^ Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (2022-05-04). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN 1365-3075.
  3. ^ a b Arblaster, John W. (2018). Selected Values of the Crystallographic Properties of Elements. Materials Park, Ohio: ASM International. ISBN 978-1-62708-155-9.
  4. ^ Gokcen, N. A (1989). "The As (arsenic) system". Bull. Alloy Phase Diagrams. 10: 11–22. doi:10.1007/BF02882166.
  5. ^ As(−2) has been observed in CaAs; see Holleman, Arnold F.; Wiberg, Egon; Wiberg, Nils (2008). Lehrbuch der Anorganischen Chemie (in German) (102 ed.). Walter de Gruyter. p. 829. ISBN 9783110206845.
  6. ^ As(−1) has been observed in LiAs; see Reinhard Nesper (1990). "Structure and chemical bonding in zintl-phases containing lithium". Progress in Solid State Chemistry (1): 1–45. doi:10.1016/0079-6786(90)90006-2.
  7. ^ Abraham, Mariham Y.; Wang, Yuzhong; Xie, Yaoming; Wei, Pingrong; Shaefer III, Henry F.; Schleyer, P. von R.; Robinson, Gregory H. (2010). "Carbene Stabilization of Diarsenic: From Hypervalency to Allotropy". Chemistry: A European Journal. 16 (2): 432–5. doi:10.1002/chem.200902840. PMID 19937872.
  8. ^ Ellis, Bobby D.; MacDonald, Charles L. B. (2004). "Stabilized Arsenic(I) Iodide: A Ready Source of Arsenic Iodide Fragments and a Useful Reagent for the Generation of Clusters". Inorganic Chemistry. 43 (19): 5981–6. doi:10.1021/ic049281s. PMID 15360247.
  9. ^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 28. ISBN 978-0-08-037941-8.
  10. ^ As(IV) has been observed in arsenic(IV) hydroxide (As(OH)4) and HAsO; see Kläning, Ulrik K.; Bielski, Benon H. J.; Sehested, K. (1989). "Arsenic(IV). A pulse-radiolysis study". Inorganic Chemistry. 28 (14): 2717–24. doi:10.1021/ic00313a007.
  11. ^ Cverna, Fran (2002). ASM Ready Reference: Thermal properties of metals. ASM International. pp. 8–. ISBN 978-0-87170-768-0. pdf.
  12. ^ Lide, David R., ed. (2000). "Magnetic susceptibility of the elements and inorganic compounds". Handbook of Chemistry and Physics (PDF) (81 ed.). CRC press. ISBN 0849304814.
  13. ^ Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.
  14. ^ a b Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.