Gold(I) sulfide

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Gold(I) sulfide is the inorganic compound with the formula Au2S. It is the principal sulfide of gold. It decomposes to gold metal and elemental sulfur, illustrating the "nobility" of gold.

Gold(I) sulfide
Gold(I) sulfide unit cell
Names
IUPAC name
Gold(I) sulfide
Other names
Aurous sulfide
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.013.749 Edit this at Wikidata
EC Number
  • 215-123-7
UNII
  • InChI=1S/2Au.S/q2*+1;-2
    Key: YVIYNOINIIHOCG-UHFFFAOYSA-N
  • [S-2].[Au+].[Au+]
Properties
Au2S
Molar mass 425.998 g/mol
Density 11 g/cm3[1]
Melting point 240 °C (464 °F; 513 K)
Insoluble
Related compounds
Other anions
Copper(I) sulfide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Structure and preparation

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The compound crystallizes in the motif seen for cuprous oxide: gold is 2-coordinate, sulfur 4-coordinate, and the S-Au-S linkage is linear.[2] Linear coordination geometry is typical of gold(I) compounds, e.g. the coordination complex chloro(dimethyl sulfide)gold(I). The structure is similar to the α form of silver sulfide (argentite), which only exists at high temperatures.[3]

It can be prepared by treating gold chloride with hydrogen sulfide[4] It also arises by sulfiding dicyanoaurate:

H2S + 2 K[Au(CN)2] → Au2S + 2 KCN + 2 HCN

This product is described as "initially dark reddish-brown" solid that turns "steel-gray".[5][3]

References

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  1. ^ Perry, Dale, ed. (1995). Handbook of Inorganic Compounds. p. 184. ISBN 9780849386718.
  2. ^ Wells, A.F. (1984) Structural Inorganic Chemistry, Oxford: Clarendon Press. ISBN 0-19-855370-6.
  3. ^ a b Ishikawa, K. (1995). "Structure and Electrical Properties of Au2S". Solid State Ionics. 79: 60–66. doi:10.1016/0167-2738(95)00030-A.
  4. ^ N. N. Greenwood, A. Earnshaw, Chemistry of the Elements, 2nd ed., Butterworth-Heinemann, Oxford, UK, 1997.
  5. ^ Faltens, Marjorie O. (1970). "Mössbauer Spectroscopy of Gold Compounds". The Journal of Chemical Physics. 53 (11): 4249–4264. Bibcode:1970JChPh..53.4249F. doi:10.1063/1.1673931.