Caesium auride

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Caesium auride
3D model (JSmol)
Molar mass 329.872022 g·mol−1
Appearance Yellow crystals
Melting point 580 °C (1,076 °F; 853 K)[1]
reacts violently
body centered cubic
a = 4.24 Å[1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Caesium auride is the inorganic compound with the formula CsAu. It is the Cs+ salt of the unusual Au anion.[2]

Preparation and reactions[edit]

CsAu is obtained by heating a stoichiometric mixture of caesium and gold. The two metallic-yellow liquids react to give a transparent product. A solution of CsAu in liquid ammonia is brown, and the solid is yellow (the colour of both metals making up the compound). The ammonium adduct is dark blue. Despite being a compound of two metals, CsAu lacks metallic properties since it is a salt with localized charges.

The compound hydrolyzed readily, yielding caesium hydroxide, metallic gold, and hydrogen. Solutions in ammonia undergo metathesis with tetramethylammonium loaded ion exchange resin to give tetramethylammonium auride.[3]


  1. ^ a b Kienast, Gerhard; Verma, Jitendra; Klemm, Wilhelm (June 1961). "Das Verhalten der Alkalimetalle zu Kupfer, Silber und Gold". Zeitschrift für anorganische und allgemeine Chemie (in German). 310 (3): 143–169. doi:10.1002/zaac.19613100304.
  2. ^ Peer, William J.; Lagowski, J. J. (1978). "Metal-Ammonia Solutions. 11. Au, a Solvated Transition Metal Anion". J. Am. Chem. Soc. 100: 6260–6261. doi:10.1021/ja00487a064.
  3. ^ Jansen, Martin (2005-11-30). "Effects of relativistic motion of electrons on the chemistry of gold and platinum". Solid State Sciences. 7 (12): 1464–1474. doi:10.1016/j.solidstatesciences.2005.06.015.

Further reading[edit]

  • Jansen, Martin (2008). "The chemistry of gold as an anion". Chemical Society Reviews. 37 (9): 1826–1835. doi:10.1039/B708844M. PMID 18762832.—includes photograph of the compound.