Cacodyl oxide

Cacodyl oxide is a chemical compound of the formula [(CH3)2As]2O. This organoarsenic compound is primarily of historical significance since it is sometimes considered to be the first organometallic compound synthesized in relatively pure form.[1][2]

Cacodyl oxide
Ball-and-stick model of cacodyl oxide
Line structure model of cacodyl oxide
Preferred IUPAC name
Dimethylarsinous anhydride
Other names
3D model (JSmol)
  • InChI=1S/C4H12As2O/c1-5(2)7-6(3)4/h1-4H3 ☒N
  • InChI=1/C4H12As2O/c1-5(2)7-6(3)4/h1-4H3
  • C[As](C)O[As](C)C
Molar mass 255.98 g/mol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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"Cadet's fuming liquid", which is composed of cacodyl and cacodyl oxide, was originally synthesized by heating potassium acetate with arsenic trioxide. It has a disagreeable odor and is toxic.

The molecular structure of [Ph2As]2O (Ph = phenyl), the tetraphenyl analogue of cacodyl oxide, has been established by X-ray crystallography.[3]

See alsoEdit


  1. ^ Elschenbroich, C. (2006). Organometallics. Weinheim: Wiley-VCH. ISBN 9783527293902.
  2. ^ Seyferth, D. (2001). "Cadet's Fuming Arsenical Liquid and the Cacodyl Compounds of Bunsen". Organometallics. 20 (8): 1488–1498. doi:10.1021/om0101947.
  3. ^ Doerrer, Linda H.; Green, Jennifer C.; Green, Malcolm L. H.; Haiduc, Ionel; Jardine, Christian N.; Pascu, Sofia I.; Silaghi-Dumitrescu, Luminita; Watkin, David J. (2000). "Group 6 transition metal carbonyl complexes with chalcogen-bridged diarsenic(III) ligands". Journal of the Chemical Society, Dalton Transactions (19): 3347–3355. doi:10.1039/b005269h.