Cyaarside

Cyaarside, also called cyarside, is the As≡C− anion. Featuring a triple bond between arsenic and carbon, it is the arsenic analogue of cyanide and cyaphide.

Preparation
An actinide cyaarside complex can be prepared by C−O bond cleavage of the arsaethynolate anion, the arsenic analogue of cyanate and phosphaethynolate. Reaction of the uranium complex [((^{Ad,Me}ArO)3N)U^{III}(DME)] with one molar equivalent of [ in the presence of 2.2.2-cryptand results in the formation of a dinuclear, oxo-bridged uranium complex featuring a C≡As ligand.