Cyaphide

It is not known as a discrete salt; however, in silico measurements reveal that the −1 charge in this ion is located mainly on carbon (0.65), as opposed to phosphorus.

The word "cyaphide" was first coined in 1992, by analogy with cyanide.

[2] More recent preparations use two other routes: Treatment of the η1-coordinated phosphaalkyne complex trans–[RuH(P≡CSiPh3)(dppe)2]+ with an alkoxide resulted in desilylation, followed by subsequent rearrangement to the corresponding carbon-bound cyaphide complex.

[4] An actinide cyaphide complex can be prepared by C−O bond cleavage of the phosphaethynolate anion, the phosphorus analogue of cyanate.

[5] Reaction of the uranium complex [((Ad,MeArO)3N)UIII(DME)] with [Na(OCP)(dioxane)2.5] in the presence of 2.2.2-cryptand results in the formation of a dinuclear, oxo-bridged uranium complex featuring a C≡P ligand.