An arsanylidene is an arsenic analogue of a carbene R-As: .

An azylene is a nitrene, an organic compound which is a univalent nitrogen equivalent of a carbene.

An arsinidene is an alternative name for an arsanylidene, the arsenic analogue of a carbene R-As: .

An arsinediyl is an alternative name for an arsanylidene, the arsenic analogue of a carbene R-As: .

It proceeds through a carbene intermediated mechanism.first an acyl carbene is formed, which undergoes wolff rearrangement followed by hydrolysis to yield carboxilic acid