Reversible Dissociation of a Dialumene**

Abstract

Abstract Dialumenes are neutral Al I compounds with Al=Al multiple bonds. We report the isolation of an amidophosphine‐supported dialumene. Our X‐ray crystallographic, spectroscopic, and computational DFT analyses reveal a long and extreme trans‐bent Al=Al bond with a low dissociation energy and bond order. In solution, the dialumene can dissociate into monomeric Al I species. Reactivity studies reveal two modes of reaction: as dialumene or as aluminyl monomers.