Carbene-stabilized main group diatomic allotropes.

While transition metals are well known for assuming the formal oxidation state of zero in various compounds main group elements have rarely engaged in this practice. Recent reports of N-heterocyclic carbene-stabilized main group diatomic allotropes (i.e., Si(2), Ge(2), P(2), As(2)) denote a breakthrough of zero-oxidation state main group chemistry. This Perspective addresses the synthesis and characterization of these highly reactive main group molecules, with a particular emphasis on the very recent progress in the reactivity study of carbene-stabilized Si(2) and P(2).