Subhalide

In chemistry, subhalide usually refers to inorganic compounds that have a low ratio of halide to metal, made possible by metal–metal bonding (or element–element bonding for nonmetals), sometimes extensive. Many compounds meet this definition.^{[citation needed]}

P₂I₄ is a subiodide of phosphorus.

Examples

The normal halide of boron is BF₃. Boron forms many subhalides: several B₂X₄, including B₂F₄; also BF. Aluminium forms a variety of subhalides. For gallium, adducts of Ga₂Cl₄ are known. Phosphorus subhalides include P₂I₄, P₄Cl₂, and P₇Cl₃ (structurally related to [P₇]³⁻). For bismuth, the compound originally described as bismuth monochloride was later shown to consist of [Bi₉]⁵⁺ clusters and chloride anions.^[1] There are many tellurium subhalides, including Te₃Cl₂, Te₂X (X = Cl, Br, I), and two forms of TeI.^[2]