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]

References

1. Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
2. Zhengtao Xu "Recent Developments in Binary Halogen–Chalcogen Compounds, Polyanions and Polycations" in Handbook of Chalcogen Chemistry: New Perspectives in Sulfur, Selenium and Tellurium, Francesco Devillanova, Editor, 2006, RSC. pp. 381-416. Royal Society doi:10.1039/9781847557575-00455