Subhalide

P₂I₄ is a subiodide of phosphorus.

In chemistry, subhalide usually refers to inorganic compounds where the halide/metal ratio requires metal-metal (or element-element for nonmetals) bonding, sometimes extensively. Many compounds meet this definition.

Examples

Boron forms many subhalides, starting with B₂X₄, a representative member being diboron tetrafluoride. Aluminium forms a variety of subhalides. For gallium, adducts of Ga₂Cl₄ are known. Phosphorus subhalides include P₂I₄ P₄Cl₂, and P₇Cl₃ (structurally related to P₇³⁻). For bismuth, the compound originally described as bismuth monochloride was later shown to consists of Bi₉⁵⁺ clusters with chloride anions.^[1]Telluriium subhalides are particularly extensive and include the following members 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 0080379419. 
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