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Names | |
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IUPAC name
Phosphorus(V) iodide
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Other names
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Identifiers | |
CompTox Dashboard (EPA)
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Properties | |
PI5 | |
Molar mass | 665.49611 g·mol−1 |
Appearance | Brown-black crystalline solid (disputed)[1] |
Melting point | 41 °C (106 °F; 314 K) (disputed)[1] |
Related compounds | |
Related compounds
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Phosphorus pentaiodide is a hypothetical inorganic compound with formula PI5. The existence of this compound has been claimed intermittently since the early 1900s.[2] The claim is disputed: "The pentaiodide does not exist (except perhaps as PI3·I2, but certainly not as [PI4]+I−...)".[3]
Phosphorus pentaiodide was reported to be a brown-black crystalline solid melting at 41 °C produced by the reaction of lithium iodide and phosphorus pentachloride in methyl iodide, however, this claim is disputed and probably generated a mixture of phosphorus triiodide and iodine.[1][4]
Although phosphorus pentaiodide has been claimed to exist in the form of [PI4]+I− (tetraiodophosphonium iodide), experimental and theoretical data refutes this claim.[5][1]
Unlike the elusive PI5, the [PI4]+ cation (tetraiodophosphonium cation) is widely known. This cation is known with the anions tetraiodoaluminate [AlI4]−, hexafluoroarsenate [AsF6]−, hexafluoroantimonate [SbF6]− and tetraiodogallate [GaI4]−. [4][5]