Diphosphorus tetraiodide
| Ball-and-stick model of the diphosphorus tetraiodide molecule | |
| Names | |
|---|---|
| IUPAC name
Diphosphorus tetraiodide
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| Preferred IUPAC name
Tetraiododiphosphane
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|
| Other names
Phosphorus(II) iodide
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| Identifiers | |
13455-00-0  |
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| Properties | |
| P2I4 | |
| Molar mass | 569.57 g/mol |
| Appearance | Orange crystalline solid |
| Melting point | 124 to 127 °C (255 to 261 °F; 397 to 400 K) |
| Boiling point | Decomposes |
| Decomposes | |
| Vapor pressure | {{{value}}} |
| Related compounds | |
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Other anions
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Diphosphorus tetrafluoride Diphosphorus tetrachloride Diphosphorus tetrabromide |
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Other cations
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diarsenic tetraiodide |
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Related Binary Phosphorus halides
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phosphorus triiodide |
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Related compounds
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diphosphane diphosphines |
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| Infobox references | |
Diphosphorus tetraiodide is an orange crystalline solid with the formula P2I4. It has been used as a reducing agent in organic chemistry. It is a rare example of a compound with phosphorus in the +2 oxidation state, and can be classified as a subhalide of phosphorus. It is the most stable of the diphosphorus tetrahalides.[1]
Contents
Synthesis and structure
Diphosphorus tetraiodide is easily generated by the disproportionation of phosphorus triiodide in dry ether:
- 2 PI3 → P2I4 + I2
It can also be obtained by treating phosphorus trichloride and potassium iodide in anhydrous conditions.[2]
The compound adopts a centrosymmetric structure with a P-P bond of 2.230 Å.[3]
Reactions
Inorganic chemistry
Diphosphorus tetraiodide reacts with bromine to form mixtures PI3-xBrx. With sulfur, it is oxidized to P2S2I4, retaining the P-P bond.[1]
Organic chemistry
Diphosphorus tetraiodide is used in organic synthesis mainly as a deoxygenating agent.[4] It is used for deprotecting acetals and ketals to aldehydes and ketones, and for converting epoxides into alkenes and aldoximes into nitriles. It can also cyclize 2-aminoalcohols to aziridines[5] and to convert α,β-unsaturated carboxylic acids to α,β-unsaturated bromides.[6]
As foreshadowed by the work of Bertholet in 1855,[4] diphosphorus tetraiodide is used in the Kuhn–Winterstein reaction, the conversion of glycols to alkenes.[7]
References
- ↑ 1.0 1.1 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Z. Žák, M. Černík "Diphosphorus tetraiodide at 120 K" Acta Crystallographica, Section C: Crystal Structure Communications 1996, vol. C52, pp. 290-1. doi:10.1107/S0108270195012510
- ↑ 4.0 4.1 Alain Krief, Vikas N. Telvekar "Diphosphorus Tetraiodide" Encyclopedia for Reagents in Organic Synthesis 2009. doi:10.1002/047084289X.rd448.pub2
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
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- ↑ Lua error in package.lua at line 80: module 'strict' not found.
