|Preferred IUPAC name
3D model (JSmol)
CompTox Dashboard (EPA)
|Molar mass||569.57 g/mol|
|Appearance||Orange crystalline solid|
|Melting point||125.5 °C (257.9 °F; 398.6 K)|
|R-phrases (outdated)||R14, R34, R37|
Related Binary Phosphorus halides
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
|what is ?)(|
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.
The compound adopts a centrosymmetric structure with a P-P bond of 2.230 Å.
Diphosphorus tetraiodide reacts with bromine to form mixtures PI3-xBrx. With sulfur, it is oxidized to P2S2I4, retaining the P-P bond. It reacts with elemental phosphorus and water to make phosphonium iodide, which is collected via sublimation at 80 °C.
Diphosphorus tetraiodide is used in organic synthesis mainly as a deoxygenating agent. 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 and to convert ?,?-unsaturated carboxylic acids to ?,?-unsaturated bromides.