 Phosphorus in orange, oxygen in red | |
 | |
| Names | |
|---|---|
| IUPAC names Tetraphosphorus hexaoxide Tricyclo[3.3.1.13,7]tetraphosphoxane | |
| Systematic IUPAC name 2,4,6,8,9,10-Hexaoxa-1,3,5,7-tetraphosphatricyclo[3.3.1.13,7]decane | |
| Other names | |
| Identifiers | |
3D model (JSmol) | |
| ChEBI | |
| ChemSpider |
|
| ECHA InfoCard | 100.032.414 |
| EC Number |
|
| 26856 | |
| UNII | |
| |
| |
| Properties | |
| P4O6 | |
| Molar mass | 219.88 g mol−1 |
| Appearance | colourless monoclinic crystals or liquid |
| Density | 2.135 g/cm3 |
| Melting point | 23.8 °C (74.8 °F; 296.9 K) |
| Boiling point | 173.1 °C (343.6 °F; 446.2 K) |
| reacts | |
| Acidity (pKa) | 9.4 |
| Structure | |
| See Text | |
| 0 | |
| Hazards | |
| GHS labelling: | |
 | |
| Danger | |
| NFPA 704 (fire diamond) | |
| Related compounds | |
Otheranions | Phosphorus trisulfide |
Othercations | Dinitrogen trioxide Arsenic trioxide Antimony trioxide |
Related compounds | Phosphorus pentoxide Phosphorous acid |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Phosphorus trioxide is thechemical compound with the molecular formula P4O6. Although the molecular formula suggests the name tetraphosphorus hexoxide, the name phosphorus trioxide preceded the knowledge of the compound's molecular structure, and its usage continues today. This colorless solid is structurally related toadamantane. It is formally theanhydride ofphosphorous acid, H3PO3, but cannot be obtained by the dehydration of the acid. A white solid that melts at room temperature, it is waxy, crystalline and highly toxic, with garlic odor.[1]
It is obtained by the combustion of phosphorus in a limited supply of air at low temperatures.
By-products include red phosphorus suboxide.[1]
Phosphorus trioxide reacts with water to formphosphorous acid, reflecting the fact that it is the anhydride of that acid.[2]
It reacts withhydrogen chloride to formH3PO3 andphosphorus trichloride.
With chlorine or bromine it forms the correspondingphosphoryl halide, and it reacts with iodine in a sealed tube to formdiphosphorus tetraiodide.[1]
P4O6 reacts withozone at 195 K to give the unstable compound P4O18.[3]
P4O18 decomposes above 238 K in solution with the release of O2 gas. Decomposition of dry P4O18 is explosive.
In adisproportionation reaction, P4O6 is converted into the mixed P(III)P(V) species P4O8 when heated in a sealed tube at 710 K, with the side product being red phosphorus.[3]
P4O6 is a ligand for transition metals, comparable tophosphite. An illustrative complex is P4O6·Fe(CO)4.[4] WithBH3, a dimeric adduct is produced:[3]
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