Phosphoryl bromide
Chemical compound
From Wikipedia, the free encyclopedia
Phosphoryl bromide, also known as phosphorus oxybromide, is an inorganic compound with the formula POBr3.[3]
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| Names | |||
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| Other names
Phosphorus oxybromide | |||
| Identifiers | |||
3D model (JSmol) |
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| ChemSpider | |||
| ECHA InfoCard | 100.029.252 | ||
| EC Number |
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PubChem CID |
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| UNII | |||
| UN number | 1939 2576 | ||
CompTox Dashboard (EPA) |
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| Properties | |||
| POBr3 | |||
| Molar mass | 286.685 g·mol−1 | ||
| Appearance | Colorless crystals or thin plates with a faint orange tint | ||
| Odor | Pungent[1] | ||
| Density | 2.822 g/cm3[1] | ||
| Melting point | 56 °C (133 °F; 329 K) | ||
| Boiling point | 192 °C (378 °F; 465 K) | ||
| Reacts violently with water[1] | |||
| Solubility | Soluble in diethyl ether, benzene, chloroform, carbon disulfide, and concentrated sulfuric acid[1] | ||
| Structure[2] | |||
| Pnma, No. 62 | |||
a = 9.467 Å, b = 9.938 Å, c = 6.192 Å | |||
Formula units (Z) |
4 | ||
| Tetrahedral at the P atom | |||
| Hazards | |||
| Occupational safety and health (OHS/OSH): | |||
Main hazards |
Corrosive to tissue | ||
| GHS labelling: | |||
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| Danger | |||
| H290, H314, H335 | |||
| P234, P260, P264, P271, P280, P301+P330+P331, P303+P361+P353, P304+P340, P305+P351+P338, P310, P312, P321, P363, P390, P403+P233, P404, P405, P501 | |||
| 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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Preparation
Phosphoryl bromide is prepared by the reaction between phosphorus pentabromide and phosphorus pentoxide:[4][5]
- 3 PBr5 + P2O5 → 5 POBr3
It can also be prepared via the slow addition of liquid bromine to phosphorus tribromide at 0 °C, followed by the slow addition of water and vacuum distillation of the resulting slurry.[citation needed]
Structure and properties
Phosphoryl bromide forms colorless crystals or thin plates with a faint orange tint.[6] Its crystals belong to the orthorhombic space group Pnma,[2][7] with intermolecular Br–O bridges creating infinite chains within the structure. The intermolecular bonding causes distortions from the C3v symmetry found in the free molecule.[2]
It is stored in sealed glass ampoules.
Uses
Phosphoryl bromide finds use as a specialist brominating agent.
Safety
Phosphoryl bromide reacts violently with water evolving heat, forming phosphoric acid and hydrobromic acid. Reacts with organic compounds to cause fire. Evolves highly toxic and corrosive gases when exposed to fire. When heated to decomposition, it emits highly toxic fumes like bromides, oxybromides and oxides of phosphorus. It is corrosive to metals and tissues.[6][1]
