Phosphoryl bromide

Phosphoryl bromide, also known as phosphorus oxybromide, is an inorganic compound with the formula POBr3.[3]

Phosphoryl bromide
Skeletal formula of phosphoryl bromide
Space-filling model of the phosphoryl bromide molecule
Names
Other names
Phosphorus oxybromide
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.029.252
EC Number
  • 232-177-7
UNII
UN number 1939 2576
  • InChI=1S/Br3OP/c1-5(2,3)4
    Key: UXCDUFKZSUBXGM-UHFFFAOYSA-N
  • InChI=1/Br3OP/c1-5(2,3)4
    Key: UXCDUFKZSUBXGM-UHFFFAOYAH
  • O=P(Br)(Br)Br
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
4
Tetrahedral at the P atom
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
Corrosive to tissue
GHS labelling:
GHS05: CorrosiveGHS07: Exclamation mark
Danger
H290, H314, H335
P234, P260, P261, 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
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

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.

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]

References

  1. https://pubchem.ncbi.nlm.nih.gov/compound/Phosphorus-oxybromide
  2. Templeton, Lieselotte K.; Templeton, David H. (1971). "The crystal structure of POBr3: space group and refinement by least squares". Acta Crystallogr. B. 27 (8): 1678–1679. doi:10.1107/S0567740871004564. S2CID 97905269.
  3. Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. pp. 501–503. ISBN 978-0-08-037941-8.
  4. Hönigschmid, O.; Hirschbold‐Wittner, F. (1940). "Das Atomgewicht des Phosphors. Analyse des Phosphoroxybromids". Zeitschrift für anorganische und allgemeine Chemie (in German). 243 (4): 355–360. doi:10.1002/zaac.19402430406. ISSN 1521-3749.
  5. Booth, Harold S.; Seegmiller, C. G.; Baker, Philip S.; Wexler, Sol; Johnson, Roy D. (2007-01-05), Fernelius, W. Conard (ed.), "Phosphorus(V) Oxybromide: (Phosphoryl Tribromide)", Inorganic Syntheses, Hoboken, NJ, USA: John Wiley & Sons, Inc., pp. 151–152, doi:10.1002/9780470132333.ch44, ISBN 978-0-470-13233-3, retrieved 2020-09-30
  6. Perry, Dale L. (2011). Handbook of Inorganic Compounds (2nd ed.). Boca Raton: Taylor & Francis. p. 310. ISBN 978-1-4398-1461-1. OCLC 587104373.
  7. Okuda, Tsutomu.; Hosokawa, Kazuto.; Yamada, Koji.; Furukawa, Yoshihiro.; Negita, Hisao. (1975). "Structural study of phosphoryl bromide by means of nuclear quadrupole resonance". Inorganic Chemistry. 14 (5): 1207–1209. doi:10.1021/ic50147a048. ISSN 0020-1669.
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