Phosphorus heptabromide

For the pigment code PBr7, see List of inorganic pigments § Brown pigments.
Phosphorus heptabromide
Skeletal formula of phosphorus heptabromide
Space-filling models of the ions in phosphorus heptabromide
Names
IUPAC name
Tetrabromophosphanium tribromide
Other names
  • Perbromophosphonium tribromide
  • Phosphorus heptabromide
  • Tetrabromophosphonium tribromide
Identifiers
3D model (JSmol)
  • InChI=1S/Br4P.Br3/c1-5(2,3)4;1-3-2/q+1;-1
    Key: QBFSXBUUGDHSFY-UHFFFAOYSA-N
  • Br[P+](Br)(Br)Br.Br[Br-]Br
Properties
PBr7
Molar mass 590.302 g·mol−1
Appearance Red prismatic crystals
Structure[1]
Orthorhombic
Pnma, No. 64
a = 9.35 Å, b = 7.94 Å, c = 14.69 Å
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Phosphorus heptabromide is an inorganic compound with the chemical formula PBr7. It is one of the phosphorus bromides. At normal conditions, it forms red prismatic crystals. PBr7 can be prepared by the sublimation of a mixture of phosphorus pentabromide and bromine.[2]

PBr5 + Br2 → PBr7

The structure of PBr7 consists of a tetrabromophosphonium cation [PBr4]+, paired with a tribromide anion [Br3]−, and the tribromide anion is non-symmetric.[1]

  1. ^ a b Breneman, G. L.; Willett, R. D. (1967). "The crystal structure of phosphorus heptabromide, PBr7". Acta Crystallographica. 23 (3): 467–471. doi:10.1107/S0365110X67002981.
  2. ^ T. E. (Thomas Edward) Thorpe. A dictionary of applied chemistry (Volume 4)