Phosphorus pentabromide

Crystal structure
General
Surname	Phosphorus pentabromide
other names	Phosphorus (V) bromide
Ratio formula	PBr 5
Brief description	red-yellow solid
External identifiers / databases
CAS number 7789-69-7 EC number 232-186-6 ECHA InfoCard 100.029.260 PubChem 62678 Wikidata Q240557
properties
Molar mass	430.49 g mol −1
Physical state	firmly
density	3.57 g cm −3 (at −75 ° C)
solubility	reacts violently with water Decomposes in ethanol soluble in carbon disulfide and carbon tetrachloride
safety instructions
GHS labeling of hazardous substances danger H and P phrases H: 314 EUH: 014 P: 280-305 + 351 + 338-310
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Phosphorus is a chemical compound from the group of bromides .

Extraction and presentation

Phosphorus pentabromide can be obtained by reacting phosphorus (III) bromide with bromine .

properties

Phosphorus pentabromide

Phosphorus pentabromide is a red-yellow solid with a pungent odor, the crystals of which consist of PBr ₄ ⁺ Br ^- ions. It is extremely hygroscopic, heat and heat sensitive and has a corrosive effect. Above 35 ° C the compound decomposes to phosphorus (III) bromide and bromine. Some sources indicate complete decomposition between 84 and 106 ° C. Raman spectra of phosphorus pentabromide, condensed from the gas phase on a cold plate at 15 K, show neither bands that can be traced back to molecular phosphorus pentabromide, nor to the expected simple molecular dissociation products PBr ₃ + Br ₂ . Instead, the spectra can best be assigned to a mixture of PBr ₃ and PBr ₄ ⁺ Br ₃ ^- . At temperatures greater than 200 K, this solid turns into PBr ₄ ⁺ Br ^- .

In contrast to phosphorus pentachloride and phosphorus pentafluoride , it does not form bromine complexes PBr ₆ ^- with metal complexes , but is reduced to phosphorus (III) bromide and Br ^- .

With ammonium bromide it forms phosphorus nitride dibromide.

${\displaystyle \mathrm {PBr_{5}+NH_{4}Br\ {\xrightarrow[{{\ddot {U}}berschuss\ Br_{2}}]{NH_{4}Br}}\ {\frac {1}{n}}[NPBr_{2}]_{n}+4\ HBr} }$

It reacts with water to split off hydrogen bromide.

${\displaystyle \mathrm {PBr_{5}+4\ H_{2}O\longrightarrow H_{3}PO_{4}+5\ HBr} }$

The compound has an orthorhombic crystal structure with the space group Pbcm (space group no. 57) (a = 5.62, b = 16.91, c = 8.29 Å).

use

Phosphorus pentabromide can be used as a brominating agent.

Individual evidence

1. ↑ ^{a b c d e} A. F. Holleman , E. Wiberg , N. Wiberg : Textbook of Inorganic Chemistry . 102nd edition. Walter de Gruyter, Berlin 2007, ISBN 978-3-11-017770-1 , p. 781.
2. ^ Carl L. Yaws: Thermophysical Properties of Chemicals and Hydrocarbons . William Andrew, 2014, ISBN 978-0-323-29060-9 , pp. 361 ( books.google.de ).
3. ↑ data sheet phosphorus pentabromide from Sigma-Aldrich , accessed on February 17, 2011 ( PDF ).
4. ↑ ^{a b c d} Dale L. Perry: Handbook of Inorganic Compounds, Second Edition . CRC Press, 2016, ISBN 978-1-4398-1462-8 , pp. 312 ( limited preview in Google Book search).
5. ↑ ^{a b} Entry on phosphorus pentabromide in the GESTIS substance database of the IFA , accessed on July 23, 2016(JavaScript required) .
6. ^ H. Gerding, PC Nobel: The structure of solid phosphorus pentabromide. In: Recueil des Travaux Chimiques des Pays-Bas. 77, 1958, p. 472, doi : 10.1002 / recl.19580770513 .
7. ^ G. Davidson, EAV Ebsworth: Spectroscopic Properties of Inorganic and Organometallic Compounds . Royal Society of Chemistry, 1982, ISBN 978-0-85186-133-3 , pp. 187 ( limited preview in Google Book search).
8. ↑ James E. Huheey: Inorganic Chemistry. Walter de Gruyter, 2003, ISBN 978-3-110-17903-3 , p. 900 ( limited preview in Google book search).
9. ^ Christopher Talbot: Chemistry for the IB Diploma Second Edition . Hachette UK, 2015, ISBN 978-1-4718-2922-2 ( limited preview in Google Book Search).
10. ↑ M. van Driel, CH Mac Gillavry: The crystal structure of phosphorus pentabromide. In: Recueil des Travaux Chimiques des Pays-Bas. 62, 1943, p. 167, doi : 10.1002 / recl.19430620306 .
11. ^ W. Gabes, K. Olie: Refinement of the crystal structure of phosphorus pentabromide, PBr ₅ . In: Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry. 26, p. 443, doi : 10.1107 / S0567740870002595 .