Phosphoryl bromide
{{Chembox
| ImageFileL1 = Phosphoryl bromide.svg
| ImageSizeL1 = 120px
| ImageAltL1 = Skeletal formula of phosphoryl bromide
| ImageFileR1 = Phosphoryl bromide molecule spacefill.png
| ImageSizeR1 = 130
| ImageAltR1 = Space-filling model of the phosphoryl bromide molecule
| OtherNames = Phosphorus oxybromide
|Section1={{Chembox Identifiers
| CASNo = 7789-59-5
| CASNo_Ref = {{cascite|correct|CAS}}
| EC_number = 232-177-7
| UNNumber = 1939 2576
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = H98H8Y87QQ
| PubChem = 24613
| ChemSpiderID = 23015
| SMILES = O=P(Br)(Br)Br
| InChI = 1/Br3OP/c1-5(2,3)4
| InChIKey = UXCDUFKZSUBXGM-UHFFFAOYAH
| StdInChI = 1S/Br3OP/c1-5(2,3)4
| StdInChIKey = UXCDUFKZSUBXGM-UHFFFAOYSA-N
}}
|Section2={{Chembox Properties
| Formula = {{chem2|POBr3}}
| P=1|O=1|Br=3
| Appearance = Colorless crystals or thin plates with a faint orange tint
| Odor = Pungenthttps://pubchem.ncbi.nlm.nih.gov/compound/Phosphorus-oxybromide
| MeltingPtC = 56
| BoilingPtC = 192
| Solubility = Reacts violently with water
| SolubleOther = Soluble in diethyl ether, benzene, chloroform, carbon disulfide, and concentrated sulfuric acid
}}
|Section3={{Chembox Structure
| Structure_ref = {{ cite journal | title = The crystal structure of POBr3: space group and refinement by least squares | first1 = Lieselotte K. | last1 = Templeton | first2 = David H. | last2 = Templeton | journal = Acta Crystallogr. B | year = 1971 | volume = 27 | issue = 8 | pages = 1678–1679 | doi = 10.1107/S0567740871004564 | s2cid = 97905269}}
| MolShape = Tetrahedral at the P atom
| SpaceGroup = Pnma, No. 62
| UnitCellFormulas = 4
| LattConst_a = 9.467 Å
| LattConst_b = 9.938 Å
| LattConst_c = 6.192 Å
}}
|Section7={{Chembox Hazards
| MainHazards = Corrosive to tissue
| GHSPictograms = {{GHS05}}{{GHS07}}
| GHSSignalWord = Danger
| HPhrases = {{H-phrases|290|314|335}}
| PPhrases = {{P-phrases|234|260|261|264|271|280|301+330+331|303+361+353|304+340|305+351+338|310|312|321|363|390|403+233|404|405|501}}
}}
|Section8={{Chembox Related
| OtherCompounds = {{ubl|Phosphorus tribromide|Thiophosphoryl bromide|Phosphoryl fluoride|Phosphoryl chloride}}
}}
}}
Phosphoryl bromide, also known as phosphorus oxybromide, is an inorganic compound with the formula {{chem2|POBr3|auto=1}}.{{Greenwood&Earnshaw2nd|pages=501–503}}
Preparation
Phosphoryl bromide is prepared by the reaction between phosphorus pentabromide and phosphorus pentoxide:{{Cite journal|last1=Hönigschmid|first1=O.|last2=Hirschbold‐Wittner|first2=F.|date=1940|title=Das Atomgewicht des Phosphors. Analyse des Phosphoroxybromids|url=https://onlinelibrary.wiley.com/doi/abs/10.1002/zaac.19402430406|journal=Zeitschrift für anorganische und allgemeine Chemie|language=de|volume=243|issue=4|pages=355–360|doi=10.1002/zaac.19402430406|issn=1521-3749|url-access=subscription}}{{Citation|last1=Booth|first1=Harold S.|title=Phosphorus(V) Oxybromide: (Phosphoryl Tribromide)|date=2007-01-05|url=http://doi.wiley.com/10.1002/9780470132333.ch44|work=Inorganic Syntheses|pages=151–152|editor-last=Fernelius|editor-first=W. Conard|place=Hoboken, NJ, USA|publisher=John Wiley & Sons, Inc.|doi=10.1002/9780470132333.ch44|isbn=978-0-470-13233-3|access-date=2020-09-30|last2=Seegmiller|first2=C. G.|last3=Baker|first3=Philip S.|last4=Wexler|first4=Sol|last5=Johnson|first5=Roy D.|url-access=subscription}}
:{{chem2|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|date=September 2020}}
Structure and properties
Phosphoryl bromide forms colorless crystals or thin plates with a faint orange tint.{{Cite book|last=Perry|first=Dale L.|title=Handbook of Inorganic Compounds|publisher=Taylor & Francis|year=2011|isbn=978-1-4398-1461-1|edition=2nd|location=Boca Raton|pages=310|oclc=587104373}} Its crystals belong to the orthorhombic space group Pnma,{{Cite journal|last1=Okuda|first1=Tsutomu.|last2=Hosokawa|first2=Kazuto.|last3=Yamada|first3=Koji.|last4=Furukawa|first4=Yoshihiro.|last5=Negita|first5=Hisao.|date=1975|title=Structural study of phosphoryl bromide by means of nuclear quadrupole resonance|url=https://pubs.acs.org/doi/abs/10.1021/ic50147a048|journal=Inorganic Chemistry|language=en|volume=14|issue=5|pages=1207–1209|doi=10.1021/ic50147a048|issn=0020-1669|url-access=subscription}} 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.
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.