Phosphonium

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Phosphonium
Ball and stick model of phosphonium
Identifiers
PubChem 5460504
ChemSpider 4574014 YesY
ChEBI CHEBI:30282
Gmelin Reference 292
Jmol-3D images Image 1
Properties
Molecular formula PH+
4
Molar mass 35.00552 g mol-1
Related compounds
Other cations Ammonium
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references

The phosphonium (more obscurely: phosphinium) cation describes polyatomic cations with the chemical formula PR+
4
.[2] Salts of the parent PH4+ are rarely encountered, but this ion is an intermediate in the preparation of the industrially useful tetrakis(hydroxymethyl)phosphonium chloride:

PH3 + HCl + 4 CH2O → P(CH2OH)4+Cl-

Organic phosphonium salts are common reagents in the laboratory. Those with a P-H bond are produced through protonation of phosphines:

PR3 + H+ → HPR3+

Many organic quaternary phosphonium cations (P+
R
4
) are produced by alkylation of organophosphines. For example the reaction of triphenylphosphine with methyl iodide gives methyltriphenylphosphonium iodide, the precursor to a Wittig reagent:

PPh3 + CH3I → CH3PPh3+I-

The cation tetraphenylphosphonium (PPh4+) is a useful precipitating agent, analogous to quaternary ammonium salts used in phase transfer catalysis.

See also[edit]

References[edit]

  1. ^ a b "phosphonium (CHEBI:30282)". Chemical Entities of Biological Interest (ChEBI). UK: European Bioinformatics Institute. 
  2. ^ D. E. C. Corbridge "Phosphorus: An Outline of its Chemistry, Biochemistry, and Technology" 5th Edition Elsevier: Amsterdam 1995. ISBN 0-444-89307-5.