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Triphenylphosphine dichloride
Structural formula
Ball-and-stick model Space-filling model
CAS number 2526-64-9
Molecular formula C18H15Cl2P
Molar mass 333.19 g/mol
Melting point 176 °C[1], 85-100 °C[2]
Related compounds
Related compounds Phosphoranes
Phosphorus trichloride
Phosphorus pentachloride
Phosphorus halides
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references

Maintenance categories
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Triphenylphosphine dichloride, Ph3PCl2, is a chlorinating agent widely used in organic chemistry. Applications include the conversion of alcohols and ethers to alkyl chlorides, the cleavage of epoxides to vicinal dichlorides and the chlorination of carboxylic acids to acyl chlorides.[2]


Triphenylphosphine dichloride is usually prepared fresh by the addition of chlorine to triphenylphosphine.

Ph3P + Cl2 → Ph3PCl2

Both reagents are typically used in solution to ensure the correct stoichiometry.[2]

Alternatively, Ph3PCl2 can be obtained by chlorination of triphenylphosphine oxide with, for example, phosphorus trichloride, as in Grignard's original 1931 synthesis.[1]


In polar solvents such as acetonitrile or dichloromethane solutions, Ph3PCl2 adopts an ionic structure[3], [Ph3PCl]Cl, whereas in non-polar solvents like diethyl ether it exists as a non-solvated trigonal bipyramidal molecule.[4].


  1. ^ a b V. Grignard, J. Savard (1931). Compt. rend. 192: 592–5. 
  2. ^ a b c e-EROS Encyclopedia of Reagents for Organic Synthesis, doi:10.1002/047084289X.rt371
  3. ^ S. M. Godfrey, C. A. McAuliffe, R. G. Pritchard, J. M. Sheffield (1996). Chem. Commun.: 2521−2522. doi:10.1039/CC9960002521. 
  4. ^ S. M. Godfrey, C. A. McAuliffe, J. M. Sheffield (1998). Chem. Commun.: 921−922. doi:10.1039/a800820e.