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Systematic name Trimethylphosphine
Other names trimethylphosphane
Molecular formula C3H9P
Molar mass 76.07 g/mol
Appearance Colorless liquid, Pyrophoric
CAS number [594-09-2]
Density and phase 0.735 g/cm3 liquid
Solubility in water low
Other solvents most organic solvents
Melting point -86 °C
Boiling point 38-39 °C
Trigonal pyramidal
Dipole moment 1.19 Debye
MSDS External MSDS
Main hazards toxic
NFPA 704
Flash point
R/S statement R: 11-36/37/38
S: 9-16-26-36/37/39
RTECS number
Supplementary data page
Structure and
n, εr, etc.
Phase behaviour
Solid, liquid, gas
Spectral data UV, IR, NMR, MS
Related compounds
Related compounds NMe3
Except where noted otherwise, data are given for
materials in their standard state (at 25 °C, 100 kPa)
Infobox disclaimer and references

Trimethylphosphine is the chemical compound with the formula P(CH3)3, commonly abbreviated PMe3. This colorless liquid has a strongly unpleasant odour, which characteristic of alkylphosphines. It is a pyramidal molecule with C3v symmetry, similar to ammonia (NH3) and phosphine (PH3). As a ligand, its cone angle is 118°.[1]

PMe3 is prepared using Grignard reagents:[2]

3 CH3MgBr + P(OC6H5)3 → P(CH3)3 + 3 MgBrOC6H5

The synthesis is conducted in a dibutyl ether, from which the more volatile PMe3 can be distilled.

Coordination chemistry

Trimethylphosphine is a highly basic ligand that forms complexes with most metals. The synthesis of an illustrative example is shown:

PMe3 + Fe(CO)5 → Fe(CO)4PMe3 + CO

Its complex with silver iodide, AgI(PMe3) is a weighable, air stable compound that releases PMe3 upon heating.


PMe3 is potentially pyrophoric, as well as toxic.


  1. ^ G. L. Miessler and D. A. Tarr “Inorganic Chemistry” 3rd Ed, Pearson/Prentice Hall publisher, ISBN 0-13-035471-6.
  2. ^ Leutkens, Jr., M. L.; Sattelberger, A. P.; Murray, H. H.; Basil, J. D.; Fackler, Jr., J. P. (1990). "Trimethylphosphine". Inorganic Syntheses 28: 305-310. doi:10.1002/9780470132593.ch76.
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Trimethylphosphine". A list of authors is available in Wikipedia.
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