Trimethylphosphine oxide

Trimethylphosphine oxide is an organophosphorus compound with the chemical formula . It forms highly hygroscopic, white, needle-shaped crystals. It forms a dihydrate .

Synthesis

Trimethylphosphine oxide can be obtained by reaction between phosphoryl chloride and a Grignard reagent methylmagnesium chloride.

Trimethylphosphine is easily oxidized by oxygen to trimethylphosphine oxide.

Structure

Trimethylphosphine oxide molecule is tetrahedral at the phosphorus atom. It is a resonance between these two structures:

The distances between atoms are as follows:

• C-H 110 pm
• P-C 181 pm
• P-O 148 pm

The angles between atoms are as follows:

• ∠C-P-O 112.3°
• ∠C-P-C 106.0°
• ∠P-C-H 109°

References