The molecule features a pyramidal phosphorus(III) center bound to three ethoxide groups.

Its 31P NMR spectrum features a signal at around +139 ppm vs phosphoric acid standard.

Triethylphosphite is prepared by treating phosphorus trichloride with ethanol in the presence of a base, typically a tertiary amine:[1] In the absence of the base, the reaction of ethanol and phosphorus trichloride affords diethylphosphite ((EtO)2P(O)H).

[2] This approach can be utilized for carbonyl α-hydroxylation by reacting the enolate with oxygen, producing an α-hydroperoxide which can be reduced by triethyl phosphite to the alcohol.

[2] In coordination chemistry and homogeneous catalysis, triethylphosphite finds use as a soft ligand.