Organophosphines, like phosphine itself, are pyramidal molecules with approximate C symmetry. The C–P–C bond angles are approximately 98.6°. The C–P–C bond angles are consistent with the notion that phosphorus predominantly uses the 3p orbitals for forming bonds and that there is little sp hybridization of the phosphorus atom. The latter is a common feature of the chemistry of phosphorus. As a result, the lone pair of trimethylphosphine has predominantly s-character as is the case for phosphine, PH.
Tertiary phosphines are pyramidal. When the organic substituents all differ, the phosphine is chiral and configurationally stable (in contrast to NRR'R").  Complexes derived from the chiral phosphines can catalyse reactions to give chiral, enantioenriched products.