P-Chiral phosphines are organophosphorus compounds of the formula PRR′R″, where R, R′, R″ = H, alkyl, aryl, etc.  They are a subset of chiral phosphines, a broader class of compounds where the stereogenic center can reside at sites other than phosphorus.  P-chirality exploits the high barrier for inversion of phosphines, which ensures that enantiomers of PRR'R" do not racemize readily.  The inversion barrier is relatively insensitive to substituents for triorganophosphines.  By contrast, most amines of the type NRR′R″ undergo rapid pyramidal inversion.