Structures, energies, and electronic structures as derived from integrated projected densities are presented from ab initio MO calculations of H3PO (1), H3PCH2(2), H2PO2- (3), OPH2CH2- (4), and H2P(CH2)2- (5). The results show that allylic conjugation is not important in 3, 4, and 5 and that the PO and PC bonds in these compounds are best represented as dipolar bonds with little double-bond character. Simple electrostatic considerations suffice to interpret many of the results obtained concerning structure and energy.