Bonding in H₃AB compounds

The nature of binding in the 14 valence electron H₃AB molecules is examined, where A and B are taken from the second and third rows. The AB bonding is inferred from the computed structures, d orbital populations, and localized orbitals. Near Hartree–Fock results are reported for the strongest bonding compounds, which are those with third row atoms A, and second row atoms B. Phosphine oxide, and to a lesser extent phosphine sulfide, are found to be effectively doubly bound. Amine oxide and sulfide are found to be ionic complexes. The thiazyl bond is confirmed as triple in nature. The exotic compound F₃IC is proposed as a synthetic target.