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Valence‐bond studies of four‐electron three‐center bonding units. II. FNO, HNO, LiNO, LiON, and HF 2 −

1979; Wiley; Volume: 16; Issue: 5 Linguagem: Inglês

10.1002/qua.560160509

1097-461X

Richard D. Harcourt, Walter Roso,

Crystallography and molecular interactions

Abstract For each of HNO, FNO, LiNO, LiON and HF 2 − , ab initio valence‐bond wave functions are reported for the four‐electron three‐center bonding unit which involves one of the following sets of atomic orbitals: (a) N X σ‐bond ( X = H, For Li) and oxygen 2 p π′; (b) LiO σ‐bond and nitrogen 2 p π′; (c) hydrogen 1 s and fluorine 2 p σ. Six S = 0 valence‐bond structures pertain for this type of bonding unit. For HF 2 − and FNO, the calculated bond‐eigenfunction coefficients for some of these valence‐bond structures differ appreciably according to whether the Slater determinants include only the electrons of the four‐electron three‐center bonding unit, or all of the valence‐shell ± inner‐shell electrons. For HNO, LiNO, and LiON, the all‐electron and all valence‐shell electron calculations generate similar sets of bond‐eigenfunction coefficients. For each of the nitrosyl systems, the bond‐eigenfunction coefficient with largest magnitude is calculated to be that for which zero atomic formal charges occur in the valence‐bond structure. Qualitative valence‐bond and “increased‐valence” descriptions of the bonding are presented.