Overlap and Bonding Power of 2s,2p-Hybrid Orbitals

Abstract

A classification and nomenclature for 2s−2p hybrid AO's (atomic orbitals) of any degree of hybridization is proposed, and the concepts of cohybrids, antihybrids, and orthohybrids are defined. Overlap integrals S as follows are computed and tabulated as a function of the hybridization coefficient and the interatomic‐distance parameter for the case of two like first‐row atoms: S(h_β, h_β; ρ), S(h_β, h_oβ; ρ), and S(1s, h_β; ρ). (See also Figs. 1 and 2.) Here h_β denotes any 2s−2p hybrid, and h_oβ the corresponding orthohybrid. Slater AO's were used, and also, for selected ρ values for the case of C–C bonds, SCF AO's. In connection with this work, and extending fragmentary tables given in a previous paper, complete tables from ρ=3 to ρ=14, for the case of two like atoms, are given for the overlap integrals S(1s, 2s), S(2s, 2s), S(1s, 2pσ), S(2s, 2pσ), S(2pσ, 2pσ), and S(2pπ, 2pπ) using orthogonalized Slater 2s AO's, and carbon SCF 2pσ and 2pπ AO's. Tables of Slater‐AO overlap integrals S(1s, hβ) are given as a function of β for the radicals FH, OH, NH, and CH at their equilibrium distances, also similar tables based on SCF AO's for the case of C–H bonds of lengths 1.12, 1.09, and 1.06A. (See also Fig. 3.) The various tables and figures show that ``a little hybridization goes a long way''; that is to say, a small amount of s character in a pσ AO, or of pσ character in an s AO, causes a large change in S. Applications of this fact to problems of chemical binding are briefly suggested. These will be developed in a following paper. (Also see Note added in proof at end of this paper.)