Increased-Valence or Electronic Hypervalence for a Diatomic One-Electron Bond

Richard D. Harcourt

doi:10.1071/CH05180

RESEARCH ARTICLE

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Increased-Valence or Electronic Hypervalence for a Diatomic One-Electron Bond

Richard D. Harcourt ^A

+ Author Affiliations

- Author Affiliations

^A School of Chemistry, University of Melbourne, Melbourne VIC 3010, Australia. Email: r.harcourt@unimelb.edu.au

Australian Journal of Chemistry 58(10) 753-755 https://doi.org/10.1071/CH05180
Submitted: 1 August 2005 Accepted: 13 September 2005 Published: 8 November 2005

Abstract

With a and b as overlapping atomic orbitals to form the A–B bonding molecular orbital ψ_ab = a + kb, it is deduced that for k ≠ 0, 1, or ∞, either the A atom or the B atom in the one-electron bond valence bond structure (A · B) exhibits increased-valence or electronic hypervalence, namely its valence exceeds unity. The result is illustrated using the results of STO-6G valence bond calculations for the one-electron bond of LiH⁺ and an excited state for H₂CN. Valencies for the ground-states of H₂⁺, H₂, and H₂⁻ are also considered.

Acknowledgments

I thank Dr Walter Roso for his ab initio VB program, Drs Frances Skrezenek and Harry Quiney for VB program installations, and Dr Jonathan White for providing a work station on which the STO-6G VB calculations were performed.

References

^* The atomic formal charges have not been indicated in VB structures 1–3 and 8–11. The V_a and V_A of the present paper correspond to the V_ay and V_a of ref. [1] which includes a third atomic centre Y with an additional electron.

^† For example, those of ref. [9], in which R_e = 4.321 a.u. Eight more recent estimates for R_e range between 4.08 and 4.15 a.u.^[¹⁰^]

Increased-Valence or Electronic Hypervalence for a Diatomic One-Electron Bond

Abstract

Acknowledgments

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