Electronic structure and bonding in crystalline peroxides

Markus Königstein, Alexei A. Sokol, and C. Richard A. Catlow
Phys. Rev. B 60, 4594 – Published 15 August 1999
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Abstract

Hartree-Fock and density-functional PW91 theories as realized in the CRYSTAL95 code have been applied to investigate the structural and electronic properties of Ba, Sr, and Ca peroxide materials with the calcium carbide crystal structure, results for which are compared with those for the corresponding oxides. Special attention is paid to the stabilization of the peroxide molecular ion O22 in the ionic environment provided by the lattice, and to chemical bonding effects. In order to describe the covalent bonding within the O22 ion and the polarization of the O ion in the crystal electrostatic field, it is essential to include an account of the effects of electron correlation. The PW91 density functional has allowed us to reproduce the crystallographic parameters within a 3% error. The chemical bonding within the peroxide molecular ion has a complex nature with a balance between the weak covalent bond of σz type and the strong electrostatic repulsion of the closed-shell electron groups occupying O2s and O2px and 2py states. Compression of the peroxide ion in the ionic crystals gives rise to an excessive overlap of the O2s closed shells of the two O ions of a peroxide molecular ion O22, which in turn determines the antibonding character of the interaction and chemical bonding in the O22 molecular ion.

  • Received 4 March 1998

DOI:https://doi.org/10.1103/PhysRevB.60.4594

©1999 American Physical Society

Authors & Affiliations

Markus Königstein, Alexei A. Sokol, and C. Richard A. Catlow

  • Davy Faraday Research Laboratory, The Royal Institution of Great Britain, 21 Albemarle Street, London W1X 4BS, United Kingdom

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Issue

Vol. 60, Iss. 7 — 15 August 1999

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