DOI

10.1039/d5cp03656a

Abstract

The existence and nature of sigma hole type interactions in inorganic extended solids remain largely unexamined, even though the influence of such interactions for heteroorganic compounds is well known. The series of group 5 MOX3oxyhalides are intriguing in this regard since several of the known crystal structures are molecular solids with highly polarized M centers. We examine computationally the bonding in the isolated MOX3 molecules and their smallest clusters (MOX3)nwhere M = V, Nb, and Ta, and X = H, F, Cl, Br, and I. That investigation provides us with substantial evidence, based on patterns and quantitative trends exhibited in the bonding and energetics of the oxyhalide clusters, that several of the extended solids are stabilized by sigma-hole-supported M⋯O and more rarely M⋯X bonding interactions between the MOX3 molecules or dimers. In particular, one-dimensional stacks of doubly bridged, X2OMX2MOX2, dimer units in several of the oxyhalide crystal structures are shown to be propagations of sigma-hole-supported bonding interactions with weak charge transfer contributions that are already established at the level of the tetramer. Our results are in harmony with a more recent crystal structure for NbOCl3 over a much older proposal.

Document Type

Article

Publication Date

11-12-2025

Publisher Statement

© 2026 The Author(s). Published by the Royal Society of Chemistry on behalf of the Owner Societies   This article is licensed under a Creative Commons Attribution 4.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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