Some incorrect space groups in Inorganic Chemistry, Volume 16

Abstract

It is the purpose of this paper to point out that seven crystal structure analyses published in Volume 16 of Inorganic Chemistry (1977) were almost certainly described in space groups of unnecessarily low symmetry. In two instances the decrease in symmetry resulted in a change of Laue symmetry (from 2/m to 1); since in such cases there is no inherent problem in refinement, the reported molecular geometries are essentially correct, and our reformulations in the higher symmetry result in only minor adjustments. In the remaining five instances, however, the decrease in symmetry involved removing a center of symmetry without changing the Laue group. In such instances, singularities or near-singularities in the least-squares matrices-sometimes noticed by the original authors-led to refinement problems and the resulting structures are in all instances unsatisfactory in some aspects. For four of these latter cases we have carried out successful least-squares refinements in the higher symmetry space groups and have arrived at structures with improved agreement indexes and no unsatisfactory features.