view article
Figure 5
Inherent bond-valence (and thus bond-length) variation resulting from the valence-sum rule for (a) different coordination numbers and (b) different oxidation states (OS) of next-nearest neighbours for a simple bond topology. Grey circles are anions. White circles are cations of the same oxidation state and coloured circles are cations of different oxidation states. The fragment shown is self-contained; wavy lines indicate further bonds which are inconsequential to x1 and x3. Black bonds are terminal and consequently equal to the oxidation state of the anion, `a'; from here, `b' and `c' are deduced, and x1 and x3 are shown to be necessarily unequal in strength, thus causing bond-length variation within the local coordination.

IUCrJ
Volume 7| Part 4| July 2020| Pages 581-629
ISSN: 2052-2525
https://doi.org/10.1107/S2052252520005928