view article
Figure 7
The local coordination of Nb1 and Nb2 in CaNb5+2(P4O13)(P2O7)O. (a) In this structure, the two crystallographically distinct Nb5+O6 octahedra do not have equal bonds 5/6 v.u. in strength. Instead, (b) non-local bond-topological asymmetry imposes bond-valence (and thus bond-length) variability within the polyhedra, which (c) serve as starting configurations for crystallographic effects to lead to the observed local geometries. The shaded spheres represent O2−.

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