fig1
Figure 1. Crystal-structure units of Nb4W7O31: (A) Structure A with a TTB type, (B) Structure B with another TTB type, and (C) Structure C with a confined ReO3 type. (D) Rietveld-refined XRD pattern of Nb4W7O31. The peaks of WO3 at 23.8, 24.5, and 33.8° are removed during the refinement. For clarity, not all peaks of Nb4W7O31 are indexed.
