Figure 1
(a) Crystal structure of (NH4)3TiF7 at T = 296 K. Three unique TiF6 octahedra, two unique NH4+ ions and one additional ion F− are marked. (b) Four different orientations of the slightly distorted (Ti3)F6 octahedron (colored figures) are obtained by the action of the fourfold axis while its pseudo threefold axis gyrates around the fourfold axis. |