view article
Figure 5
Parts (a) and (b) show the two distinct planar long-range O/F ordered possibilities, assuming that an O atom is always opposite an F atom in each FeO3F3 pseudo-octahedron, along with the O/F ordering-induced Fe displacements [of magnitude 0.12–0.13 Å/(21/2) in (a) and (b), and of magnitude 0.12–0.13 Å in (c)]. Note that the [110] direction of rutile is horizontal in (a) and (b), while the [001] or c direction is vertical. Part (c) shows the possible O/F ordering patterns in nearest-neigbour clusters of four FeO3F3 octahedra, assuming that the right-hand octahedron has the same O/F ordering pattern in each case. The F ions for this octahedron are represented by small black balls, while the oxygen ions are represented by small circled white balls. The [110] direction is vertical while the [[{\overline 1}10]] direction is horizontal in (c).

IUCrJ
Volume 2| Part 1| January 2015| Pages 74-84
ISSN: 2052-2525
doi:10.1107/S2052252514022556