Room-temperature superstructure of ZrV2O7

The structure of ZrV2O7, zirconium pyrovanadate, has been refined from single-crystal synchrotron X-ray data. As with other phases in the AM(2)O(7) family, ZrV2O7 shows a set of strong reflections, which can be explained on the basis of a cubic unit cell with a = 8.765 Angstrom, and a family of much weaker reflections due to a 3 x 3 x 3 superstructure. The superstructure has been refined to R-F = 0.036 (a = 26.296 Angstrom, Pa (3) over bar, 6972 reflections) and contains highly regular ZrO6 and VO4 polyhedra. Of the six unique V2O7 groups, two are constrained by symmetry to contain linear V-O-V linkages, while the remaining four are free to bend away from 180 degrees. The structural distortions from the ideal high-symmetry structure to the observed room-temperature structure are described.