The structural phase transition in SrV(6)O(11).

Single-crystal X-ray diffraction and specific heat studies establish that strontium hexavanadium undecaoxide, SrV(6)O(11), undergoes a P6(3)/mmc to inversion twinned P6(3)mc structural transition as the temperature is lowered through 322 K. The P6(3)/mmc and P6(3)mc structures have been determined at 353 K and at room temperature, respectively. For the room-temperature structure, seven of the ten unique atoms lie on special positions, and for the 353 K structure all of the seven unique atoms sit on special positions. The P6(3)/mmc to P6(3)mc structural phase transition, accompanied by a magnetic transition, is a common characteristic of AV(6)O(11) compounds, independent of the identity of the A cations.