Fig. 6

Tetrahedral rotations in HT-AlPO4. Illustration of rotational axes of AlO4 and PO4 tetrahedra under tensile strain in the [001] direction. In a the rotational axis of the AlO4 tetrahedra is depicted as viewed from the [100] direction whereas b shows the rotational axis of the PO4 tetrahedra as viewed from the [010] direction