SrAl3(PO7)2 crystallizes in the trigonal R-3m space group. Sr(1) is bonded to six equivalent O(2) and six equivalent O(3) atoms to form SrO12 cuboctahedra that share corners with six equivalent P(1)O4 tetrahedra and faces with six equivalent Al(1)O6 octahedra. Al(1) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form AlO6 octahedra that share corners with four equivalent Al(1)O6 octahedra, corners with two equivalent P(1)O4 tetrahedra, and faces with two equivalent Sr(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 38°. P(1) is bonded to one O(1) and three equivalent O(2) atoms to form PO4 tetrahedra that share corners with three equivalent Sr(1)O12 cuboctahedra and corners with three equivalent Al(1)O6 octahedra. The corner-sharing octahedral tilt angles are 53°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a single-bond geometry to one P(1) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to one Sr(1), one Al(1), and one P(1) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Sr(1) and two equivalent Al(1) atoms.
SrAl3(PO7)2 crystallizes in the trigonal R-3m space group. Sr(1) is bonded to six equivalent O(2) and six equivalent O(3) atoms to form SrO12 cuboctahedra that share corners with six equivalent P(1)O4 tetrahedra and faces with six equivalent Al(1)O6 octahedra. All Sr(1)-O(2) bond lengths are 2.76 Å. All Sr(1)-O(3) bond lengths are 2.74 Å. Al(1) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form AlO6 octahedra that share corners with four equivalent Al(1)O6 octahedra, corners with two equivalent P(1)O4 tetrahedra, and faces with two equivalent Sr(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 38°. Both Al(1)-O(2) bond lengths are 1.99 Å. All Al(1)-O(3) bond lengths are 1.85 Å. P(1) is bonded to one O(1) and three equivalent O(2) atoms to form PO4 tetrahedra that share corners with three equivalent Sr(1)O12 cuboctahedra and corners with three equivalent Al(1)O6 octahedra. The corner-sharing octahedral tilt angles are 53°. The P(1)-O(1) bond length is 1.54 Å. All P(1)-O(2) bond lengths are 1.56 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a single-bond geometry to one P(1) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to one Sr(1), one Al(1), and one P(1) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Sr(1) and two equivalent Al(1) atoms.