SrTi4(PO4)6 crystallizes in the trigonal R-3 space group. Sr(1) is bonded in a distorted hexagonal planar geometry to six equivalent O(2) atoms. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to three equivalent O(1) and three equivalent O(4) atoms to form TiO6 octahedra that share corners with six equivalent P(1)O4 tetrahedra. In the second Ti site, Ti(2) is bonded to three equivalent O(2) and three equivalent O(3) atoms to form TiO6 octahedra that share corners with six equivalent P(1)O4 tetrahedra. P(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form PO4 tetrahedra that share corners with two equivalent Ti(1)O6 octahedra and corners with two equivalent Ti(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 26-36°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Ti(1) and one P(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Sr(1), one Ti(2), and one P(1) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Ti(2) and one P(1) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Ti(1) and one P(1) atom.
SrTi4(PO4)6 crystallizes in the trigonal R-3 space group. Sr(1) is bonded in a distorted hexagonal planar geometry to six equivalent O(2) atoms. All Sr(1)-O(2) bond lengths are 2.57 Å. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to three equivalent O(1) and three equivalent O(4) atoms to form TiO6 octahedra that share corners with six equivalent P(1)O4 tetrahedra. All Ti(1)-O(1) bond lengths are 1.92 Å. All Ti(1)-O(4) bond lengths are 2.01 Å. In the second Ti site, Ti(2) is bonded to three equivalent O(2) and three equivalent O(3) atoms to form TiO6 octahedra that share corners with six equivalent P(1)O4 tetrahedra. All Ti(2)-O(2) bond lengths are 2.04 Å. All Ti(2)-O(3) bond lengths are 1.89 Å. P(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form PO4 tetrahedra that share corners with two equivalent Ti(1)O6 octahedra and corners with two equivalent Ti(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 26-36°. The P(1)-O(1) bond length is 1.54 Å. The P(1)-O(2) bond length is 1.55 Å. The P(1)-O(3) bond length is 1.55 Å. The P(1)-O(4) bond length is 1.54 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Ti(1) and one P(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Sr(1), one Ti(2), and one P(1) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Ti(2) and one P(1) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Ti(1) and one P(1) atom.