BaSr2(PO4)2 crystallizes in the trigonal R-3m space group. Ba(1) is bonded to six equivalent O(1) and six equivalent O(2) atoms to form distorted BaO12 cuboctahedra that share edges with six equivalent Ba(1)O12 cuboctahedra and edges with six equivalent P(1)O4 tetrahedra. Sr(1) is bonded in a 10-coordinate geometry to one O(1) and nine equivalent O(2) atoms. P(1) is bonded to one O(1) and three equivalent O(2) atoms to form PO4 tetrahedra that share edges with three equivalent Ba(1)O12 cuboctahedra. There are two inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to three equivalent Ba(1), one Sr(1), and one P(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one Ba(1), three equivalent Sr(1), and one P(1) atom.
BaSr2(PO4)2 crystallizes in the trigonal R-3m space group. Ba(1) is bonded to six equivalent O(1) and six equivalent O(2) atoms to form distorted BaO12 cuboctahedra that share edges with six equivalent Ba(1)O12 cuboctahedra and edges with six equivalent P(1)O4 tetrahedra. All Ba(1)-O(1) bond lengths are 3.20 Å. All Ba(1)-O(2) bond lengths are 2.72 Å. Sr(1) is bonded in a 10-coordinate geometry to one O(1) and nine equivalent O(2) atoms. The Sr(1)-O(1) bond length is 2.54 Å. There are three shorter (2.78 Å) and six longer (2.80 Å) Sr(1)-O(2) bond lengths. P(1) is bonded to one O(1) and three equivalent O(2) atoms to form PO4 tetrahedra that share edges with three equivalent Ba(1)O12 cuboctahedra. The P(1)-O(1) bond length is 1.55 Å. All P(1)-O(2) bond lengths are 1.56 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to three equivalent Ba(1), one Sr(1), and one P(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one Ba(1), three equivalent Sr(1), and one P(1) atom.