Materials Data on BaSr2(PO4)2 by Materials Project
BaSr2(PO4)2 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Ba2+ is bonded to twelve O2- atoms to form distorted BaO12 cuboctahedra that share edges with six equivalent BaO12 cuboctahedra and edges with six equivalent PO4 tetrahedra. There are six shorter (2.72 Å) and six longer (3.20 Å) Ba–O bond lengths. Sr2+ is bonded in a 10-coordinate geometry to ten O2- atoms. There are a spread of Sr–O bond distances ranging from 2.54–2.80 Å. P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share edges with three equivalent BaO12 cuboctahedra. There is one shorter (1.55 Å) and three longer (1.56 Å) P–O bond length. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to three equivalent Ba2+, one Sr2+, and one P5+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to one Ba2+, three equivalent Sr2+, and one P5+ atom.