Materials Data on Ba2Ca(PO4)4 by Materials Project
Ba2Ca(PO4)4 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Ba is bonded in a 9-coordinate geometry to nine O atoms. There are a spread of Ba–O bond distances ranging from 2.76–3.29 Å. Ca is bonded to six O atoms to form CaO6 octahedra that share corners with six PO4 tetrahedra. There are four shorter (2.31 Å) and two longer (2.43 Å) Ca–O bond lengths. There are two inequivalent P sites. In the first P site, P is bonded to four O atoms to form PO4 tetrahedra that share a cornercorner with one CaO6 octahedra. The corner-sharing octahedral tilt angles are 48°. There is three shorter (1.54 Å) and one longer (1.56 Å) P–O bond length. In the second P site, P is bonded to four O atoms to form PO4 tetrahedra that share corners with two equivalent CaO6 octahedra. The corner-sharing octahedra tilt angles range from 27–29°. There are a spread of P–O bond distances ranging from 1.53–1.56 Å. There are eight inequivalent O sites. In the first O site, O is bonded in a distorted bent 150 degrees geometry to one Ba, one Ca, and one P atom. In the second O site, O is bonded in a 3-coordinate geometry to one Ba, one Ca, and one P atom. In the third O site, O is bonded in a distorted bent 150 degrees geometry to one Ba, one Ca, and one P atom. In the fourth O site, O is bonded in a distorted bent 150 degrees geometry to one Ba and one P atom. In the fifth O site, O is bonded in a distorted single-bond geometry to one Ba and one P atom. In the sixth O site, O is bonded in a distorted single-bond geometry to one Ba and one P atom. In the seventh O site, O is bonded in a distorted single-bond geometry to one Ba and one P atom. In the eighth O site, O is bonded in a distorted single-bond geometry to two equivalent Ba and one P atom.