Materials Data on BaCaP2O7 by Materials Project
BaCaP2O7 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are two inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a 8-coordinate geometry to eleven O2- atoms. There are a spread of Ba–O bond distances ranging from 2.76–3.41 Å. In the second Ba2+ site, Ba2+ is bonded in a 11-coordinate geometry to eleven O2- atoms. There are a spread of Ba–O bond distances ranging from 2.72–3.31 Å. There are two inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.34–2.75 Å. In the second Ca2+ site, Ca2+ is bonded to seven O2- atoms to form distorted CaO7 pentagonal bipyramids that share corners with five PO4 tetrahedra, an edgeedge with one CaO7 pentagonal bipyramid, and an edgeedge with one PO4 tetrahedra. There are a spread of Ca–O bond distances ranging from 2.31–2.60 Å. There are four inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one CaO7 pentagonal bipyramid, a cornercorner with one PO4 tetrahedra, and an edgeedge with one CaO7 pentagonal bipyramid. There are a spread of P–O bond distances ranging from 1.52–1.64 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two equivalent CaO7 pentagonal bipyramids and a cornercorner with one PO4 tetrahedra. There are a spread of P–O bond distances ranging from 1.52–1.64 Å. In the third P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one CaO7 pentagonal bipyramid and a cornercorner with one PO4 tetrahedra. There are a spread of P–O bond distances ranging from 1.53–1.64 Å. In the fourth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one CaO7 pentagonal bipyramid and a cornercorner with one PO4 tetrahedra. There is three shorter (1.53 Å) and one longer (1.63 Å) P–O bond length. There are fourteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent Ba2+ and one P5+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to one Ba2+, two Ca2+, and one P5+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to one Ba2+, two equivalent Ca2+, and one P5+ atom. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to one Ba2+ and two P5+ atoms. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to one Ba2+, two Ca2+, and one P5+ atom. In the sixth O2- site, O2- is bonded in a 1-coordinate geometry to one Ba2+, two Ca2+, and one P5+ atom. In the seventh O2- site, O2- is bonded in a 1-coordinate geometry to two Ba2+, one Ca2+, and one P5+ atom. In the eighth O2- site, O2- is bonded in a 1-coordinate geometry to two Ba2+, one Ca2+, and one P5+ atom. In the ninth O2- site, O2- is bonded in a distorted single-bond geometry to three Ba2+ and one P5+ atom. In the tenth O2- site, O2- is bonded in a 2-coordinate geometry to two Ba2+, one Ca2+, and one P5+ atom. In the eleventh O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Ba2+ and two P5+ atoms. In the twelfth O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent Ba2+, one Ca2+, and one P5+ atom. In the thirteenth O2- site, O2- is bonded in a distorted single-bond geometry to one Ba2+, two Ca2+, and one P5+ atom. In the fourteenth O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent Ba2+, one Ca2+, and one P5+ atom.