Materials Data on CaP2O9 by Materials Project
CaP2O9 crystallizes in the triclinic P-1 space group. The structure is two-dimensional and consists of one CaP2O9 sheet oriented in the (0, 0, 1) direction. Ca is bonded to six O atoms to form distorted CaO6 pentagonal pyramids that share corners with four PO4 tetrahedra, edges with two equivalent CaO6 pentagonal pyramids, and an edgeedge with one PO4 tetrahedra. There are a spread of Ca–O bond distances ranging from 2.27–2.59 Å. There are two inequivalent P sites. In the first P site, P is bonded to four O atoms to form PO4 tetrahedra that share corners with three equivalent CaO6 pentagonal pyramids and an edgeedge with one CaO6 pentagonal pyramid. There are a spread of P–O bond distances ranging from 1.50–1.86 Å. In the second P site, P is bonded to four O atoms to form PO4 tetrahedra that share a cornercorner with one CaO6 pentagonal pyramid. There are a spread of P–O bond distances ranging from 1.53–1.55 Å. There are nine inequivalent O sites. In the first O site, O is bonded in a 3-coordinate geometry to two equivalent Ca and one P atom. In the second O site, O is bonded in a distorted trigonal planar geometry to two equivalent Ca and one P atom. In the third O site, O is bonded in a distorted water-like geometry to one Ca and one P atom. In the fourth O site, O is bonded in a distorted bent 120 degrees geometry to one P and one O atom. The O–O bond length is 1.29 Å. In the fifth O site, O is bonded in a distorted linear geometry to one Ca and one P atom. In the sixth O site, O is bonded in a single-bond geometry to one P atom. In the seventh O site, O is bonded in a single-bond geometry to one P atom. In the eighth O site, O is bonded in a single-bond geometry to one P atom. In the ninth O site, O is bonded in a single-bond geometry to one O atom.