Materials Data on CaPIO8 by Materials Project

CaPO8I crystallizes in the monoclinic P2/c space group. The structure is two-dimensional and consists of one CaPO8I sheet oriented in the (0, 1, 0) direction. Ca is bonded to six O atoms to form distorted CaO6 pentagonal pyramids that share corners with two equivalent 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 2.31–2.53 Å. P is bonded to four O atoms to form PO4 tetrahedra that share corners with two equivalent CaO6 pentagonal pyramids and an edgeedge with one CaO6 pentagonal pyramid. There is two shorter (1.51 Å) and two longer (1.63 Å) P–O bond length. There are four inequivalent O sites. In the first O site, O is bonded in a distorted single-bond geometry to one P and one O atom. The O–O bond length is 1.49 Å. In the second O site, O is bonded in a 1-coordinate geometry to two equivalent Ca and one P atom. In the third O site, O is bonded in a bent 150 degrees geometry to one Ca and one I atom. The O–I bond length is 1.80 Å. In the fourth O site, O is bonded in a water-like geometry to one O and one I atom. The O–I bond length is 2.16 Å. I is bonded in a see-saw-like geometry to four O atoms.

CaPO8I 结晶于单斜晶系（monoclinic）P2/c 空间群（space group）。其结构为二维，由一个沿(0, 1, 0)方向排列的CaPO8I片层组成。Ca与六个O原子键合，形成扭曲的CaO6五角锥（pentagonal pyramid），这些五角锥与两个等价的PO4四面体（tetrahedron）共享顶点，与两个等价的CaO6五角锥共享边，并与一个PO4四面体共享边。Ca-O键长分布在2.31–2.53 Å之间。P与四个O原子键合形成PO4四面体，这些四面体与两个等价的CaO6五角锥共享顶点，并与一个CaO6五角锥共享边。P-O键长存在两种较短的（1.51 Å）和两种较长的（1.63 Å）。结构中存在四个不等价的O位点（site）。在第一个O位点，O以扭曲的单键几何构型与一个P和一个O原子键合，O-O键长为1.49 Å。第二个O位点的O以一配位几何构型（coordination geometry）与两个等价的Ca和一个P原子键合。第三个O位点的O以150度弯曲几何构型与一个Ca和一个I原子键合，O-I键长为1.80 Å。第四个O位点的O以类水几何构型与一个O和一个I原子键合，O-I键长为2.16 Å。I以跷跷板状几何构型（see-saw-like geometry）与四个O原子键合。