Materials Data on CaBePO4F by Materials Project
CaBePO4F crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Ca2+ is bonded in a 8-coordinate geometry to six O2- and two equivalent F1- atoms. There are a spread of Ca–O bond distances ranging from 2.36–2.73 Å. There are one shorter (2.41 Å) and one longer (2.53 Å) Ca–F bond lengths. Be2+ is bonded to three O2- and one F1- atom to form BeO3F tetrahedra that share corners with three equivalent PO4 tetrahedra. There are a spread of Be–O bond distances ranging from 1.61–1.66 Å. The Be–F bond length is 1.58 Å. P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three equivalent BeO3F tetrahedra. There are a spread of P–O bond distances ranging from 1.53–1.57 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two equivalent Ca2+, one Be2+, and one P5+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to one Ca2+, one Be2+, and one P5+ atom. In the third O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Ca2+, one Be2+, and one P5+ atom. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent Ca2+ and one P5+ atom. F1- is bonded in a distorted single-bond geometry to two equivalent Ca2+ and one Be2+ atom.