Materials Data on Ca5B3O9F by Materials Project
Ca5(BO3)3F crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are three inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ca–O bond distances ranging from 2.35–2.54 Å. In the second Ca2+ site, Ca2+ is bonded to five O2- and one F1- atom to form a mixture of corner and edge-sharing CaO5F octahedra. The corner-sharing octahedra tilt angles range from 65–75°. There are a spread of Ca–O bond distances ranging from 2.30–2.37 Å. The Ca–F bond length is 2.42 Å. In the third Ca2+ site, Ca2+ is bonded to four O2- and two equivalent F1- atoms to form CaO4F2 octahedra that share corners with four equivalent CaO5F octahedra and edges with two equivalent CaO4F2 octahedra. The corner-sharing octahedra tilt angles range from 65–66°. There are a spread of Ca–O bond distances ranging from 2.28–2.41 Å. There are one shorter (2.38 Å) and one longer (2.50 Å) Ca–F bond lengths. There are two inequivalent B3+ sites. In the first B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. All B–O bond lengths are 1.39 Å. In the second B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. All B–O bond lengths are 1.39 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Ca2+ and one B3+ atom. In the second O2- site, O2- is bonded to three Ca2+ and one B3+ atom to form distorted OCa3B tetrahedra that share corners with two equivalent FCa4 tetrahedra and corners with five OCa3B tetrahedra. In the third O2- site, O2- is bonded to three Ca2+ and one B3+ atom to form distorted OCa3B tetrahedra that share corners with two equivalent FCa4 tetrahedra and corners with five OCa3B tetrahedra. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to three Ca2+ and one B3+ atom. In the fifth O2- site, O2- is bonded in a 1-coordinate geometry to three Ca2+ and one B3+ atom. F1- is bonded to four Ca2+ atoms to form FCa4 tetrahedra that share corners with two equivalent FCa4 tetrahedra and corners with eight OCa3B tetrahedra.