Materials Data on NaCaBe2B2O6F by Materials Project
NaCaBe2B2O6F crystallizes in the monoclinic Cc space group. The structure is three-dimensional. Na1+ is bonded in a 6-coordinate geometry to four O2- and two equivalent F1- atoms. There are a spread of Na–O bond distances ranging from 2.49–2.63 Å. There are one shorter (2.43 Å) and one longer (2.56 Å) Na–F bond lengths. Ca2+ is bonded to six O2- atoms to form distorted CaO6 octahedra that share corners with six BeO3F tetrahedra. There are a spread of Ca–O bond distances ranging from 2.37–2.43 Å. There are two inequivalent Be2+ sites. In the first Be2+ site, Be2+ is bonded to three O2- and one F1- atom to form BeO3F tetrahedra that share corners with three equivalent CaO6 octahedra and a cornercorner with one BeO3F tetrahedra. The corner-sharing octahedra tilt angles range from 62–74°. There are a spread of Be–O bond distances ranging from 1.60–1.62 Å. The Be–F bond length is 1.68 Å. In the second Be2+ site, Be2+ is bonded to three O2- and one F1- atom to form BeO3F tetrahedra that share corners with three equivalent CaO6 octahedra and a cornercorner with one BeO3F tetrahedra. The corner-sharing octahedra tilt angles range from 63–77°. There are a spread of Be–O bond distances ranging from 1.60–1.63 Å. The Be–F bond length is 1.66 Å. There are two inequivalent B3+ sites. In the first B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. There is one shorter (1.38 Å) and two longer (1.39 Å) B–O bond length. In the second B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. There is two shorter (1.38 Å) and one longer (1.39 Å) B–O bond length. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to one Na1+, one Ca2+, one Be2+, and one B3+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+, one Be2+, and one B3+ atom. In the third O2- site, O2- is bonded in a 4-coordinate geometry to one Na1+, one Ca2+, one Be2+, and one B3+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+, one Be2+, and one B3+ atom. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to one Na1+, one Ca2+, one Be2+, and one B3+ atom. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to one Na1+, one Ca2+, one Be2+, and one B3+ atom. F1- is bonded in a distorted bent 150 degrees geometry to two equivalent Na1+ and two Be2+ atoms.