DOI: 10.17188/1207863
title: Materials Data on Ca3Er3Ge2BO13 by Materials Project

description: Ca3Er3BGe2O13 crystallizes in the orthorhombic Pnn2 space group. The structure is three-dimensional. there are two inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to seven O2- atoms to form distorted CaO7 pentagonal bipyramids that share a cornercorner with one CaO7 pentagonal bipyramid, corners with three ErO7 pentagonal bipyramids, corners with four GeO4 tetrahedra, an edgeedge with one BO4 tetrahedra, and faces with three ErO7 pentagonal bipyramids. There are a spread of Ca–O bond distances ranging from 2.34–2.52 Å. In the second Ca2+ site, Ca2+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Ca–O bond distances ranging from 2.37–2.52 Å. There are two inequivalent Er3+ sites. In the first Er3+ site, Er3+ is bonded to seven O2- atoms to form distorted ErO7 pentagonal bipyramids that share corners with two equivalent CaO7 pentagonal bipyramids, corners with two ErO7 pentagonal bipyramids, corners with four GeO4 tetrahedra, an edgeedge with one BO4 tetrahedra, a faceface with one ErO7 pentagonal bipyramid, and faces with two equivalent CaO7 pentagonal bipyramids. There are a spread of Er–O bond distances ranging from 2.27–2.39 Å. In the second Er3+ site, Er3+ is bonded to seven O2- atoms to form distorted ErO7 pentagonal bipyramids that share corners with two equivalent CaO7 pentagonal bipyramids, corners with two equivalent ErO7 pentagonal bipyramids, corners with four GeO4 tetrahedra, an edgeedge with one BO4 tetrahedra, faces with two equivalent CaO7 pentagonal bipyramids, and faces with two equivalent ErO7 pentagonal bipyramids. There are a spread of Er–O bond distances ranging from 2.28–2.36 Å. B3+ is bonded to four O2- atoms to form BO4 tetrahedra that share edges with two equivalent CaO7 pentagonal bipyramids and edges with three ErO7 pentagonal bipyramids. There is two shorter (1.48 Å) and two longer (1.50 Å) B–O bond length. There are two inequivalent Ge4+ sites. In the first Ge4+ site, Ge4+ is bonded to four O2- atoms to form GeO4 tetrahedra that share corners with four equivalent CaO7 pentagonal bipyramids and corners with six ErO7 pentagonal bipyramids. There is two shorter (1.79 Å) and two longer (1.81 Å) Ge–O bond length. In the second Ge4+ site, Ge4+ is bonded to four O2- atoms to form GeO4 tetrahedra that share corners with four equivalent CaO7 pentagonal bipyramids and corners with six ErO7 pentagonal bipyramids. There is two shorter (1.77 Å) and two longer (1.78 Å) Ge–O bond length. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Ca2+, two Er3+, and one Ge4+ atom. In the second O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+, one Er3+, and one Ge4+ atom. In the third O2- site, O2- is bonded to three Ca2+ and three Er3+ atoms to form corner-sharing OCa3Er3 octahedra. In the fourth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Ca2+, two Er3+, and one Ge4+ atom. In the fifth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+, one Er3+, and one Ge4+ atom. In the sixth O2- site, O2- is bonded to two Ca2+, one Er3+, and one B3+ atom to form distorted OCa2ErB trigonal pyramids that share corners with three equivalent OCa3Er3 octahedra and edges with three OCa2ErB trigonal pyramids. The corner-sharing octahedra tilt angles range from 31–33°. In the seventh O2- site, O2- is bonded to one Ca2+, two Er3+, and one B3+ atom to form distorted OCaEr2B trigonal pyramids that share corners with three equivalent OCa3Er3 octahedra and edges with three OCa2ErB trigonal pyramids. The corner-sharing octahedra tilt angles range from 30–32°.