Materials Data on BaEr4Si5O17 by Materials Project
BaEr4Si5O17 crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. Ba2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ba–O bond distances ranging from 2.71–3.10 Å. There are two inequivalent Er3+ sites. In the first Er3+ site, Er3+ is bonded to six O2- atoms to form distorted ErO6 pentagonal pyramids that share corners with six SiO4 tetrahedra, an edgeedge with one ErO6 octahedra, and edges with two equivalent ErO6 pentagonal pyramids. There are a spread of Er–O bond distances ranging from 2.22–2.34 Å. In the second Er3+ site, Er3+ is bonded to six O2- atoms to form distorted ErO6 octahedra that share corners with six SiO4 tetrahedra, an edgeedge with one ErO6 octahedra, and an edgeedge with one ErO6 pentagonal pyramid. There are a spread of Er–O bond distances ranging from 2.19–2.38 Å. There are three inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with four equivalent ErO6 octahedra and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 52–54°. There is two shorter (1.64 Å) and two longer (1.66 Å) Si–O bond length. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two equivalent ErO6 octahedra, corners with three equivalent ErO6 pentagonal pyramids, and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 46–51°. There are a spread of Si–O bond distances ranging from 1.63–1.69 Å. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two equivalent ErO6 octahedra, corners with three equivalent ErO6 pentagonal pyramids, and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 47–58°. There are a spread of Si–O bond distances ranging from 1.63–1.66 Å. There are ten inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Er3+ and one Si4+ atom. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to two Er3+ and one Si4+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to one Ba2+, one Er3+, and one Si4+ atom. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Er3+ and one Si4+ atom. In the fifth O2- site, O2- is bonded in a linear geometry to two equivalent Si4+ atoms. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Er3+ and one Si4+ atom. In the seventh O2- site, O2- is bonded in a 1-coordinate geometry to one Ba2+, two equivalent Er3+, and one Si4+ atom. In the eighth O2- site, O2- is bonded in a 1-coordinate geometry to one Ba2+, two equivalent Er3+, and one Si4+ atom. In the ninth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Ba2+ and two Si4+ atoms. In the tenth O2- site, O2- is bonded in a 3-coordinate geometry to one Ba2+, one Er3+, and one Si4+ atom.