DOI: 10.17188/1284653
title: Materials Data on KCa2Be2Al(Si2O5)6 by Materials Project

description: KCa2Be2Al(Si2O5)6 crystallizes in the orthorhombic Ccc2 space group. The structure is three-dimensional. K1+ is bonded in a 12-coordinate geometry to twelve O2- atoms. There are a spread of K–O bond distances ranging from 2.95–3.08 Å. Ca2+ is bonded to six O2- atoms to form distorted CaO6 octahedra that share corners with six SiO4 tetrahedra, an edgeedge with one AlO4 tetrahedra, and edges with two BeO4 tetrahedra. There are a spread of Ca–O bond distances ranging from 2.31–2.49 Å. There are two inequivalent Be2+ sites. In the first Be2+ site, Be2+ is bonded to four O2- atoms to form BeO4 tetrahedra that share corners with four SiO4 tetrahedra and edges with two equivalent CaO6 octahedra. All Be–O bond lengths are 1.66 Å. In the second Be2+ site, Be2+ is bonded to four O2- atoms to form BeO4 tetrahedra that share corners with four SiO4 tetrahedra and edges with two equivalent CaO6 octahedra. All Be–O bond lengths are 1.66 Å. Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with four SiO4 tetrahedra and edges with two equivalent CaO6 octahedra. There is two shorter (1.76 Å) and two longer (1.77 Å) Al–O bond length. There are six inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one CaO6 octahedra, a cornercorner with one BeO4 tetrahedra, and corners with three SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 45°. There are a spread of Si–O bond distances ranging from 1.61–1.65 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one CaO6 octahedra, a cornercorner with one BeO4 tetrahedra, and corners with three SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 50°. There are a spread of Si–O bond distances ranging from 1.61–1.65 Å. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one CaO6 octahedra, a cornercorner with one AlO4 tetrahedra, and corners with three SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 45°. There are a spread of Si–O bond distances ranging from 1.62–1.64 Å. In the fourth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one CaO6 octahedra, a cornercorner with one BeO4 tetrahedra, and corners with three SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 50°. There are a spread of Si–O bond distances ranging from 1.60–1.64 Å. In the fifth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one CaO6 octahedra, a cornercorner with one AlO4 tetrahedra, and corners with three SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 45°. There are a spread of Si–O bond distances ranging from 1.62–1.64 Å. In the sixth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one CaO6 octahedra, a cornercorner with one BeO4 tetrahedra, and corners with three SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 45°. There are a spread of Si–O bond distances ranging from 1.61–1.65 Å. There are fifteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to one K1+ and two Si4+ atoms. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to one K1+ and two Si4+ atoms. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the fourth O2- site, O2- is bonded in a bent 150 degrees geometry to one K1+ and two Si4+ atoms. In the fifth O2- site, O2- is bonded in a bent 150 degrees geometry to one K1+ and two Si4+ atoms. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+, one Be2+, and one Si4+ atom. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to one Ca2+, one Be2+, and one Si4+ atom. In the eighth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the ninth O2- site, O2- is bonded in a 2-coordinate geometry to one Ca2+, one Al3+, and one Si4+ atom. In the tenth O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+, one Be2+, and one Si4+ atom. In the eleventh O2- site, O2- is bonded in a 2-coordinate geometry to one Ca2+, one Be2+, and one Si4+ atom. In the twelfth O2- site, O2- is bonded in a 2-coordinate geometry to one Ca2+, one Al3+, and one Si4+ atom. In the thirteenth O2- site, O2- is bonded in a bent 150 degrees geometry to one K1+ and two Si4+ atoms. In the fourteenth O2- site, O2- is bonded in a bent 150 degrees geometry to one K1+ and two Si4+ atoms. In the fifteenth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms.