Materials Data on K2Be2(Si2O5)3 by Materials Project

Abstract

K2Be2(Si2O5)3 crystallizes in the orthorhombic Cmc2_1 space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of K–O bond distances ranging from 2.70–3.07 Å. In the second K1+ site, K1+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of K–O bond distances ranging from 2.67–3.27 Å. Be2+ is bonded to four O2- atoms to form BeO4 tetrahedra that share corners with four SiO4 tetrahedra and an edgeedge with one BeO4 tetrahedra. There are a spread of Be–O bond distances ranging from 1.59–1.70 Å. There are four inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two equivalent BeO4 tetrahedra and corners with three SiO4 tetrahedra. 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 corners with two equivalent BeO4 tetrahedra and corners with three SiO4 tetrahedra. 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 BeO4 tetrahedra and corners with three SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.59–1.66 Å. In the fourth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one BeO4 tetrahedra and corners with three SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.60–1.66 Å. There are ten inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the second O2- site, O2- is bonded in a 2-coordinate geometry to one K1+ and two equivalent Si4+ atoms. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two K1+, one Be2+, and one Si4+ atom. In the fourth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two K1+, one Be2+, and one Si4+ atom. In the fifth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one K1+ and two Si4+ atoms. In the sixth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one K1+ and two Si4+ atoms. In the seventh O2- site, O2- is bonded in a distorted T-shaped geometry to two equivalent 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 distorted T-shaped geometry to two equivalent Be2+ and one Si4+ atom. In the tenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one K1+ and two equivalent Si4+ atoms.