Materials Data on K2Be(Si2O5)2 by Materials Project
K2Be(Si2O5)2 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of K–O bond distances ranging from 2.68–2.96 Å. In the second K1+ site, K1+ is bonded in a 8-coordinate geometry to seven O2- atoms. There are a spread of K–O bond distances ranging from 2.70–3.01 Å. Be2+ is bonded to four O2- atoms to form BeO4 tetrahedra that share corners with four SiO4 tetrahedra. There are a spread of Be–O bond distances ranging from 1.61–1.68 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 a cornercorner with one BeO4 tetrahedra and corners with three SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.59–1.67 Å. In the second 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. 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 1.60–1.67 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 1.59–1.67 Å. There are ten inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one K1+, one Be2+, and one Si4+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to one K1+ and two Si4+ atoms. In the third O2- site, O2- is bonded in a bent 120 degrees geometry to one K1+ and two Si4+ atoms. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent K1+, one Be2+, and one Si4+ atom. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to one K1+ and two Si4+ atoms. In the sixth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one K1+ and two Si4+ atoms. In the seventh O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two K1+, 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 K1+ and two Si4+ atoms. In the tenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one K1+, one Be2+, and one Si4+ atom.