Materials Data on K4Na2(Si2O5)3 by Materials Project

Abstract

K4Na2(Si2O5)3 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of K–O bond distances ranging from 2.65–2.98 Å. In the second K1+ site, K1+ is bonded in a 2-coordinate geometry to six O2- atoms. There are a spread of K–O bond distances ranging from 2.64–3.21 Å. Na1+ is bonded to five O2- atoms to form distorted NaO5 trigonal bipyramids that share corners with four SiO4 tetrahedra, an edgeedge with one SiO4 tetrahedra, and an edgeedge with one NaO5 trigonal bipyramid. There are a spread of Na–O bond distances ranging from 2.31–2.76 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 three SiO4 tetrahedra and corners with two equivalent NaO5 trigonal bipyramids. 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 corners with three SiO4 tetrahedra and an edgeedge with one NaO5 trigonal bipyramid. There are a spread of Si–O bond distances ranging from 1.59–1.68 Å. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three SiO4 tetrahedra and corners with two equivalent NaO5 trigonal bipyramids. There are a spread of Si–O bond distances ranging from 1.59–1.68 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to one K1+, two equivalent Na1+, and one Si4+ atom. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent K1+ and two Si4+ atoms. In the third O2- site, O2- is bonded in a linear geometry to two equivalent Si4+ atoms. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to two K1+, one Na1+, and one Si4+ atom. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent K1+ and two Si4+ atoms. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to two K1+, one Na1+, and one Si4+ atom. In the seventh O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent K1+ and two Si4+ atoms. In the eighth O2- site, O2- is bonded in a 2-coordinate geometry to one Na1+ and two Si4+ atoms.