DOI: 10.17188/1350653
title: Materials Data on Na6Si2O7 by Materials Project

description: Na6Si2O7 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are twenty-four inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to five O2- atoms to form distorted NaO5 trigonal bipyramids that share a cornercorner with one NaO4 tetrahedra, corners with three SiO4 tetrahedra, corners with two equivalent NaO5 trigonal bipyramids, an edgeedge with one NaO4 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 2.34–2.54 Å. In the second Na1+ site, Na1+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Na–O bond distances ranging from 2.30–2.71 Å. In the third Na1+ site, Na1+ is bonded in a 5-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.39–3.05 Å. In the fourth Na1+ site, Na1+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Na–O bond distances ranging from 2.28–2.56 Å. In the fifth Na1+ site, Na1+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Na–O bond distances ranging from 2.31–2.79 Å. In the sixth Na1+ site, Na1+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Na–O bond distances ranging from 2.36–2.54 Å. In the seventh Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.33–2.85 Å. In the eighth Na1+ site, Na1+ is bonded to five O2- atoms to form distorted NaO5 trigonal bipyramids that share a cornercorner with one NaO4 tetrahedra, corners with three SiO4 tetrahedra, corners with two NaO5 trigonal bipyramids, and an edgeedge with one SiO4 tetrahedra. There are a spread of Na–O bond distances ranging from 2.36–2.66 Å. In the ninth Na1+ site, Na1+ is bonded to five O2- atoms to form distorted NaO5 trigonal bipyramids that share corners with two equivalent NaO4 tetrahedra, corners with three SiO4 tetrahedra, corners with three NaO5 trigonal bipyramids, and an edgeedge with one SiO4 tetrahedra. There are a spread of Na–O bond distances ranging from 2.30–2.60 Å. In the tenth Na1+ site, Na1+ is bonded to four O2- atoms to form NaO4 tetrahedra that share corners with four SiO4 tetrahedra and edges with two equivalent NaO4 tetrahedra. There are a spread of Na–O bond distances ranging from 2.30–2.42 Å. In the eleventh Na1+ site, Na1+ is bonded to four O2- atoms to form distorted NaO4 tetrahedra that share corners with two equivalent NaO4 tetrahedra, corners with four SiO4 tetrahedra, and edges with two equivalent NaO4 tetrahedra. There are a spread of Na–O bond distances ranging from 2.32–2.54 Å. In the twelfth Na1+ site, Na1+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Na–O bond distances ranging from 2.26–2.63 Å. In the thirteenth Na1+ site, Na1+ is bonded to four O2- atoms to form distorted NaO4 tetrahedra that share corners with four SiO4 tetrahedra, corners with two equivalent NaO5 trigonal bipyramids, and an edgeedge with one NaO5 trigonal bipyramid. There are a spread of Na–O bond distances ranging from 2.33–2.38 Å. In the fourteenth Na1+ site, Na1+ is bonded to five O2- atoms to form distorted NaO5 trigonal bipyramids that share a cornercorner with one NaO4 tetrahedra, corners with three SiO4 tetrahedra, a cornercorner with one NaO5 trigonal bipyramid, 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 2.37–2.65 Å. In the fifteenth Na1+ site, Na1+ is bonded in a 4-coordinate geometry to four O2- atoms. There are three shorter (2.29 Å) and one longer (2.35 Å) Na–O bond lengths. In the sixteenth Na1+ site, Na1+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Na–O bond distances ranging from 2.28–2.53 Å. In the seventeenth Na1+ site, Na1+ is bonded to four O2- atoms to form distorted NaO4 tetrahedra that share corners with two equivalent NaO4 tetrahedra, corners with three SiO4 tetrahedra, corners with two NaO5 trigonal bipyramids, and an edgeedge with one SiO4 tetrahedra. There are a spread of Na–O bond distances ranging from 2.27–2.41 Å. In the eighteenth Na1+ site, Na1+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Na–O bond distances ranging from 2.27–2.44 Å. In the nineteenth Na1+ site, Na1+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Na–O bond distances ranging from 2.32–2.67 Å. In the twentieth Na1+ site, Na1+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Na–O bond distances ranging from 2.28–2.58 Å. In the twenty-first Na1+ site, Na1+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Na–O bond distances ranging from 2.35–2.85 Å. In the twenty-second Na1+ site, Na1+ is bonded to four O2- atoms to form distorted NaO4 tetrahedra that share corners with four SiO4 tetrahedra and a cornercorner with one NaO5 trigonal bipyramid. There are a spread of Na–O bond distances ranging from 2.33–2.36 Å. In the twenty-third Na1+ site, Na1+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Na–O bond distances ranging from 2.31–2.44 Å. In the twenty-fourth Na1+ site, Na1+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Na–O bond distances ranging from 2.28–2.45 Å. There are eight 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 NaO4 tetrahedra, a cornercorner with one SiO4 tetrahedra, corners with three NaO5 trigonal bipyramids, and an edgeedge with one NaO5 trigonal bipyramid. There are a spread of Si–O bond distances ranging from 1.64–1.70 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one SiO4 tetrahedra, corners with three NaO4 tetrahedra, and a cornercorner with one NaO5 trigonal bipyramid. There are a spread of Si–O bond distances ranging from 1.64–1.70 Å. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one SiO4 tetrahedra, corners with two equivalent NaO4 tetrahedra, a cornercorner with one NaO5 trigonal bipyramid, an edgeedge with one NaO4 tetrahedra, and an edgeedge with one NaO5 trigonal bipyramid. There are a spread of Si–O bond distances ranging from 1.64–1.70 Å. In the fourth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one SiO4 tetrahedra, corners with two equivalent NaO4 tetrahedra, corners with two NaO5 trigonal bipyramids, and an edgeedge with one NaO5 trigonal bipyramid. There is three shorter (1.64 Å) and one longer (1.71 Å) Si–O bond length. In the fifth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one NaO4 tetrahedra, a cornercorner with one SiO4 tetrahedra, corners with two NaO5 trigonal bipyramids, and an edgeedge with one NaO5 trigonal bipyramid. There is three shorter (1.64 Å) and one longer (1.71 Å) Si–O bond length. In the sixth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one SiO4 tetrahedra and corners with four NaO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.64–1.70 Å. In the seventh Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one SiO4 tetrahedra, corners with three NaO4 tetrahedra, and corners with two NaO5 trigonal bipyramids. There are a spread of Si–O bond distances ranging from 1.64–1.70 Å. In the eighth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one SiO4 tetrahedra, corners with three NaO4 tetrahedra, and a cornercorner with one NaO5 trigonal bipyramid. There are a spread of Si–O bond distances ranging from 1.64–1.70 Å. There are twenty-eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a 6-coordinate geometry to five Na1+ and one Si4+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to four Na1+ and one Si4+ atom. In the third O2- site, O2- is bonded in a 6-coordinate geometry to five Na1+ and one Si4+ atom. In the fourth O2- site, O2- is bonded to two Na1+ and two Si4+ atoms to form distorted corner-sharing ONa2Si2 trigonal pyramids. In the fifth O2- site, O2- is bonded in a 5-coordinate geometry to four Na1+ and one Si4+ atom. In the sixth O2- site, O2- is bonded in a 1-coordinate geometry to four Na1+ and one Si4+ atom. In the seventh O2- site, O2- is bonded in a 5-coordinate geometry to four Na1+ and one Si4+ atom. In the eighth O2- site, O2- is bonded in a 6-coordinate geometry to five Na1+ and one Si4+ atom. In the ninth O2- site, O2- is bonded to four Na1+ and one Si4+ atom to form distorted ONa4Si trigonal bipyramids that share corners with two equivalent ONa4Si trigonal bipyramids, a cornercorner with one ONa2Si2 trigonal pyramid, and an edgeedge with one ONa2Si2 trigonal pyramid. In the tenth O2- site, O2- is bonded to four Na1+ and one Si4+ atom to form distorted ONa4Si trigonal bipyramids that share corners with two equivalent ONa4Si trigonal bipyramids, corners with three ONa2Si2 trigonal pyramids, and an edgeedge with one ONa4Si trigonal bipyramid. In the eleventh O2- site, O2- is bonded to two Na1+ and two Si4+ atoms to form a mixture of distorted edge and corner-sharing ONa2Si2 trigonal pyramids. In the twelfth O2- site, O2- is bonded in a 1-coordinate geometry to five Na1+ and one Si4+ atom. In the thirteenth O2- site, O2- is bonded in a 1-coordinate geometry to five Na1+ and one Si4+ atom. In the fourteenth O2- site, O2- is bonded in a 1-coordinate geometry to three Na1+ and one Si4+ atom. In the fifteenth O2- site, O2- is bonded in a 1-coordinate geometry to four Na1+ and one Si4+ atom. In the sixteenth O2- site, O2- is bonded in a 1-coordinate geometry to five Na1+ and one Si4+ atom. In the seventeenth O2- site, O2- is bonded in a 1-coordinate geometry to five Na1+ and one Si4+ atom. In the eighteenth O2- site, O2- is bonded to two Na1+ and two Si4+ atoms to form distorted corner-sharing ONa2Si2 trigonal pyramids. In the nineteenth O2- site, O2- is bonded in a 5-coordinate geometry to four Na1+ and one Si4+ atom. In the twentieth O2- site, O2- is bonded in a 6-coordinate geometry to five Na1+ and one Si4+ atom. In the twenty-first O2- site, O2- is bonded to four Na1+ and one Si4+ atom to form distorted ONa4Si trigonal bipyramids that share a cornercorner with one ONa2Si2 trigonal pyramid and an edgeedge with one ONa4Si trigonal bipyramid. In the twenty-second O2- site, O2- is bonded in a 1-coordinate geometry to five Na1+ and one Si4+ atom. In the twenty-third O2- site, O2- is bonded in a 1-coordinate geometry to four Na1+ and one Si4+ atom. In the twenty-fourth O2- site, O2- is bonded in a 6-coordinate geometry to five Na1+ and one Si4+ atom. In the twenty-fifth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Na1+ and two Si4+ atoms. In the twenty-sixth O2- site, O2- is bonded in a 1-coordinate geometry to four Na1+ and one Si4+ atom. In the twenty-seventh O2- site, O2- is bonded in a 1-coordinate geometry to four Na1+ and one Si4+ atom. In the twenty-eighth O2- site, O2- is bonded in a 1-coordinate geometry to four Na1+ and one Si4+ atom.