Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Na8Si7O18”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

2 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Na8Si7O18 by Materials Project

Na8Si7O18 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. there are three inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to six O2- atoms to form distorted NaO6 octahedra that share corners with six equivalent SiO4 tetrahedra, faces with three equivalent NaO8 hexagonal bipyramids, and a faceface with one SiO6 octahedra. There are three shorter (2.23 Å) and three longer (2.46 Å) Na–O bond lengths. In the second Na1+ site, Na1+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are four shorter (2.55 Å) and four longer (2.63 Å) Na–O bond lengths. In the third Na1+ site, Na1+ is bonded to eight O2- atoms to form distorted NaO8 hexagonal bipyramids that share corners with four equivalent NaO8 hexagonal bipyramids, corners with two equivalent SiO4 tetrahedra, edges with two equivalent SiO6 octahedra, edges with four equivalent SiO4 tetrahedra, and faces with two equivalent NaO6 octahedra. There are a spread of Na–O bond distances ranging from 2.28–2.72 Å. There are two inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to six equivalent O2- atoms to form SiO6 octahedra that share corners with six equivalent SiO4 tetrahedra, edges with six equivalent NaO8 hexagonal bipyramids, and faces with two equivalent NaO6 octahedra. All Si–O bond lengths are 1.83 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one NaO8 hexagonal bipyramid, a cornercorner with one SiO6 octahedra, corners with two equivalent NaO6 octahedra, corners with two equivalent SiO4 tetrahedra, and edges with two equivalent NaO8 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 30–58°. There are a spread of Si–O bond distances ranging from 1.59–1.68 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to three Na1+ and two equivalent Si4+ atoms to form a mixture of distorted edge and corner-sharing ONa3Si2 trigonal bipyramids. In the second O2- site, O2- is bonded in a 2-coordinate geometry to three Na1+ and two Si4+ atoms. In the third O2- site, O2- is bonded in a 5-coordinate geometry to four Na1+ and one Si4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Na8Si7O18 by Materials Project

Na8Si7O18 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are eight inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 4-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.22–3.03 Å. In the second Na1+ site, Na1+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. There are a spread of Na–O bond distances ranging from 2.17–2.26 Å. In the third 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 2.31–2.88 Å. In the fourth Na1+ site, Na1+ is bonded in a distorted rectangular see-saw-like geometry to four O2- atoms. There are a spread of Na–O bond distances ranging from 2.29–2.89 Å. In the fifth 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 2.27–2.50 Å. In the sixth Na1+ site, Na1+ is bonded in a distorted rectangular see-saw-like geometry to four O2- atoms. There are a spread of Na–O bond distances ranging from 2.18–2.58 Å. In the seventh Na1+ site, Na1+ is bonded in a distorted T-shaped geometry to three O2- atoms. There are a spread of Na–O bond distances ranging from 2.18–2.36 Å. In the eighth 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 2.25–2.55 Å. There are seven inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded in a bent 120 degrees geometry to two O2- atoms. Both Si–O bond lengths are 1.63 Å. In the second Si4+ site, Si4+ is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of Si–O bond distances ranging from 1.57–1.70 Å. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.59–1.74 Å. In the fourth Si4+ site, Si4+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.57 Å) and one longer (1.64 Å) Si–O bond length. In the fifth Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.58–1.71 Å. In the sixth Si4+ site, Si4+ is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of Si–O bond distances ranging from 1.61–1.83 Å. In the seventh Si4+ site, Si4+ is bonded in a water-like geometry to two O2- atoms. There is one shorter (1.56 Å) and one longer (1.66 Å) Si–O bond length. There are eighteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to three Na1+ and one Si4+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to three Na1+ and one Si4+ atom. In the third O2- site, O2- is bonded in a distorted T-shaped geometry to two Na1+ and one Si4+ atom. In the fourth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Na1+ and one Si4+ atom. In the fifth O2- site, O2- is bonded in a 1-coordinate geometry to two Na1+ and one Si4+ atom. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to three Na1+ and one Si4+ atom. In the seventh O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to two Na1+ and one Si4+ atom. In the eighth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two Si4+ atoms. In the ninth O2- site, O2- is bonded in a distorted tetrahedral geometry to three Na1+ and one Si4+ atom. In the tenth O2- site, O2- is bonded in a 1-coordinate geometry to four Na1+ and one Si4+ atom. In the eleventh O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two Si4+ atoms. In the twelfth O2- site, O2- is bonded in a 5-coordinate geometry to four Na1+ and one O2- atom. The O–O bond length is 1.48 Å. In the thirteenth O2- site, O2- is bonded in a distorted single-bond geometry to two Na1+, one Si4+, and one O2- atom. In the fourteenth O2- site, O2- is bonded in a bent 120 degrees geometry to two Si4+ atoms. In the fifteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Na1+ and two Si4+ atoms. In the sixteenth O2- site, O2- is bonded in a 2-coordinate geometry to one Na1+ and one Si4+ atom. In the seventeenth O2- site, O2- is bonded in a distorted single-bond geometry to one Na1+ and one Si4+ atom. In the eighteenth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+ and two Si4+ atoms.

36 MATERIALS SCIENCE↗