DOE OSTI2020
Na2ZrSi3O11 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are four inequivalent Na sites. In the first Na site, Na is bonded to eight O atoms to form NaO8 hexagonal bipyramids that share corners with two equivalent NaO8 hexagonal bipyramids, edges with two equivalent NaO8 hexagonal bipyramids, edges with two equivalent ZrO6 octahedra, and edges with four SiO4 tetrahedra. There are a spread of Na–O bond distances ranging from 2.38–2.69 Å. In the second Na site, Na is bonded to eight O atoms to form NaO8 hexagonal bipyramids that share edges with two equivalent NaO8 hexagonal bipyramids, edges with two equivalent ZrO6 octahedra, and edges with four SiO4 tetrahedra. There are a spread of Na–O bond distances ranging from 2.36–2.70 Å. In the third Na site, Na is bonded to eight O atoms to form NaO8 hexagonal bipyramids that share corners with two equivalent NaO8 hexagonal bipyramids, edges with two equivalent NaO8 hexagonal bipyramids, edges with two equivalent ZrO6 octahedra, and edges with four SiO4 tetrahedra. There are a spread of Na–O bond distances ranging from 2.39–2.69 Å. In the fourth Na site, Na is bonded to eight O atoms to form NaO8 hexagonal bipyramids that share edges with two equivalent NaO8 hexagonal bipyramids, edges with two equivalent ZrO6 octahedra, and edges with four SiO4 tetrahedra. There are a spread of Na–O bond distances ranging from 2.34–2.71 Å. There are two inequivalent Zr sites. In the first Zr site, Zr is bonded to six O atoms to form ZrO6 octahedra that share corners with six SiO4 tetrahedra and edges with four NaO8 hexagonal bipyramids. There are a spread of Zr–O bond distances ranging from 2.09–2.13 Å. In the second Zr site, Zr is bonded to six O atoms to form ZrO6 octahedra that share corners with six SiO4 tetrahedra and edges with four NaO8 hexagonal bipyramids. There are a spread of Zr–O bond distances ranging from 2.09–2.13 Å. There are three inequivalent Si sites. In the first Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with two ZrO6 octahedra, corners with two SiO4 tetrahedra, and edges with three NaO8 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 23–26°. There are a spread of Si–O bond distances ranging from 1.60–1.66 Å. In the second Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with two ZrO6 octahedra, corners with two SiO4 tetrahedra, and edges with two NaO8 hexagonal bipyramids. The corner-sharing octahedral tilt angles are 22°. There is two shorter (1.62 Å) and two longer (1.66 Å) Si–O bond length. In the third Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with two ZrO6 octahedra, corners with two SiO4 tetrahedra, and edges with three NaO8 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 23–26°. There are a spread of Si–O bond distances ranging from 1.60–1.67 Å. There are eleven inequivalent O sites. In the first O site, O is bonded in a water-like geometry to two Na atoms. In the second O site, O is bonded in a 3-coordinate geometry to one Na, one Zr, and one Si atom. In the third O site, O is bonded in a 3-coordinate geometry to one Na, one Zr, and one Si atom. In the fourth O site, O is bonded in a distorted rectangular see-saw-like geometry to two Na, one Zr, and one Si atom. In the fifth O site, O is bonded in a 3-coordinate geometry to one Na, one Zr, and one Si atom. In the sixth O site, O is bonded in a distorted rectangular see-saw-like geometry to two Na, one Zr, and one Si atom. In the seventh O site, O is bonded in a 3-coordinate geometry to one Na, one Zr, and one Si atom. In the eighth O site, O is bonded in a 3-coordinate geometry to one Na and two Si atoms. In the ninth O site, O is bonded in a 4-coordinate geometry to two Na and two Si atoms. In the tenth O site, O is bonded in a 3-coordinate geometry to one Na and two Si atoms. In the eleventh O site, O is bonded in a water-like geometry to two Na atoms.