Materials Data on Na2TiSiO5 by Materials Project

Abstract

Na2TiSiO5 crystallizes in the tetragonal P4_2/m space group. The structure is three-dimensional. there are three inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a distorted hexagonal planar geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.73–3.03 Å. In the second Na1+ site, Na1+ is bonded to six O2- atoms to form distorted NaO6 pentagonal pyramids that share corners with two equivalent NaO6 pentagonal pyramids, corners with four SiO4 tetrahedra, corners with two TiO5 trigonal bipyramids, and edges with two TiO5 trigonal bipyramids. There are a spread of Na–O bond distances ranging from 2.39–2.67 Å. In the third Na1+ site, Na1+ is bonded in a distorted linear geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.17–2.80 Å. There are two inequivalent Ti4+ sites. In the first Ti4+ site, Ti4+ is bonded to five O2- atoms to form distorted TiO5 trigonal bipyramids that share corners with two equivalent NaO6 pentagonal pyramids, corners with four SiO4 tetrahedra, and edges with two equivalent NaO6 pentagonal pyramids. There are a spread of Ti–O bond distances ranging from 1.72–2.00 Å. In the second Ti4+ site, Ti4+ is bonded to five O2- atoms to form distorted TiO5 trigonal bipyramids that share corners with two equivalent NaO6 pentagonal pyramids, corners with four SiO4 tetrahedra, and edges with two equivalent NaO6 pentagonal pyramids. There are a spread of Ti–O bond distances ranging from 1.72–1.99 Å. There are three inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four equivalent O2- atoms to form SiO4 tetrahedra that share corners with four equivalent NaO6 pentagonal pyramids and corners with four equivalent TiO5 trigonal bipyramids. All Si–O bond lengths are 1.65 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with four equivalent NaO6 pentagonal pyramids and corners with four TiO5 trigonal bipyramids. There is two shorter (1.64 Å) and two longer (1.65 Å) Si–O bond length. In the third Si4+ site, Si4+ is bonded to four equivalent O2- atoms to form SiO4 tetrahedra that share corners with four equivalent NaO6 pentagonal pyramids and corners with four equivalent TiO5 trigonal bipyramids. All Si–O bond lengths are 1.64 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to two Na1+, one Ti4+, and one Si4+ atom. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one Ti4+, and one Si4+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to two Na1+, one Ti4+, and one Si4+ atom. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one Ti4+, and one Si4+ atom. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to four Na1+ and one Ti4+ atom. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to four Na1+ and one Ti4+ atom.