Materials Data on NaTb(SiO3)2 by Materials Project
NaTb(SiO3)2 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Na1+ is bonded in a 3-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.35–3.00 Å. Tb3+ is bonded to seven O2- atoms to form TbO7 pentagonal bipyramids that share corners with four SiO4 tetrahedra, edges with two equivalent TbO7 pentagonal bipyramids, and edges with two SiO4 tetrahedra. There are a spread of Tb–O bond distances ranging from 2.24–2.52 Å. There are two inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two equivalent TbO7 pentagonal bipyramids, corners with two equivalent SiO4 tetrahedra, and an edgeedge with one TbO7 pentagonal bipyramid. There are a spread of Si–O bond distances ranging from 1.61–1.67 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two equivalent TbO7 pentagonal bipyramids, corners with two equivalent SiO4 tetrahedra, and an edgeedge with one TbO7 pentagonal bipyramid. There are a spread of Si–O bond distances ranging from 1.60–1.67 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Tb3+ and one Si4+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Na1+, one Tb3+, and one Si4+ atom. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to one Na1+ and two Si4+ atoms. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to one Tb3+ and two Si4+ atoms. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to one Na1+, two equivalent Tb3+, and one Si4+ atom. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Na1+, one Tb3+, and one Si4+ atom.