Materials Data on BaNaScSi2O7 by Materials Project
NaBaScSi2O7 crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. Na1+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Na–O bond distances ranging from 2.45–2.97 Å. Ba2+ is bonded in a 11-coordinate geometry to eleven O2- atoms. There are a spread of Ba–O bond distances ranging from 2.86–3.09 Å. Sc3+ is bonded to six O2- atoms to form ScO6 octahedra that share corners with six SiO4 tetrahedra. There are a spread of Sc–O bond distances ranging from 2.04–2.24 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 three equivalent ScO6 octahedra and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 15–39°. There are a spread of Si–O bond distances ranging from 1.62–1.69 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three equivalent ScO6 octahedra and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 12–49°. There are a spread of Si–O bond distances ranging from 1.62–1.68 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to one Na1+ and two Si4+ atoms. In the second O2- site, O2- is bonded in a 5-coordinate geometry to one Na1+, two equivalent Ba2+, one Sc3+, and one Si4+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to three equivalent Na1+, one Sc3+, and one Si4+ atom. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to three equivalent Ba2+, one Sc3+, and one Si4+ atom. In the fifth O2- site, O2- is bonded in a distorted linear geometry to one Na1+, two equivalent Ba2+, one Sc3+, and one Si4+ atom.