Materials Data on Ba6Na2Si4O15 by Materials Project
Na2Ba6Si4O15 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Na1+ is bonded to six O2- atoms to form NaO6 octahedra that share corners with six SiO4 tetrahedra. There are a spread of Na–O bond distances ranging from 2.34–2.61 Å. There are three inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a 10-coordinate geometry to ten O2- atoms. There are a spread of Ba–O bond distances ranging from 2.79–3.11 Å. In the second Ba2+ site, Ba2+ is bonded in a 1-coordinate geometry to nine O2- atoms. There are a spread of Ba–O bond distances ranging from 2.57–3.08 Å. In the third Ba2+ site, Ba2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Ba–O bond distances ranging from 2.71–3.26 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 four equivalent NaO6 octahedra. The corner-sharing octahedra tilt angles range from 12–40°. There is two shorter (1.65 Å) and two longer (1.67 Å) Si–O bond length. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two equivalent NaO6 octahedra and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 16°. There are a spread of Si–O bond distances ranging from 1.62–1.70 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to one Na1+, four Ba2+, and one Si4+ atom. In the second O2- site, O2- is bonded in a linear geometry to four Ba2+ and two equivalent Si4+ atoms. In the third O2- site, O2- is bonded in a 1-coordinate geometry to one Na1+, three Ba2+, and one Si4+ atom. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to four Ba2+ and one Si4+ atom. In the fifth O2- site, O2- is bonded in a 1-coordinate geometry to one Na1+, four Ba2+, and one Si4+ atom. In the sixth O2- site, O2- is bonded in a 1-coordinate geometry to one Na1+, three Ba2+, and one Si4+ atom. In the seventh O2- site, O2- is bonded in a 6-coordinate geometry to one Na1+, four Ba2+, and one Si4+ atom. In the eighth O2- site, O2- is bonded in a 6-coordinate geometry to one Na1+, four Ba2+, and one Si4+ atom.