Materials Data on K4BaTa6(Si2O13)2 by Materials Project
K4BaTa6(Si2O13)2 crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 4-coordinate geometry to fifteen O2- atoms. There are a spread of K–O bond distances ranging from 2.73–3.33 Å. In the second K1+ site, K1+ is bonded in a 6-coordinate geometry to thirteen O2- atoms. There are a spread of K–O bond distances ranging from 2.90–3.30 Å. Ba2+ is bonded in a 6-coordinate geometry to thirteen O2- atoms. There are a spread of Ba–O bond distances ranging from 2.90–3.28 Å. There are two inequivalent Ta5+ sites. In the first Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with four TaO6 octahedra and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 2–32°. There are a spread of Ta–O bond distances ranging from 1.97–2.05 Å. In the second Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with four TaO6 octahedra and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 2–32°. There are a spread of Ta–O bond distances ranging from 1.96–2.06 Å. Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three TaO6 octahedra and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 23–26°. There is one shorter (1.62 Å) and three longer (1.63 Å) Si–O bond length. There are ten inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two K1+, one Ba2+, one Ta5+, and one Si4+ atom. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two K1+, one Ba2+, one Ta5+, and one Si4+ atom. In the third O2- site, O2- is bonded in a distorted linear geometry to two equivalent K1+ and two equivalent Si4+ atoms. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to two K1+ and two Ta5+ atoms. In the fifth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to four K1+, one Ta5+, and one Si4+ atom. In the sixth O2- site, O2- is bonded in a linear geometry to two equivalent K1+, one Ba2+, and two equivalent Ta5+ atoms. In the seventh O2- site, O2- is bonded in a distorted linear geometry to two equivalent K1+ and two equivalent Ta5+ atoms. In the eighth O2- site, O2- is bonded in a linear geometry to two equivalent K1+ and two equivalent Ta5+ atoms. In the ninth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Ba2+ and two equivalent Ta5+ atoms. In the tenth O2- site, O2- is bonded in a linear geometry to two equivalent K1+, one Ba2+, and two equivalent Ta5+ atoms.