Materials Data on Ba3Ta6Si4O23 by Materials Project
Ba3Si4Ta6O23 crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. Ba2+ is bonded in a 10-coordinate geometry to ten O2- atoms. There are a spread of Ba–O bond distances ranging from 2.82–2.95 Å. Ta4+ is bonded to five O2- atoms to form TaO5 square pyramids that share corners with three equivalent TaO5 square pyramids and corners with two equivalent SiO4 tetrahedra. There are three shorter (1.95 Å) and two longer (2.06 Å) Ta–O bond lengths. Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three equivalent TaO5 square pyramids and a cornercorner with one SiO4 tetrahedra. There is one shorter (1.61 Å) and three longer (1.64 Å) Si–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Ba2+ and two equivalent Ta4+ atoms. In the second O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ba2+, one Ta4+, and one Si4+ atom. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Ta4+ atoms. In the fourth O2- site, O2- is bonded in a linear geometry to two equivalent Si4+ atoms.