Materials Data on Ba3TaFe3(SiO7)2 by Materials Project

Abstract

Ba3TaFe3Si2O14 is Esseneite-derived structured and crystallizes in the trigonal P321 space group. The structure is three-dimensional. Ba2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ba–O bond distances ranging from 2.72–3.06 Å. Ta5+ is bonded to six equivalent O2- atoms to form TaO6 octahedra that share corners with six equivalent FeO4 tetrahedra. All Ta–O bond lengths are 2.00 Å. Fe3+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with two equivalent TaO6 octahedra and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 56°. There is two shorter (1.89 Å) and two longer (1.93 Å) Fe–O bond length. Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three equivalent FeO4 tetrahedra. There is one shorter (1.62 Å) and three longer (1.66 Å) Si–O bond length. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to three equivalent Ba2+ and one Si4+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ba2+, one Fe3+, and one Si4+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one Ba2+, one Ta5+, and one Fe3+ atom.