Materials Data on Ba3Nb6(Si2O13)2 by Materials Project
Ba3Nb6Si4O26 crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. Ba2+ is bonded in a 12-coordinate geometry to twelve O2- atoms. There are a spread of Ba–O bond distances ranging from 2.92–3.19 Å. Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with four equivalent NbO6 octahedra and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 4–31°. There are a spread of Nb–O bond distances ranging from 1.95–2.08 Å. Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three equivalent NbO6 octahedra and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 31°. There is one shorter (1.62 Å) and three longer (1.64 Å) Si–O bond length. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a linear geometry to two equivalent Ba2+ and two equivalent Nb5+ atoms. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent Ba2+, one Nb5+, and one Si4+ atom. In the third O2- site, O2- is bonded in a linear geometry to two equivalent Si4+ atoms. In the fourth O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Nb5+ atoms. In the fifth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Ba2+ and two equivalent Nb5+ atoms.