Materials Data on Fe2Si2BiO9 by Materials Project

Fe2Si2BiO9 crystallizes in the monoclinic Cm space group. The structure is two-dimensional and consists of one Fe2Si2BiO9 sheet oriented in the (0, 0, 1) direction. Fe+2.50+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with two equivalent SiO4 tetrahedra and edges with three equivalent FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 1.89–2.08 Å. Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two equivalent FeO6 octahedra and corners with three equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 50–56°. There are a spread of Si–O bond distances ranging from 1.62–1.65 Å. Bi5+ is bonded in a distorted trigonal non-coplanar geometry to three O2- atoms. All Bi–O bond lengths are 2.15 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Fe+2.50+ and one Bi5+ atom. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Fe+2.50+ and one Bi5+ atom. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Fe+2.50+ and one Si4+ atom. In the fourth O2- site, O2- is bonded in a water-like geometry to two equivalent Fe+2.50+ atoms. In the fifth O2- site, O2- is bonded in a bent 120 degrees geometry to two equivalent Si4+ atoms. In the sixth O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Si4+ atoms.