Materials Data on Ca2Mn2Si4O17 by Materials Project
Ca2Mn2Si4O17 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Ca2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ca–O bond distances ranging from 2.27–2.67 Å. Mn7+ is bonded to six O2- atoms to form MnO6 octahedra that share corners with four equivalent SiO4 tetrahedra and edges with two equivalent MnO6 octahedra. There are a spread of Mn–O bond distances ranging from 1.88–1.99 Å. There are two inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with four equivalent MnO6 octahedra and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 50–59°. There are a spread of Si–O bond distances ranging from 1.63–1.68 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.61–1.71 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ca2+, one Mn7+, and one Si4+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Mn7+ and one Si4+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+ and two Si4+ atoms. In the fourth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Ca2+ and one Si4+ atom. In the fifth O2- site, O2- is bonded in a linear geometry to two equivalent Si4+ atoms. In the sixth O2- site, O2- is bonded in a water-like geometry to two equivalent Mn7+ atoms. In the seventh O2- site, O2- is bonded in a distorted single-bond geometry to one Ca2+ atom.