Materials Data on MnAl6Si4O19 by Materials Project
MnAl6Si4O19 crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. Mn4+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Mn–O bond distances ranging from 1.83–2.46 Å. There are four inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with six AlO6 octahedra and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 49–61°. There are a spread of Al–O bond distances ranging from 1.73–1.79 Å. In the second Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with four AlO6 octahedra and corners with three equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 51–58°. There are a spread of Al–O bond distances ranging from 1.73–1.79 Å. In the third Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two AlO4 tetrahedra, corners with two SiO4 tetrahedra, a cornercorner with one SiO5 trigonal bipyramid, edges with two equivalent AlO6 octahedra, and an edgeedge with one SiO5 trigonal bipyramid. There are a spread of Al–O bond distances ranging from 1.84–2.02 Å. In the fourth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three AlO4 tetrahedra, corners with four SiO4 tetrahedra, and edges with two equivalent AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.85–2.05 Å. There are four inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to five O2- atoms to form SiO5 trigonal bipyramids that share corners with two equivalent AlO6 octahedra, a cornercorner with one SiO4 tetrahedra, and edges with two equivalent AlO6 octahedra. The corner-sharing octahedral tilt angles are 49°. There are a spread of Si–O bond distances ranging from 1.67–1.89 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two equivalent AlO6 octahedra and a cornercorner with one SiO5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 53°. There are a spread of Si–O bond distances ranging from 1.62–1.68 Å. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with six AlO6 octahedra and corners with two equivalent AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 47–55°. There are a spread of Si–O bond distances ranging from 1.61–1.65 Å. In the fourth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with four AlO6 octahedra and corners with three equivalent AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 50–59°. There are a spread of Si–O bond distances ranging from 1.61–1.66 Å. There are fifteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a linear geometry to one Al3+ and one Si4+ atom. In the second O2- site, O2- is bonded in a 4-coordinate geometry to one Mn4+ and three Al3+ atoms. In the third O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Al3+ and one Si4+ atom. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Al3+ and one Si4+ atom. In the fifth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Mn4+ and one Si4+ atom. In the sixth O2- site, O2- is bonded in a bent 120 degrees geometry to two Si4+ atoms. In the seventh O2- site, O2- is bonded in a trigonal planar geometry to three Al3+ atoms. In the eighth O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Al3+ and one Si4+ atom. In the ninth O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Al3+ and one Si4+ atom. In the tenth O2- site, O2- is bonded in a trigonal non-coplanar geometry to two equivalent Al3+ and one Si4+ atom. In the eleventh O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms. In the twelfth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Mn4+, one Al3+, and one Si4+ atom. In the thirteenth O2- site, O2- is bonded in a trigonal planar geometry to two Al3+ and one Si4+ atom. In the fourteenth O2- site, O2- is bonded in a trigonal planar geometry to two Al3+ and one Si4+ atom. In the fifteenth O2- site, O2- is bonded in a trigonal planar geometry to one Mn4+, one Al3+, and one Si4+ atom.