Materials Data on Mn2As2O9 by Materials Project
Mn2As2O9 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are two inequivalent Mn4+ sites. In the first Mn4+ site, Mn4+ is bonded to six O2- atoms to form MnO6 octahedra that share corners with five AsO4 tetrahedra and edges with two equivalent MnO6 octahedra. There are a spread of Mn–O bond distances ranging from 1.74–2.18 Å. In the second Mn4+ site, Mn4+ is bonded to six O2- atoms to form distorted MnO6 octahedra that share corners with five AsO4 tetrahedra and edges with two equivalent MnO6 octahedra. There are a spread of Mn–O bond distances ranging from 1.75–2.23 Å. There are two inequivalent As5+ sites. In the first As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with five MnO6 octahedra and a cornercorner with one AsO4 tetrahedra. The corner-sharing octahedra tilt angles range from 49–60°. There are a spread of As–O bond distances ranging from 1.68–1.79 Å. In the second As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with five MnO6 octahedra and a cornercorner with one AsO4 tetrahedra. The corner-sharing octahedra tilt angles range from 49–59°. There are a spread of As–O bond distances ranging from 1.69–1.79 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to two Mn4+ and one As5+ atom. In the second O2- site, O2- is bonded in a bent 120 degrees geometry to one Mn4+ and one As5+ atom. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to two Mn4+ and one As5+ atom. In the fourth O2- site, O2- is bonded in a single-bond geometry to one Mn4+ atom. In the fifth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Mn4+ and one As5+ atom. In the sixth O2- site, O2- is bonded in a single-bond geometry to one Mn4+ atom. In the seventh O2- site, O2- is bonded in a bent 120 degrees geometry to one Mn4+ and one As5+ atom. In the eighth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Mn4+ and one As5+ atom. In the ninth O2- site, O2- is bonded in a bent 120 degrees geometry to two As5+ atoms.