Materials Data on CaMn2P2O9 by Materials Project
CaMn2P2O9 crystallizes in the orthorhombic Pnma 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 2.35–2.54 Å. There are two inequivalent Mn3+ sites. In the first Mn3+ site, Mn3+ is bonded to six O2- atoms to form MnO6 octahedra that share corners with two equivalent MnO6 octahedra, corners with three equivalent PO4 tetrahedra, and an edgeedge with one PO4 tetrahedra. The corner-sharing octahedral tilt angles are 55°. There are a spread of Mn–O bond distances ranging from 1.91–2.13 Å. In the second Mn3+ site, Mn3+ is bonded to six O2- atoms to form MnO6 octahedra that share corners with two equivalent MnO6 octahedra, corners with four PO4 tetrahedra, and edges with two equivalent MnO6 octahedra. The corner-sharing octahedral tilt angles are 55°. There are two shorter (2.04 Å) and four longer (2.13 Å) Mn–O bond lengths. There are two inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with five MnO6 octahedra. The corner-sharing octahedra tilt angles range from 15–53°. There is one shorter (1.52 Å) and three longer (1.55 Å) P–O bond length. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two equivalent MnO6 octahedra and an edgeedge with one MnO6 octahedra. The corner-sharing octahedral tilt angles are 49°. There are a spread of P–O bond distances ranging from 1.54–1.58 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to three Mn3+ atoms. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+, one Mn3+, and one P5+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+, one Mn3+, and one P5+ atom. In the fourth O2- site, O2- is bonded in a linear geometry to one Mn3+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a 1-coordinate geometry to one Ca2+, one Mn3+, and one P5+ atom. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ca2+, one Mn3+, and one P5+ atom. In the seventh O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Mn3+ and one P5+ atom.