Materials Data on MgCr8Fe3O16 by Materials Project
MgCr8Fe3O16 is Spinel-derived structured and crystallizes in the tetragonal P-4m2 space group. The structure is three-dimensional. Mg2+ is bonded to four equivalent O2- atoms to form MgO4 tetrahedra that share corners with twelve CrO6 octahedra. The corner-sharing octahedra tilt angles range from 58–59°. All Mg–O bond lengths are 2.02 Å. There are two inequivalent Cr3+ sites. In the first Cr3+ site, Cr3+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with two equivalent MgO4 tetrahedra, corners with four FeO4 tetrahedra, and edges with six CrO6 octahedra. There are two shorter (2.03 Å) and four longer (2.04 Å) Cr–O bond lengths. In the second Cr3+ site, Cr3+ is bonded to six O2- atoms to form CrO6 octahedra that share a cornercorner with one MgO4 tetrahedra, corners with five FeO4 tetrahedra, and edges with six CrO6 octahedra. There are five shorter (2.03 Å) and one longer (2.04 Å) Cr–O bond lengths. There are two inequivalent Fe2+ sites. In the first Fe2+ site, Fe2+ is bonded to four equivalent O2- atoms to form FeO4 tetrahedra that share corners with twelve CrO6 octahedra. The corner-sharing octahedral tilt angles are 59°. All Fe–O bond lengths are 2.04 Å. In the second Fe2+ site, Fe2+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with twelve CrO6 octahedra. The corner-sharing octahedra tilt angles range from 59–60°. All Fe–O bond lengths are 2.04 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded to three Cr3+ and one Fe2+ atom to form a mixture of distorted corner and edge-sharing OCr3Fe trigonal pyramids. In the second O2- site, O2- is bonded to one Mg2+ and three Cr3+ atoms to form a mixture of distorted corner and edge-sharing OMgCr3 trigonal pyramids. In the third O2- site, O2- is bonded to three equivalent Cr3+ and one Fe2+ atom to form a mixture of distorted corner and edge-sharing OCr3Fe trigonal pyramids. In the fourth O2- site, O2- is bonded to three equivalent Cr3+ and one Fe2+ atom to form a mixture of distorted corner and edge-sharing OCr3Fe trigonal pyramids.