DOE OSTI2020
Mn3Zn(FeO2)8 is Spinel-derived structured and crystallizes in the trigonal R3m space group. The structure is three-dimensional. there are three inequivalent Mn2+ sites. In the first Mn2+ site, Mn2+ is bonded to four O2- atoms to form MnO4 tetrahedra that share corners with twelve FeO6 octahedra. The corner-sharing octahedral tilt angles are 59°. All Mn–O bond lengths are 2.04 Å. In the second Mn2+ site, Mn2+ is bonded to four O2- atoms to form MnO4 tetrahedra that share corners with twelve FeO6 octahedra. The corner-sharing octahedra tilt angles range from 58–59°. There are one shorter (2.03 Å) and three longer (2.04 Å) Mn–O bond lengths. In the third Mn2+ site, Mn2+ is bonded to four O2- atoms to form MnO4 tetrahedra that share corners with twelve FeO6 octahedra. The corner-sharing octahedra tilt angles range from 58–59°. There are one shorter (2.02 Å) and three longer (2.06 Å) Mn–O bond lengths. There are four inequivalent Fe3+ sites. In the first Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six MnO4 tetrahedra and edges with six FeO6 octahedra. All Fe–O bond lengths are 2.05 Å. In the second Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with three equivalent MnO4 tetrahedra, corners with three equivalent ZnO4 tetrahedra, and edges with six FeO6 octahedra. There are three shorter (2.02 Å) and three longer (2.03 Å) Fe–O bond lengths. In the third Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with two equivalent ZnO4 tetrahedra, corners with four MnO4 tetrahedra, and edges with six FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.04–2.06 Å. In the fourth Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share a cornercorner with one ZnO4 tetrahedra, corners with five MnO4 tetrahedra, and edges with six FeO6 octahedra. There are two shorter (2.04 Å) and four longer (2.06 Å) Fe–O bond lengths. Zn2+ is bonded to four O2- atoms to form ZnO4 tetrahedra that share corners with twelve FeO6 octahedra. The corner-sharing octahedra tilt angles range from 57–59°. There are one shorter (1.99 Å) and three longer (2.03 Å) Zn–O bond lengths. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded to one Mn2+ and three equivalent Fe3+ atoms to form distorted OMnFe3 trigonal pyramids that share corners with twelve OMnFe3 trigonal pyramids and edges with three equivalent OZnFe3 trigonal pyramids. In the second O2- site, O2- is bonded to three equivalent Fe3+ and one Zn2+ atom to form a mixture of distorted edge and corner-sharing OZnFe3 trigonal pyramids. In the third O2- site, O2- is bonded to three Fe3+ and one Zn2+ atom to form distorted OZnFe3 trigonal pyramids that share corners with twelve OZnFe3 trigonal pyramids and edges with three OMnFe3 trigonal pyramids. In the fourth O2- site, O2- is bonded to one Mn2+ and three Fe3+ atoms to form distorted OMnFe3 trigonal pyramids that share corners with twelve OMnFe3 trigonal pyramids and edges with three OZnFe3 trigonal pyramids. In the fifth O2- site, O2- is bonded to one Mn2+ and three equivalent Fe3+ atoms to form a mixture of distorted edge and corner-sharing OMnFe3 trigonal pyramids. In the sixth O2- site, O2- is bonded to one Mn2+ and three equivalent Fe3+ atoms to form distorted OMnFe3 trigonal pyramids that share corners with twelve OZnFe3 trigonal pyramids and edges with three equivalent OMnFe3 trigonal pyramids. In the seventh O2- site, O2- is bonded to one Mn2+ and three Fe3+ atoms to form a mixture of distorted edge and corner-sharing OMnFe3 trigonal pyramids. In the eighth O2- site, O2- is bonded to one Mn2+ and three Fe3+ atoms to form distorted OMnFe3 trigonal pyramids that share corners with twelve OZnFe3 trigonal pyramids and edges with three OMnFe3 trigonal pyramids.