DOE OSTI2020
MnCo2O4 is Spinel-like structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are four inequivalent Mn2+ sites. In the first Mn2+ site, Mn2+ is bonded to six O2- atoms to form MnO6 octahedra that share a cornercorner with one MnO4 tetrahedra, corners with five CoO4 tetrahedra, an edgeedge with one MnO6 octahedra, and edges with five CoO6 octahedra. There are a spread of Mn–O bond distances ranging from 1.94–2.20 Å. In the second Mn2+ site, Mn2+ is bonded to four O2- atoms to form MnO4 tetrahedra that share corners with three MnO6 octahedra and corners with nine CoO6 octahedra. The corner-sharing octahedra tilt angles range from 56–64°. There are a spread of Mn–O bond distances ranging from 1.99–2.05 Å. In the third Mn2+ site, Mn2+ is bonded to six O2- atoms to form MnO6 octahedra that share corners with two equivalent MnO4 tetrahedra, corners with four CoO4 tetrahedra, an edgeedge with one MnO6 octahedra, and edges with five CoO6 octahedra. There are a spread of Mn–O bond distances ranging from 1.92–2.18 Å. In the fourth Mn2+ site, Mn2+ is bonded to six O2- atoms to form MnO6 octahedra that share corners with six CoO4 tetrahedra, edges with two MnO6 octahedra, and edges with four CoO6 octahedra. There are a spread of Mn–O bond distances ranging from 1.93–2.17 Å. There are eight inequivalent Co3+ sites. In the first Co3+ site, Co3+ is bonded to four O2- atoms to form CoO4 tetrahedra that share corners with six MnO6 octahedra and corners with six CoO6 octahedra. The corner-sharing octahedra tilt angles range from 53–65°. There are a spread of Co–O bond distances ranging from 1.94–2.00 Å. In the second Co3+ site, Co3+ is bonded to four O2- atoms to form CoO4 tetrahedra that share corners with three MnO6 octahedra and corners with nine CoO6 octahedra. The corner-sharing octahedra tilt angles range from 55–64°. There are a spread of Co–O bond distances ranging from 1.93–2.02 Å. In the third Co3+ site, Co3+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with two equivalent MnO4 tetrahedra, corners with four CoO4 tetrahedra, edges with three MnO6 octahedra, and edges with three CoO6 octahedra. There are a spread of Co–O bond distances ranging from 1.90–1.97 Å. In the fourth Co3+ site, Co3+ is bonded to six O2- atoms to form CoO6 octahedra that share a cornercorner with one MnO4 tetrahedra, corners with five CoO4 tetrahedra, edges with three MnO6 octahedra, and edges with three CoO6 octahedra. There are a spread of Co–O bond distances ranging from 1.94–1.97 Å. In the fifth Co3+ site, Co3+ is bonded to six O2- atoms to form CoO6 octahedra that share a cornercorner with one MnO4 tetrahedra, corners with five CoO4 tetrahedra, edges with three MnO6 octahedra, and edges with three CoO6 octahedra. There are a spread of Co–O bond distances ranging from 1.92–1.97 Å. In the sixth Co3+ site, Co3+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with two equivalent MnO4 tetrahedra, corners with four CoO4 tetrahedra, edges with three MnO6 octahedra, and edges with three CoO6 octahedra. There are a spread of Co–O bond distances ranging from 1.93–1.97 Å. In the seventh Co3+ site, Co3+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with three equivalent MnO4 tetrahedra, corners with three equivalent CoO4 tetrahedra, edges with two MnO6 octahedra, and edges with four CoO6 octahedra. There are a spread of Co–O bond distances ranging from 1.90–1.96 Å. In the eighth Co3+ site, Co3+ is bonded to four O2- atoms to form CoO4 tetrahedra that share corners with six MnO6 octahedra and corners with six CoO6 octahedra. The corner-sharing octahedra tilt angles range from 53–65°. There are a spread of Co–O bond distances ranging from 1.94–2.01 Å. There are sixteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mn2+ and three Co3+ atoms. In the second O2- site, O2- is bonded to one Mn2+ and three Co3+ atoms to form distorted corner-sharing OMnCo3 trigonal pyramids. In the third O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Mn2+ and two Co3+ atoms. In the fourth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Mn2+ and two Co3+ atoms. In the fifth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mn2+ and three Co3+ atoms. In the sixth O2- site, O2- is bonded to two Mn2+ and two Co3+ atoms to form distorted corner-sharing OMn2Co2 tetrahedra. In the seventh O2- site, O2- is bonded to one Mn2+ and three Co3+ atoms to form distorted OMnCo3 tetrahedra that share corners with two OMn2Co2 tetrahedra, a cornercorner with one OMnCo3 trigonal pyramid, and an edgeedge with one OMn2Co2 tetrahedra. In the eighth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mn2+ and three Co3+ atoms. In the ninth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mn2+ and three Co3+ atoms. In the tenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Co3+ atoms. In the eleventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mn2+ and three Co3+ atoms. In the twelfth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mn2+ and three Co3+ atoms. In the thirteenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Mn2+ and two Co3+ atoms. In the fourteenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Mn2+ and two Co3+ atoms. In the fifteenth O2- site, O2- is bonded to two Mn2+ and two Co3+ atoms to form distorted OMn2Co2 tetrahedra that share corners with two OMn2Co2 tetrahedra, a cornercorner with one OMnCo3 trigonal pyramid, and an edgeedge with one OMnCo3 tetrahedra. In the sixteenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Mn2+ and two Co3+ atoms.