Materials Data on Al2CoO4 by Materials Project
CoAl2O4 is Spinel-like structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are six inequivalent Co2+ sites. In the first Co2+ site, Co2+ is bonded to four O2- atoms to form CoO4 tetrahedra that share corners with three equivalent CoO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 55–64°. There are a spread of Co–O bond distances ranging from 1.93–2.00 Å. In the second Co2+ site, Co2+ is bonded to four O2- atoms to form CoO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 59–60°. There is one shorter (1.97 Å) and three longer (1.98 Å) Co–O bond length. In the third Co2+ site, Co2+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with three equivalent CoO4 tetrahedra, corners with three equivalent AlO4 tetrahedra, and edges with six AlO6 octahedra. There are a spread of Co–O bond distances ranging from 1.98–2.18 Å. In the fourth Co2+ site, Co2+ is bonded to four O2- atoms to form CoO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 59–62°. There are three shorter (1.98 Å) and one longer (2.02 Å) Co–O bond lengths. In the fifth Co2+ site, Co2+ is bonded to four O2- atoms to form CoO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 58–60°. There is one shorter (1.95 Å) and three longer (1.97 Å) Co–O bond length. In the sixth Co2+ site, Co2+ is bonded to four O2- atoms to form CoO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 59–61°. There is three shorter (1.99 Å) and one longer (2.00 Å) Co–O bond length. There are twelve inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with three equivalent CoO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 53–62°. There is one shorter (1.81 Å) and three longer (1.83 Å) Al–O bond length. In the second Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two equivalent AlO4 tetrahedra, corners with four CoO4 tetrahedra, an edgeedge with one CoO6 octahedra, and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.91–1.98 Å. In the third Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two equivalent AlO4 tetrahedra, corners with four CoO4 tetrahedra, an edgeedge with one CoO6 octahedra, and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.91–1.98 Å. In the fourth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two equivalent AlO4 tetrahedra, corners with four CoO4 tetrahedra, an edgeedge with one CoO6 octahedra, and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.91–1.98 Å. In the fifth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six CoO4 tetrahedra and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.92–1.94 Å. In the sixth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six CoO4 tetrahedra and edges with six AlO6 octahedra. There is two shorter (1.92 Å) and four longer (1.93 Å) Al–O bond length. In the seventh Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six CoO4 tetrahedra and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.92–1.94 Å. In the eighth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six CoO4 tetrahedra and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.92–1.94 Å. In the ninth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share a cornercorner with one AlO4 tetrahedra, corners with five CoO4 tetrahedra, an edgeedge with one CoO6 octahedra, and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.87–2.04 Å. In the tenth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six CoO4 tetrahedra and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.92–1.94 Å. In the eleventh Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share a cornercorner with one AlO4 tetrahedra, corners with five CoO4 tetrahedra, an edgeedge with one CoO6 octahedra, and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.89–2.05 Å. In the twelfth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share a cornercorner with one AlO4 tetrahedra, corners with five CoO4 tetrahedra, an edgeedge with one CoO6 octahedra, and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.87–2.04 Å. There are twenty-three inequivalent O2- sites. In the first O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Co2+ and three Al3+ atoms. In the second O2- site, O2- is bonded to one Co2+ and three Al3+ atoms to form distorted corner-sharing OAl3Co tetrahedra. In the third O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Co2+ and three Al3+ atoms. In the fourth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Co2+ and three Al3+ atoms. In the fifth O2- site, O2- is bonded to one Co2+ and three Al3+ atoms to form a mixture of distorted corner and edge-sharing OAl3Co trigonal pyramids. In the sixth O2- site, O2- is bonded to one Co2+ and three Al3+ atoms to form a mixture of distorted corner and edge-sharing OAl3Co trigonal pyramids. In the seventh O2- site, O2- is bonded to one Co2+ and three Al3+ atoms to form a mixture of distorted corner and edge-sharing OAl3Co trigonal pyramids. In the eighth O2- site, O2- is bonded to one Co2+ and three Al3+ atoms to form a mixture of distorted corner and edge-sharing OAl3Co tetrahedra. In the ninth O2- site, O2- is bonded to one Co2+ and three Al3+ atoms to form a mixture of distorted corner and edge-sharing OAl3Co trigonal pyramids. In the tenth O2- site, O2- is bonded to one Co2+ and three Al3+ atoms to form a mixture of distorted corner and edge-sharing OAl3Co trigonal pyramids. In the eleventh O2- site, O2- is bonded to one Co2+ and three Al3+ atoms to form a mixture of distorted corner and edge-sharing OAl3Co trigonal pyramids. In the twelfth O2- site, O2- is bonded to one Co2+ and three Al3+ atoms to form a mixture of distorted corner and edge-sharing OAl3Co tetrahedra. In the thirteenth O2- site, O2- is bonded to one Co2+ and three Al3+ atoms to form a mixture of distorted corner and edge-sharing OAl3Co tetrahedra. In the fourteenth O2- site, O2- is bonded to one Co2+ and three Al3+ atoms to form a mixture of distorted corner and edge-sharing OAl3Co tetrahedra. In the fifteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the sixteenth O2- site, O2- is bonded to one Co2+ and three Al3+ atoms to form a mixture of distorted corner and edge-sharing OAl3Co trigonal pyramids. In the seventeenth O2- site, O2- is bonded to one Co2+ and three Al3+ atoms to form a mixture of distorted corner and edge-sharing OAl3Co tetrahedra. In the eighteenth O2- site, O2- is bonded to one Co2+ and three Al3+ atoms to form a mixture of distorted corner and edge-sharing OAl3Co tetrahedra. In the nineteenth O2- site, O2- is bonded to one Co2+ and three Al3+ atoms to form a mixture of distorted corner and edge-sharing OAl3Co tetrahedra. In the twentieth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Co2+ and two Al3+ atoms. In the twenty-first O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Co2+ and two Al3+ atoms. In the twenty-second O2- site, O2- is bonded to one Co2+ and three Al3+ atoms to form distorted corner-sharing OAl3Co trigonal pyramids. In the twenty-third O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Co2+ and two Al3+ atoms.