Materials Data on Ca2AlCoO5 by Materials Project
Ca2CoAlO5 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are four inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.29–2.86 Å. In the second Ca2+ site, Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.33–2.92 Å. In the third Ca2+ site, Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.29–2.87 Å. In the fourth Ca2+ site, Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.32–2.93 Å. There are two inequivalent Co3+ sites. In the first Co3+ site, Co3+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with four equivalent CoO6 octahedra and corners with two AlO4 tetrahedra. The corner-sharing octahedral tilt angles are 12°. There are four shorter (1.94 Å) and two longer (2.17 Å) Co–O bond lengths. In the second Co3+ site, Co3+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with four equivalent CoO6 octahedra and corners with two AlO4 tetrahedra. The corner-sharing octahedral tilt angles are 12°. There are a spread of Co–O bond distances ranging from 1.91–2.25 Å. There are two inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with two CoO6 octahedra and corners with two equivalent AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 40–43°. There are a spread of Al–O bond distances ranging from 1.75–1.81 Å. In the second Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with two CoO6 octahedra and corners with two equivalent AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 40–43°. There are a spread of Al–O bond distances ranging from 1.75–1.81 Å. There are ten inequivalent O2- sites. In the first O2- site, O2- is bonded to two Ca2+ and two Al3+ atoms to form distorted OCa2Al2 tetrahedra that share corners with six OCa4Co2 octahedra and corners with two equivalent OCa2Al2 tetrahedra. The corner-sharing octahedra tilt angles range from 16–85°. In the second O2- site, O2- is bonded to two Ca2+ and two Al3+ atoms to form distorted OCa2Al2 tetrahedra that share corners with six OCa4Co2 octahedra and corners with two equivalent OCa2Al2 tetrahedra. The corner-sharing octahedra tilt angles range from 15–85°. In the third O2- site, O2- is bonded in a 1-coordinate geometry to three Ca2+, one Co3+, and one Al3+ atom. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to three Ca2+, one Co3+, and one Al3+ atom. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to three Ca2+, one Co3+, and one Al3+ atom. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to three Ca2+, one Co3+, and one Al3+ atom. In the seventh O2- site, O2- is bonded to four Ca2+ and two Co3+ atoms to form distorted OCa4Co2 octahedra that share corners with two equivalent OCa4Co2 octahedra, corners with four OCa2Al2 tetrahedra, edges with two equivalent OCa4Co2 octahedra, and faces with two equivalent OCa4Co2 octahedra. The corner-sharing octahedra tilt angles range from 1–2°. In the eighth O2- site, O2- is bonded in a 6-coordinate geometry to four Ca2+ and two Co3+ atoms. In the ninth O2- site, O2- is bonded to four Ca2+ and two Co3+ atoms to form distorted OCa4Co2 octahedra that share corners with two equivalent OCa4Co2 octahedra, corners with four OCa2Al2 tetrahedra, edges with two equivalent OCa4Co2 octahedra, and faces with two equivalent OCa4Co2 octahedra. The corner-sharing octahedra tilt angles range from 1–2°. In the tenth O2- site, O2- is bonded to four Ca2+ and two Co3+ atoms to form distorted OCa4Co2 octahedra that share corners with four OCa2Al2 tetrahedra and faces with four OCa4Co2 octahedra.