CaFe2O4 is Spinel structured and crystallizes in the triclinic P-1 space group. Ca(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form CaO4 tetrahedra that share corners with three equivalent Fe(1)O6 octahedra, corners with three equivalent Fe(2)O6 octahedra, corners with three equivalent Fe(3)O6 octahedra, and corners with three equivalent Fe(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 56-64°. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form FeO6 octahedra that share corners with six equivalent Ca(1)O4 tetrahedra, edges with two equivalent Fe(2)O6 octahedra, edges with two equivalent Fe(3)O6 octahedra, and edges with two equivalent Fe(4)O6 octahedra. In the second Fe site, Fe(2) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form FeO6 octahedra that share corners with six equivalent Ca(1)O4 tetrahedra, edges with two equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(3)O6 octahedra, and edges with two equivalent Fe(4)O6 octahedra. In the third Fe site, Fe(3) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form FeO6 octahedra that share corners with six equivalent Ca(1)O4 tetrahedra, edges with two equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(2)O6 octahedra, and edges with two equivalent Fe(4)O6 octahedra. In the fourth Fe site, Fe(4) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form FeO6 octahedra that share corners with six equivalent Ca(1)O4 tetrahedra, edges with two equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(2)O6 octahedra, and edges with two equivalent Fe(3)O6 octahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Ca(1), one Fe(1), one Fe(3), and one Fe(4) atom to form a mixture of corner and edge-sharing OCaFe3 tetrahedra. In the second O site, O(2) is bonded to one Ca(1), one Fe(1), one Fe(2), and one Fe(4) atom to form a mixture of distorted corner and edge-sharing OCaFe3 tetrahedra. In the third O site, O(3) is bonded to one Ca(1), one Fe(1), one Fe(2), and one Fe(3) atom to form a mixture of distorted corner and edge-sharing OCaFe3 tetrahedra. In the fourth O site, O(4) is bonded to one Ca(1), one Fe(2), one Fe(3), and one Fe(4) atom to form a mixture of corner and edge-sharing OCaFe3 tetrahedra.
CaFe2O4 is Spinel structured and crystallizes in the triclinic P-1 space group. Ca(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form CaO4 tetrahedra that share corners with three equivalent Fe(1)O6 octahedra, corners with three equivalent Fe(2)O6 octahedra, corners with three equivalent Fe(3)O6 octahedra, and corners with three equivalent Fe(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 56-64°. The Ca(1)-O(1) bond length is 2.20 Å. The Ca(1)-O(2) bond length is 2.18 Å. The Ca(1)-O(3) bond length is 2.18 Å. The Ca(1)-O(4) bond length is 2.20 Å. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form FeO6 octahedra that share corners with six equivalent Ca(1)O4 tetrahedra, edges with two equivalent Fe(2)O6 octahedra, edges with two equivalent Fe(3)O6 octahedra, and edges with two equivalent Fe(4)O6 octahedra. Both Fe(1)-O(1) bond lengths are 2.09 Å. Both Fe(1)-O(2) bond lengths are 2.09 Å. Both Fe(1)-O(3) bond lengths are 2.02 Å. In the second Fe site, Fe(2) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form FeO6 octahedra that share corners with six equivalent Ca(1)O4 tetrahedra, edges with two equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(3)O6 octahedra, and edges with two equivalent Fe(4)O6 octahedra. Both Fe(2)-O(2) bond lengths are 2.07 Å. Both Fe(2)-O(3) bond lengths are 2.05 Å. Both Fe(2)-O(4) bond lengths are 2.08 Å. In the third Fe site, Fe(3) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form FeO6 octahedra that share corners with six equivalent Ca(1)O4 tetrahedra, edges with two equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(2)O6 octahedra, and edges with two equivalent Fe(4)O6 octahedra. Both Fe(3)-O(1) bond lengths are 1.99 Å. Both Fe(3)-O(3) bond lengths are 2.18 Å. Both Fe(3)-O(4) bond lengths are 2.01 Å. In the fourth Fe site, Fe(4) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form FeO6 octahedra that share corners with six equivalent Ca(1)O4 tetrahedra, edges with two equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(2)O6 octahedra, and edges with two equivalent Fe(3)O6 octahedra. Both Fe(4)-O(1) bond lengths are 2.09 Å. Both Fe(4)-O(2) bond lengths are 2.04 Å. Both Fe(4)-O(4) bond lengths are 2.08 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Ca(1), one Fe(1), one Fe(3), and one Fe(4) atom to form a mixture of corner and edge-sharing OCaFe3 tetrahedra. In the second O site, O(2) is bonded to one Ca(1), one Fe(1), one Fe(2), and one Fe(4) atom to form a mixture of distorted corner and edge-sharing OCaFe3 tetrahedra. In the third O site, O(3) is bonded to one Ca(1), one Fe(1), one Fe(2), and one Fe(3) atom to form a mixture of distorted corner and edge-sharing OCaFe3 tetrahedra. In the fourth O site, O(4) is bonded to one Ca(1), one Fe(2), one Fe(3), and one Fe(4) atom to form a mixture of corner and edge-sharing OCaFe3 tetrahedra.