CaFe2O4 crystallizes in the monoclinic C2/m space group. Ca(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), two equivalent O(3), and two equivalent O(4) atoms. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(2), two equivalent O(1), and three equivalent O(3) atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 51-62°. In the second Fe site, Fe(2) is bonded to one O(1), two equivalent O(2), and three equivalent O(4) atoms to form a mixture of distorted corner and edge-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 51-62°. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Ca(1), one Fe(2), and two equivalent Fe(1) atoms to form OCaFe3 trigonal pyramids that share  a cornercorner with one O(4)Ca2Fe3 square pyramid, corners with two equivalent O(3)Ca2Fe3 square pyramids, corners with two equivalent O(1)CaFe3 trigonal pyramids, edges with two equivalent O(4)Ca2Fe3 square pyramids, and edges with three equivalent O(3)Ca2Fe3 square pyramids. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to one Ca(1), one Fe(1), and two equivalent Fe(2) atoms. In the third O site, O(3) is bonded to two equivalent Ca(1) and three equivalent Fe(1) atoms to form OCa2Fe3 square pyramids that share corners with two equivalent O(4)Ca2Fe3 square pyramids, corners with two equivalent O(1)CaFe3 trigonal pyramids,  an edgeedge with one O(4)Ca2Fe3 square pyramid, edges with four equivalent O(3)Ca2Fe3 square pyramids, and edges with three equivalent O(1)CaFe3 trigonal pyramids. In the fourth O site, O(4) is bonded to two equivalent Ca(1) and three equivalent Fe(2) atoms to form distorted OCa2Fe3 square pyramids that share corners with two equivalent O(3)Ca2Fe3 square pyramids,  a cornercorner with one O(1)CaFe3 trigonal pyramid,  an edgeedge with one O(3)Ca2Fe3 square pyramid, edges with four equivalent O(4)Ca2Fe3 square pyramids, and edges with two equivalent O(1)CaFe3 trigonal pyramids.
CaFe2O4 crystallizes in the monoclinic C2/m space group. Ca(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), two equivalent O(3), and two equivalent O(4) atoms. The Ca(1)-O(1) bond length is 2.43 Å. The Ca(1)-O(2) bond length is 2.53 Å. Both Ca(1)-O(3) bond lengths are 2.31 Å. Both Ca(1)-O(4) bond lengths are 2.25 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(2), two equivalent O(1), and three equivalent O(3) atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 51-62°. The Fe(1)-O(2) bond length is 2.00 Å. Both Fe(1)-O(1) bond lengths are 2.02 Å. There are two shorter (2.13 Å) and one longer (2.43 Å) Fe(1)-O(3) bond length. In the second Fe site, Fe(2) is bonded to one O(1), two equivalent O(2), and three equivalent O(4) atoms to form a mixture of distorted corner and edge-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 51-62°. The Fe(2)-O(1) bond length is 2.07 Å. Both Fe(2)-O(2) bond lengths are 2.04 Å. There is one shorter (2.03 Å) and two longer (2.15 Å) Fe(2)-O(4) bond lengths. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Ca(1), one Fe(2), and two equivalent Fe(1) atoms to form OCaFe3 trigonal pyramids that share  a cornercorner with one O(4)Ca2Fe3 square pyramid, corners with two equivalent O(3)Ca2Fe3 square pyramids, corners with two equivalent O(1)CaFe3 trigonal pyramids, edges with two equivalent O(4)Ca2Fe3 square pyramids, and edges with three equivalent O(3)Ca2Fe3 square pyramids. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to one Ca(1), one Fe(1), and two equivalent Fe(2) atoms. In the third O site, O(3) is bonded to two equivalent Ca(1) and three equivalent Fe(1) atoms to form OCa2Fe3 square pyramids that share corners with two equivalent O(4)Ca2Fe3 square pyramids, corners with two equivalent O(1)CaFe3 trigonal pyramids,  an edgeedge with one O(4)Ca2Fe3 square pyramid, edges with four equivalent O(3)Ca2Fe3 square pyramids, and edges with three equivalent O(1)CaFe3 trigonal pyramids. In the fourth O site, O(4) is bonded to two equivalent Ca(1) and three equivalent Fe(2) atoms to form distorted OCa2Fe3 square pyramids that share corners with two equivalent O(3)Ca2Fe3 square pyramids,  a cornercorner with one O(1)CaFe3 trigonal pyramid,  an edgeedge with one O(3)Ca2Fe3 square pyramid, edges with four equivalent O(4)Ca2Fe3 square pyramids, and edges with two equivalent O(1)CaFe3 trigonal pyramids.