CaFe2O4 crystallizes in the orthorhombic Pmn2_1 space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form distorted CaO6 pentagonal pyramids that share corners with six equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, and edges with four equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 4-20°. In the second Ca site, Ca(2) is bonded in a 6-coordinate geometry to two equivalent 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(1), one O(2), two equivalent O(3), and two equivalent O(4) atoms to form FeO6 octahedra that share corners with three equivalent Ca(1)O6 pentagonal pyramids, edges with two equivalent Fe(1)O6 octahedra, edges with four equivalent Fe(2)O6 octahedra, and  an edgeedge with one Ca(1)O6 pentagonal pyramid. In the second Fe site, Fe(2) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(2) atoms to form FeO6 octahedra that share edges with two equivalent Fe(2)O6 octahedra, edges with four equivalent Fe(1)O6 octahedra, and edges with two equivalent Ca(1)O6 pentagonal pyramids. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Ca(1), one Fe(1), and two equivalent Fe(2) atoms to form OCaFe3 trigonal pyramids that share corners with two equivalent O(3)Ca2Fe3 trigonal bipyramids, corners with two equivalent O(4)Ca2Fe3 trigonal bipyramids, corners with three equivalent O(1)CaFe3 trigonal pyramids, corners with three equivalent O(2)CaFe3 trigonal pyramids, edges with two equivalent O(3)Ca2Fe3 trigonal bipyramids, edges with two equivalent O(4)Ca2Fe3 trigonal bipyramids, and  an edgeedge with one O(2)CaFe3 trigonal pyramid. In the second O site, O(2) is bonded to one Ca(2), one Fe(1), and two equivalent Fe(2) atoms to form OCaFe3 trigonal pyramids that share corners with two equivalent O(3)Ca2Fe3 trigonal bipyramids, corners with two equivalent O(4)Ca2Fe3 trigonal bipyramids, corners with three equivalent O(1)CaFe3 trigonal pyramids, corners with three equivalent O(2)CaFe3 trigonal pyramids, edges with two equivalent O(3)Ca2Fe3 trigonal bipyramids, edges with two equivalent O(4)Ca2Fe3 trigonal bipyramids, and  an edgeedge with one O(1)CaFe3 trigonal pyramid. In the third O site, O(3) is bonded to one Ca(1), one Ca(2), one Fe(2), and two equivalent Fe(1) atoms to form OCa2Fe3 trigonal bipyramids that share corners with two equivalent O(3)Ca2Fe3 trigonal bipyramids, corners with three equivalent O(4)Ca2Fe3 trigonal bipyramids, corners with two equivalent O(1)CaFe3 trigonal pyramids, corners with two equivalent O(2)CaFe3 trigonal pyramids,  an edgeedge with one O(3)Ca2Fe3 trigonal bipyramid, edges with three equivalent O(4)Ca2Fe3 trigonal bipyramids, edges with two equivalent O(1)CaFe3 trigonal pyramids, and edges with two equivalent O(2)CaFe3 trigonal pyramids. In the fourth O site, O(4) is bonded to one Ca(1), one Ca(2), one Fe(2), and two equivalent Fe(1) atoms to form OCa2Fe3 trigonal bipyramids that share corners with two equivalent O(4)Ca2Fe3 trigonal bipyramids, corners with three equivalent O(3)Ca2Fe3 trigonal bipyramids, corners with two equivalent O(1)CaFe3 trigonal pyramids, corners with two equivalent O(2)CaFe3 trigonal pyramids,  an edgeedge with one O(4)Ca2Fe3 trigonal bipyramid, edges with three equivalent O(3)Ca2Fe3 trigonal bipyramids, edges with two equivalent O(1)CaFe3 trigonal pyramids, and edges with two equivalent O(2)CaFe3 trigonal pyramids.
CaFe2O4 crystallizes in the orthorhombic Pmn2_1 space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form distorted CaO6 pentagonal pyramids that share corners with six equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, and edges with four equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 4-20°. Both Ca(1)-O(1) bond lengths are 2.31 Å. Both Ca(1)-O(3) bond lengths are 2.40 Å. Both Ca(1)-O(4) bond lengths are 2.42 Å. In the second Ca site, Ca(2) is bonded in a 6-coordinate geometry to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. Both Ca(2)-O(2) bond lengths are 2.33 Å. Both Ca(2)-O(3) bond lengths are 2.40 Å. Both Ca(2)-O(4) bond lengths are 2.42 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(2), two equivalent O(3), and two equivalent O(4) atoms to form FeO6 octahedra that share corners with three equivalent Ca(1)O6 pentagonal pyramids, edges with two equivalent Fe(1)O6 octahedra, edges with four equivalent Fe(2)O6 octahedra, and  an edgeedge with one Ca(1)O6 pentagonal pyramid. The Fe(1)-O(1) bond length is 1.94 Å. The Fe(1)-O(2) bond length is 2.03 Å. There is one shorter (1.96 Å) and one longer (2.21 Å) Fe(1)-O(3) bond length. There is one shorter (2.00 Å) and one longer (2.13 Å) Fe(1)-O(4) bond length. In the second Fe site, Fe(2) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(2) atoms to form FeO6 octahedra that share edges with two equivalent Fe(2)O6 octahedra, edges with four equivalent Fe(1)O6 octahedra, and edges with two equivalent Ca(1)O6 pentagonal pyramids. The Fe(2)-O(3) bond length is 2.07 Å. The Fe(2)-O(4) bond length is 2.07 Å. There is one shorter (1.99 Å) and one longer (2.04 Å) Fe(2)-O(1) bond length. There is one shorter (2.00 Å) and one longer (2.02 Å) Fe(2)-O(2) bond length. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Ca(1), one Fe(1), and two equivalent Fe(2) atoms to form OCaFe3 trigonal pyramids that share corners with two equivalent O(3)Ca2Fe3 trigonal bipyramids, corners with two equivalent O(4)Ca2Fe3 trigonal bipyramids, corners with three equivalent O(1)CaFe3 trigonal pyramids, corners with three equivalent O(2)CaFe3 trigonal pyramids, edges with two equivalent O(3)Ca2Fe3 trigonal bipyramids, edges with two equivalent O(4)Ca2Fe3 trigonal bipyramids, and  an edgeedge with one O(2)CaFe3 trigonal pyramid. In the second O site, O(2) is bonded to one Ca(2), one Fe(1), and two equivalent Fe(2) atoms to form OCaFe3 trigonal pyramids that share corners with two equivalent O(3)Ca2Fe3 trigonal bipyramids, corners with two equivalent O(4)Ca2Fe3 trigonal bipyramids, corners with three equivalent O(1)CaFe3 trigonal pyramids, corners with three equivalent O(2)CaFe3 trigonal pyramids, edges with two equivalent O(3)Ca2Fe3 trigonal bipyramids, edges with two equivalent O(4)Ca2Fe3 trigonal bipyramids, and  an edgeedge with one O(1)CaFe3 trigonal pyramid. In the third O site, O(3) is bonded to one Ca(1), one Ca(2), one Fe(2), and two equivalent Fe(1) atoms to form OCa2Fe3 trigonal bipyramids that share corners with two equivalent O(3)Ca2Fe3 trigonal bipyramids, corners with three equivalent O(4)Ca2Fe3 trigonal bipyramids, corners with two equivalent O(1)CaFe3 trigonal pyramids, corners with two equivalent O(2)CaFe3 trigonal pyramids,  an edgeedge with one O(3)Ca2Fe3 trigonal bipyramid, edges with three equivalent O(4)Ca2Fe3 trigonal bipyramids, edges with two equivalent O(1)CaFe3 trigonal pyramids, and edges with two equivalent O(2)CaFe3 trigonal pyramids. In the fourth O site, O(4) is bonded to one Ca(1), one Ca(2), one Fe(2), and two equivalent Fe(1) atoms to form OCa2Fe3 trigonal bipyramids that share corners with two equivalent O(4)Ca2Fe3 trigonal bipyramids, corners with three equivalent O(3)Ca2Fe3 trigonal bipyramids, corners with two equivalent O(1)CaFe3 trigonal pyramids, corners with two equivalent O(2)CaFe3 trigonal pyramids,  an edgeedge with one O(4)Ca2Fe3 trigonal bipyramid, edges with three equivalent O(3)Ca2Fe3 trigonal bipyramids, edges with two equivalent O(1)CaFe3 trigonal pyramids, and edges with two equivalent O(2)CaFe3 trigonal pyramids.