CaCr2O4 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 Cr sites. In the first Cr site, Cr(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 CrO6 octahedra. The corner-sharing octahedral tilt angles range from 51-61°. In the second Cr site, Cr(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 CrO6 octahedra. The corner-sharing octahedral tilt angles range from 51-61°. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Ca(1), one Cr(2), and two equivalent Cr(1) atoms to form OCaCr3 trigonal pyramids that share  a cornercorner with one O(4)Ca2Cr3 square pyramid, corners with two equivalent O(3)Ca2Cr3 square pyramids, corners with two equivalent O(1)CaCr3 trigonal pyramids, edges with two equivalent O(4)Ca2Cr3 square pyramids, and edges with three equivalent O(3)Ca2Cr3 square pyramids. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Ca(1), one Cr(1), and two equivalent Cr(2) atoms. In the third O site, O(3) is bonded to two equivalent Ca(1) and three equivalent Cr(1) atoms to form OCa2Cr3 square pyramids that share corners with two equivalent O(4)Ca2Cr3 square pyramids, corners with two equivalent O(1)CaCr3 trigonal pyramids,  an edgeedge with one O(4)Ca2Cr3 square pyramid, edges with four equivalent O(3)Ca2Cr3 square pyramids, and edges with three equivalent O(1)CaCr3 trigonal pyramids. In the fourth O site, O(4) is bonded to two equivalent Ca(1) and three equivalent Cr(2) atoms to form distorted OCa2Cr3 square pyramids that share corners with two equivalent O(3)Ca2Cr3 square pyramids,  a cornercorner with one O(1)CaCr3 trigonal pyramid,  an edgeedge with one O(3)Ca2Cr3 square pyramid, edges with four equivalent O(4)Ca2Cr3 square pyramids, and edges with two equivalent O(1)CaCr3 trigonal pyramids.
CaCr2O4 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 2.38 Å. The Ca(1)-O(2) bond length is 2.56 Å. Both Ca(1)-O(3) bond lengths are 2.31 Å. Both Ca(1)-O(4) bond lengths are 2.24 Å. There are two inequivalent Cr sites. In the first Cr site, Cr(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 CrO6 octahedra. The corner-sharing octahedral tilt angles range from 51-61°. The Cr(1)-O(2) bond length is 1.98 Å. Both Cr(1)-O(1) bond lengths are 2.00 Å. There are two shorter (2.12 Å) and one longer (2.20 Å) Cr(1)-O(3) bond length. In the second Cr site, Cr(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 CrO6 octahedra. The corner-sharing octahedral tilt angles range from 51-61°. The Cr(2)-O(1) bond length is 2.08 Å. Both Cr(2)-O(2) bond lengths are 2.03 Å. There is one shorter (2.00 Å) and two longer (2.09 Å) Cr(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 Cr(2), and two equivalent Cr(1) atoms to form OCaCr3 trigonal pyramids that share  a cornercorner with one O(4)Ca2Cr3 square pyramid, corners with two equivalent O(3)Ca2Cr3 square pyramids, corners with two equivalent O(1)CaCr3 trigonal pyramids, edges with two equivalent O(4)Ca2Cr3 square pyramids, and edges with three equivalent O(3)Ca2Cr3 square pyramids. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Ca(1), one Cr(1), and two equivalent Cr(2) atoms. In the third O site, O(3) is bonded to two equivalent Ca(1) and three equivalent Cr(1) atoms to form OCa2Cr3 square pyramids that share corners with two equivalent O(4)Ca2Cr3 square pyramids, corners with two equivalent O(1)CaCr3 trigonal pyramids,  an edgeedge with one O(4)Ca2Cr3 square pyramid, edges with four equivalent O(3)Ca2Cr3 square pyramids, and edges with three equivalent O(1)CaCr3 trigonal pyramids. In the fourth O site, O(4) is bonded to two equivalent Ca(1) and three equivalent Cr(2) atoms to form distorted OCa2Cr3 square pyramids that share corners with two equivalent O(3)Ca2Cr3 square pyramids,  a cornercorner with one O(1)CaCr3 trigonal pyramid,  an edgeedge with one O(3)Ca2Cr3 square pyramid, edges with four equivalent O(4)Ca2Cr3 square pyramids, and edges with two equivalent O(1)CaCr3 trigonal pyramids.