CaCr3O7 crystallizes in the orthorhombic Pnma space group. Ca(1) is bonded in a 7-coordinate geometry to one O(3), two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(4), two equivalent O(1), and two equivalent O(2) atoms to form distorted edge-sharing CrO5 trigonal bipyramids. In the second Cr site, Cr(2) is bonded in a 5-coordinate geometry to one O(3), two equivalent O(1), and two equivalent O(2) atoms. There are four inequivalent O sites. In the first O site, O(3) is bonded in a distorted bent 120 degrees geometry to one Ca(1) and one Cr(2) atom. In the second O site, O(4) is bonded in a bent 150 degrees geometry to one Ca(1) and one Cr(1) atom. In the third O site, O(1) is bonded in a 4-coordinate geometry to one Ca(1), one Cr(2), and two equivalent Cr(1) atoms. In the fourth O site, O(2) is bonded in a 4-coordinate geometry to one Ca(1), one Cr(2), and two equivalent Cr(1) atoms.
CaCr3O7 crystallizes in the orthorhombic Pnma space group. Ca(1) is bonded in a 7-coordinate geometry to one O(3), two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms. The Ca(1)-O(3) bond length is 2.35 Å. Both Ca(1)-O(1) bond lengths are 2.54 Å. Both Ca(1)-O(2) bond lengths are 2.57 Å. Both Ca(1)-O(4) bond lengths are 2.31 Å. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(4), two equivalent O(1), and two equivalent O(2) atoms to form distorted edge-sharing CrO5 trigonal bipyramids. The Cr(1)-O(4) bond length is 1.67 Å. There is one shorter (1.94 Å) and one longer (1.95 Å) Cr(1)-O(1) bond length. There is one shorter (1.97 Å) and one longer (1.98 Å) Cr(1)-O(2) bond length. In the second Cr site, Cr(2) is bonded in a 5-coordinate geometry to one O(3), two equivalent O(1), and two equivalent O(2) atoms. The Cr(2)-O(3) bond length is 1.71 Å. Both Cr(2)-O(1) bond lengths are 2.01 Å. Both Cr(2)-O(2) bond lengths are 1.96 Å. There are four inequivalent O sites. In the first O site, O(3) is bonded in a distorted bent 120 degrees geometry to one Ca(1) and one Cr(2) atom. In the second O site, O(4) is bonded in a bent 150 degrees geometry to one Ca(1) and one Cr(1) atom. In the third O site, O(1) is bonded in a 4-coordinate geometry to one Ca(1), one Cr(2), and two equivalent Cr(1) atoms. In the fourth O site, O(2) is bonded in a 4-coordinate geometry to one Ca(1), one Cr(2), and two equivalent Cr(1) atoms.