Cr3MnO8 is Rutile-derived structured and crystallizes in the orthorhombic Cmc2_1 space group. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form CrO6 octahedra that share corners with two equivalent Mn(1)O6 octahedra,  an edgeedge with one Mn(1)O6 octahedra, edges with two equivalent Cr(1)O6 octahedra, and edges with two equivalent Cr(2)O6 octahedra. The corner-sharing octahedral tilt angles are 50°. In the second Cr site, Cr(2) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(5) atoms to form CrO6 octahedra that share corners with two equivalent Mn(1)O6 octahedra,  an edgeedge with one Mn(1)O6 octahedra, and edges with four equivalent Cr(1)O6 octahedra. The corner-sharing octahedral tilt angles are 52°. Mn(1) is bonded to one O(2), one O(6), two equivalent O(1), and two equivalent O(5) atoms to form MnO6 octahedra that share corners with two equivalent Cr(2)O6 octahedra, corners with four equivalent Cr(1)O6 octahedra,  an edgeedge with one Cr(2)O6 octahedra, and edges with two equivalent Cr(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 50-52°. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Cr(1), one Cr(2), and one Mn(1) atom. In the second O site, O(2) is bonded in a distorted trigonal non-coplanar geometry to two equivalent Cr(1) and one Mn(1) atom. In the third O site, O(3) is bonded in a distorted T-shaped geometry to one Cr(2) and two equivalent Cr(1) atoms. In the fourth O site, O(4) is bonded in a distorted trigonal non-coplanar geometry to one Cr(2) and two equivalent Cr(1) atoms. In the fifth O site, O(5) is bonded in a distorted trigonal non-coplanar geometry to one Cr(1), one Cr(2), and one Mn(1) atom. In the sixth O site, O(6) is bonded in a trigonal planar geometry to two equivalent Cr(1) and one Mn(1) atom.
Cr3MnO8 is Rutile-derived structured and crystallizes in the orthorhombic Cmc2_1 space group. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form CrO6 octahedra that share corners with two equivalent Mn(1)O6 octahedra,  an edgeedge with one Mn(1)O6 octahedra, edges with two equivalent Cr(1)O6 octahedra, and edges with two equivalent Cr(2)O6 octahedra. The corner-sharing octahedral tilt angles are 50°. The Cr(1)-O(1) bond length is 1.85 Å. The Cr(1)-O(2) bond length is 1.98 Å. The Cr(1)-O(3) bond length is 1.97 Å. The Cr(1)-O(4) bond length is 1.96 Å. The Cr(1)-O(5) bond length is 2.01 Å. The Cr(1)-O(6) bond length is 1.92 Å. In the second Cr site, Cr(2) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(5) atoms to form CrO6 octahedra that share corners with two equivalent Mn(1)O6 octahedra,  an edgeedge with one Mn(1)O6 octahedra, and edges with four equivalent Cr(1)O6 octahedra. The corner-sharing octahedral tilt angles are 52°. The Cr(2)-O(3) bond length is 1.90 Å. The Cr(2)-O(4) bond length is 1.87 Å. Both Cr(2)-O(1) bond lengths are 2.04 Å. Both Cr(2)-O(5) bond lengths are 1.92 Å. Mn(1) is bonded to one O(2), one O(6), two equivalent O(1), and two equivalent O(5) atoms to form MnO6 octahedra that share corners with two equivalent Cr(2)O6 octahedra, corners with four equivalent Cr(1)O6 octahedra,  an edgeedge with one Cr(2)O6 octahedra, and edges with two equivalent Cr(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 50-52°. The Mn(1)-O(2) bond length is 1.91 Å. The Mn(1)-O(6) bond length is 2.00 Å. Both Mn(1)-O(1) bond lengths are 1.97 Å. Both Mn(1)-O(5) bond lengths are 1.92 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Cr(1), one Cr(2), and one Mn(1) atom. In the second O site, O(2) is bonded in a distorted trigonal non-coplanar geometry to two equivalent Cr(1) and one Mn(1) atom. In the third O site, O(3) is bonded in a distorted T-shaped geometry to one Cr(2) and two equivalent Cr(1) atoms. In the fourth O site, O(4) is bonded in a distorted trigonal non-coplanar geometry to one Cr(2) and two equivalent Cr(1) atoms. In the fifth O site, O(5) is bonded in a distorted trigonal non-coplanar geometry to one Cr(1), one Cr(2), and one Mn(1) atom. In the sixth O site, O(6) is bonded in a trigonal planar geometry to two equivalent Cr(1) and one Mn(1) atom.