MgAlCrO4 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(1), one O(3), and two equivalent O(2) atoms to form distorted MgO4 tetrahedra that share corners with four equivalent Al(1)O6 octahedra, corners with two equivalent Mg(1)O4 tetrahedra, and  an edgeedge with one Al(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-62°. Cr(1) is bonded in a 5-coordinate geometry to one O(4), two equivalent O(1), and two equivalent O(3) atoms. Al(1) is bonded to one O(1), one O(3), two equivalent O(2), and two equivalent O(4) atoms to form AlO6 octahedra that share corners with four equivalent Mg(1)O4 tetrahedra, edges with two equivalent Al(1)O6 octahedra, and  an edgeedge with one Mg(1)O4 tetrahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Mg(1), two equivalent Cr(1), and one Al(1) atom. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to two equivalent Mg(1) and two equivalent Al(1) atoms. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to one Mg(1), two equivalent Cr(1), and one Al(1) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Cr(1) and two equivalent Al(1) atoms.
MgAlCrO4 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(1), one O(3), and two equivalent O(2) atoms to form distorted MgO4 tetrahedra that share corners with four equivalent Al(1)O6 octahedra, corners with two equivalent Mg(1)O4 tetrahedra, and  an edgeedge with one Al(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-62°. The Mg(1)-O(1) bond length is 2.05 Å. The Mg(1)-O(3) bond length is 2.06 Å. Both Mg(1)-O(2) bond lengths are 1.93 Å. Cr(1) is bonded in a 5-coordinate geometry to one O(4), two equivalent O(1), and two equivalent O(3) atoms. The Cr(1)-O(4) bond length is 1.93 Å. There is one shorter (1.99 Å) and one longer (2.07 Å) Cr(1)-O(1) bond length. There is one shorter (2.01 Å) and one longer (2.05 Å) Cr(1)-O(3) bond length. Al(1) is bonded to one O(1), one O(3), two equivalent O(2), and two equivalent O(4) atoms to form AlO6 octahedra that share corners with four equivalent Mg(1)O4 tetrahedra, edges with two equivalent Al(1)O6 octahedra, and  an edgeedge with one Mg(1)O4 tetrahedra. The Al(1)-O(1) bond length is 1.93 Å. The Al(1)-O(3) bond length is 1.93 Å. There is one shorter (2.03 Å) and one longer (2.04 Å) Al(1)-O(2) bond length. There is one shorter (1.89 Å) and one longer (1.91 Å) Al(1)-O(4) bond length. There are four inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Mg(1), two equivalent Cr(1), and one Al(1) atom. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to two equivalent Mg(1) and two equivalent Al(1) atoms. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to one Mg(1), two equivalent Cr(1), and one Al(1) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Cr(1) and two equivalent Al(1) atoms.