MgCr2O6 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(1), one O(2), one O(3), and one O(5) atom to form MgO4 tetrahedra that share corners with two equivalent Cr(1)O4 tetrahedra and corners with three equivalent Cr(2)O4 tetrahedra. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(1), one O(3), one O(4), and one O(6) atom to form CrO4 tetrahedra that share corners with two equivalent Mg(1)O4 tetrahedra and corners with two equivalent Cr(2)O4 tetrahedra. In the second Cr site, Cr(2) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form CrO4 tetrahedra that share corners with two equivalent Cr(1)O4 tetrahedra and corners with three equivalent Mg(1)O4 tetrahedra. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to one Mg(1) and one Cr(1) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Mg(1) and one Cr(2) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Mg(1), one Cr(1), and one Cr(2) atom. In the fourth O site, O(4) is bonded in a distorted bent 150 degrees geometry to one Cr(1) and one Cr(2) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Mg(1) and one Cr(2) atom. In the sixth O site, O(6) is bonded in a single-bond geometry to one Cr(1) atom.
MgCr2O6 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(1), one O(2), one O(3), and one O(5) atom to form MgO4 tetrahedra that share corners with two equivalent Cr(1)O4 tetrahedra and corners with three equivalent Cr(2)O4 tetrahedra. The Mg(1)-O(1) bond length is 1.98 Å. The Mg(1)-O(2) bond length is 1.99 Å. The Mg(1)-O(3) bond length is 2.00 Å. The Mg(1)-O(5) bond length is 1.96 Å. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(1), one O(3), one O(4), and one O(6) atom to form CrO4 tetrahedra that share corners with two equivalent Mg(1)O4 tetrahedra and corners with two equivalent Cr(2)O4 tetrahedra. The Cr(1)-O(1) bond length is 1.67 Å. The Cr(1)-O(3) bond length is 1.89 Å. The Cr(1)-O(4) bond length is 1.82 Å. The Cr(1)-O(6) bond length is 1.61 Å. In the second Cr site, Cr(2) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form CrO4 tetrahedra that share corners with two equivalent Cr(1)O4 tetrahedra and corners with three equivalent Mg(1)O4 tetrahedra. The Cr(2)-O(2) bond length is 1.66 Å. The Cr(2)-O(3) bond length is 1.84 Å. The Cr(2)-O(4) bond length is 1.79 Å. The Cr(2)-O(5) bond length is 1.66 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to one Mg(1) and one Cr(1) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Mg(1) and one Cr(2) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Mg(1), one Cr(1), and one Cr(2) atom. In the fourth O site, O(4) is bonded in a distorted bent 150 degrees geometry to one Cr(1) and one Cr(2) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Mg(1) and one Cr(2) atom. In the sixth O site, O(6) is bonded in a single-bond geometry to one Cr(1) atom.