MgMo2Fe2(O4Cl)2 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(2), one O(3), one O(5), one O(8), and one Cl(1) atom to form distorted MgClO4 trigonal bipyramids that share  an edgeedge with one Mo(1)O4 tetrahedra and  an edgeedge with one Mo(2)O4 tetrahedra. There are two inequivalent Mo sites. In the first Mo site, Mo(1) is bonded to one O(3), one O(4), one O(6), and one O(8) atom to form MoO4 tetrahedra that share  an edgeedge with one Mg(1)ClO4 trigonal bipyramid. In the second Mo site, Mo(2) is bonded to one O(1), one O(2), one O(5), and one O(7) atom to form MoO4 tetrahedra that share  an edgeedge with one Mg(1)ClO4 trigonal bipyramid. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(3), one O(4), and two equivalent Cl(1) atoms. In the second Fe site, Fe(2) is bonded in a 5-coordinate geometry to one O(5), one O(6), one O(7), one O(8), and one Cl(2) atom. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Mo(2) and one Fe(1) atom. In the second O site, O(2) is bonded in a T-shaped geometry to one Mg(1), one Mo(2), and one Fe(1) atom. In the third O site, O(3) is bonded in a T-shaped geometry to one Mg(1), one Mo(1), and one Fe(1) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Mo(1) and one Fe(1) atom. In the fifth O site, O(5) is bonded in a T-shaped geometry to one Mg(1), one Mo(2), and one Fe(2) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one Mo(1) and one Fe(2) atom. In the seventh O site, O(7) is bonded in a bent 150 degrees geometry to one Mo(2) and one Fe(2) atom. In the eighth O site, O(8) is bonded in a T-shaped geometry to one Mg(1), one Mo(1), and one Fe(2) atom. There are two inequivalent Cl sites. In the first Cl site, Cl(1) is bonded in a distorted bent 120 degrees geometry to one Mg(1) and two equivalent Fe(1) atoms. In the second Cl site, Cl(2) is bonded in a distorted single-bond geometry to one Fe(2) atom.
MgMo2Fe2(O4Cl)2 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(2), one O(3), one O(5), one O(8), and one Cl(1) atom to form distorted MgClO4 trigonal bipyramids that share  an edgeedge with one Mo(1)O4 tetrahedra and  an edgeedge with one Mo(2)O4 tetrahedra. The Mg(1)-O(2) bond length is 2.12 Å. The Mg(1)-O(3) bond length is 2.12 Å. The Mg(1)-O(5) bond length is 2.04 Å. The Mg(1)-O(8) bond length is 2.04 Å. The Mg(1)-Cl(1) bond length is 2.39 Å. There are two inequivalent Mo sites. In the first Mo site, Mo(1) is bonded to one O(3), one O(4), one O(6), and one O(8) atom to form MoO4 tetrahedra that share  an edgeedge with one Mg(1)ClO4 trigonal bipyramid. The Mo(1)-O(3) bond length is 1.83 Å. The Mo(1)-O(4) bond length is 1.78 Å. The Mo(1)-O(6) bond length is 1.77 Å. The Mo(1)-O(8) bond length is 1.84 Å. In the second Mo site, Mo(2) is bonded to one O(1), one O(2), one O(5), and one O(7) atom to form MoO4 tetrahedra that share  an edgeedge with one Mg(1)ClO4 trigonal bipyramid. The Mo(2)-O(1) bond length is 1.78 Å. The Mo(2)-O(2) bond length is 1.83 Å. The Mo(2)-O(5) bond length is 1.84 Å. The Mo(2)-O(7) bond length is 1.77 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(3), one O(4), and two equivalent Cl(1) atoms. The Fe(1)-O(1) bond length is 2.04 Å. The Fe(1)-O(2) bond length is 2.19 Å. The Fe(1)-O(3) bond length is 2.20 Å. The Fe(1)-O(4) bond length is 2.05 Å. There is one shorter (2.43 Å) and one longer (2.92 Å) Fe(1)-Cl(1) bond length. In the second Fe site, Fe(2) is bonded in a 5-coordinate geometry to one O(5), one O(6), one O(7), one O(8), and one Cl(2) atom. The Fe(2)-O(5) bond length is 2.27 Å. The Fe(2)-O(6) bond length is 2.06 Å. The Fe(2)-O(7) bond length is 2.07 Å. The Fe(2)-O(8) bond length is 2.25 Å. The Fe(2)-Cl(2) bond length is 2.37 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Mo(2) and one Fe(1) atom. In the second O site, O(2) is bonded in a T-shaped geometry to one Mg(1), one Mo(2), and one Fe(1) atom. In the third O site, O(3) is bonded in a T-shaped geometry to one Mg(1), one Mo(1), and one Fe(1) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Mo(1) and one Fe(1) atom. In the fifth O site, O(5) is bonded in a T-shaped geometry to one Mg(1), one Mo(2), and one Fe(2) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one Mo(1) and one Fe(2) atom. In the seventh O site, O(7) is bonded in a bent 150 degrees geometry to one Mo(2) and one Fe(2) atom. In the eighth O site, O(8) is bonded in a T-shaped geometry to one Mg(1), one Mo(1), and one Fe(2) atom. There are two inequivalent Cl sites. In the first Cl site, Cl(1) is bonded in a distorted bent 120 degrees geometry to one Mg(1) and two equivalent Fe(1) atoms. In the second Cl site, Cl(2) is bonded in a distorted single-bond geometry to one Fe(2) atom.