MgCr3(SO4)6 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(12), one O(14), one O(3), one O(6), and one O(8) atom to form MgO5 trigonal bipyramids that share  a cornercorner with one Cr(1)O6 octahedra,  a cornercorner with one Cr(3)O6 octahedra,  a cornercorner with one S(2)O4 tetrahedra,  a cornercorner with one S(3)O4 tetrahedra,  a cornercorner with one S(5)O4 tetrahedra, and  an edgeedge with one S(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 57-63°. There are three inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(1), one O(2), one O(4), one O(6), one O(7), and one O(9) atom to form CrO6 octahedra that share  a cornercorner with one S(1)O4 tetrahedra,  a cornercorner with one S(2)O4 tetrahedra,  a cornercorner with one S(3)O4 tetrahedra,  a cornercorner with one S(4)O4 tetrahedra,  a cornercorner with one S(5)O4 tetrahedra,  a cornercorner with one S(6)O4 tetrahedra, and  a cornercorner with one Mg(1)O5 trigonal bipyramid. In the second Cr site, Cr(2) is bonded to one O(16), one O(18), one O(19), one O(21), one O(23), and one O(24) atom to form CrO6 octahedra that share  a cornercorner with one S(1)O4 tetrahedra,  a cornercorner with one S(2)O4 tetrahedra,  a cornercorner with one S(3)O4 tetrahedra,  a cornercorner with one S(4)O4 tetrahedra,  a cornercorner with one S(5)O4 tetrahedra, and  a cornercorner with one S(6)O4 tetrahedra. In the third Cr site, Cr(3) is bonded to one O(10), one O(13), one O(14), one O(17), one O(22), and one O(5) atom to form CrO6 octahedra that share  a cornercorner with one S(1)O4 tetrahedra,  a cornercorner with one S(2)O4 tetrahedra,  a cornercorner with one S(3)O4 tetrahedra,  a cornercorner with one S(4)O4 tetrahedra,  a cornercorner with one S(5)O4 tetrahedra,  a cornercorner with one S(6)O4 tetrahedra, and  a cornercorner with one Mg(1)O5 trigonal bipyramid. There are six inequivalent S sites. In the first S site, S(1) is bonded to one O(24), one O(3), one O(5), and one O(6) atom to form SO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra,  a cornercorner with one Cr(2)O6 octahedra,  a cornercorner with one Cr(3)O6 octahedra, and  an edgeedge with one Mg(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 33-49°. In the second S site, S(2) is bonded to one O(13), one O(21), one O(7), and one O(8) atom to form SO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra,  a cornercorner with one Cr(2)O6 octahedra,  a cornercorner with one Cr(3)O6 octahedra, and  a cornercorner with one Mg(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 28-44°. In the third S site, S(3) is bonded to one O(14), one O(15), one O(23), and one O(9) atom to form SO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra,  a cornercorner with one Cr(2)O6 octahedra,  a cornercorner with one Cr(3)O6 octahedra, and  a cornercorner with one Mg(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 28-56°. In the fourth S site, S(4) is bonded to one O(10), one O(11), one O(16), and one O(2) atom to form SO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra,  a cornercorner with one Cr(2)O6 octahedra, and  a cornercorner with one Cr(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 32-41°. In the fifth S site, S(5) is bonded to one O(12), one O(17), one O(18), and one O(4) atom to form SO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra,  a cornercorner with one Cr(2)O6 octahedra,  a cornercorner with one Cr(3)O6 octahedra, and  a cornercorner with one Mg(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 22-41°. In the sixth S site, S(6) is bonded to one O(1), one O(19), one O(20), and one O(22) atom to form SO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra,  a cornercorner with one Cr(2)O6 octahedra, and  a cornercorner with one Cr(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 33-43°. There are twenty-four inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Cr(1) and one S(6) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Cr(1) and one S(4) atom. In the third O site, O(3) is bonded in an L-shaped geometry to one Mg(1) and one S(1) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Cr(1) and one S(5) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Cr(3) and one S(1) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Mg(1), one Cr(1), and one S(1) atom. In the seventh O site, O(7) is bonded in a distorted bent 150 degrees geometry to one Cr(1) and one S(2) atom. In the eighth O site, O(8) is bonded in a distorted bent 150 degrees geometry to one Mg(1) and one S(2) atom. In the ninth O site, O(9) is bonded in a bent 150 degrees geometry to one Cr(1) and one S(3) atom. In the tenth O site, O(10) is bonded in a bent 150 degrees geometry to one Cr(3) and one S(4) atom. In the eleventh O site, O(11) is bonded in a single-bond geometry to one S(4) atom. In the twelfth O site, O(12) is bonded in a bent 120 degrees geometry to one Mg(1) and one S(5) atom. In the thirteenth O site, O(13) is bonded in a bent 150 degrees geometry to one Cr(3) and one S(2) atom. In the fourteenth O site, O(14) is bonded in a trigonal planar geometry to one Mg(1), one Cr(3), and one S(3) atom. In the fifteenth O site, O(15) is bonded in a single-bond geometry to one S(3) atom. In the sixteenth O site, O(16) is bonded in a bent 150 degrees geometry to one Cr(2) and one S(4) atom. In the seventeenth O site, O(17) is bonded in a bent 150 degrees geometry to one Cr(3) and one S(5) atom. In the eighteenth O site, O(18) is bonded in a bent 150 degrees geometry to one Cr(2) and one S(5) atom. In the nineteenth O site, O(19) is bonded in a distorted bent 150 degrees geometry to one Cr(2) and one S(6) atom. In the twentieth O site, O(20) is bonded in a single-bond geometry to one S(6) atom. In the twenty-first O site, O(21) is bonded in a bent 150 degrees geometry to one Cr(2) and one S(2) atom. In the twenty-second O site, O(22) is bonded in a bent 150 degrees geometry to one Cr(3) and one S(6) atom. In the twenty-third O site, O(23) is bonded in a bent 150 degrees geometry to one Cr(2) and one S(3) atom. In the twenty-fourth O site, O(24) is bonded in a bent 150 degrees geometry to one Cr(2) and one S(1) atom.
MgCr3(SO4)6 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(12), one O(14), one O(3), one O(6), and one O(8) atom to form MgO5 trigonal bipyramids that share  a cornercorner with one Cr(1)O6 octahedra,  a cornercorner with one Cr(3)O6 octahedra,  a cornercorner with one S(2)O4 tetrahedra,  a cornercorner with one S(3)O4 tetrahedra,  a cornercorner with one S(5)O4 tetrahedra, and  an edgeedge with one S(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 57-63°. The Mg(1)-O(12) bond length is 1.95 Å. The Mg(1)-O(14) bond length is 2.29 Å. The Mg(1)-O(3) bond length is 2.15 Å. The Mg(1)-O(6) bond length is 2.12 Å. The Mg(1)-O(8) bond length is 1.93 Å. There are three inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(1), one O(2), one O(4), one O(6), one O(7), and one O(9) atom to form CrO6 octahedra that share  a cornercorner with one S(1)O4 tetrahedra,  a cornercorner with one S(2)O4 tetrahedra,  a cornercorner with one S(3)O4 tetrahedra,  a cornercorner with one S(4)O4 tetrahedra,  a cornercorner with one S(5)O4 tetrahedra,  a cornercorner with one S(6)O4 tetrahedra, and  a cornercorner with one Mg(1)O5 trigonal bipyramid. The Cr(1)-O(1) bond length is 2.00 Å. The Cr(1)-O(2) bond length is 2.04 Å. The Cr(1)-O(4) bond length is 2.00 Å. The Cr(1)-O(6) bond length is 2.07 Å. The Cr(1)-O(7) bond length is 2.02 Å. The Cr(1)-O(9) bond length is 1.99 Å. In the second Cr site, Cr(2) is bonded to one O(16), one O(18), one O(19), one O(21), one O(23), and one O(24) atom to form CrO6 octahedra that share  a cornercorner with one S(1)O4 tetrahedra,  a cornercorner with one S(2)O4 tetrahedra,  a cornercorner with one S(3)O4 tetrahedra,  a cornercorner with one S(4)O4 tetrahedra,  a cornercorner with one S(5)O4 tetrahedra, and  a cornercorner with one S(6)O4 tetrahedra. The Cr(2)-O(16) bond length is 2.01 Å. The Cr(2)-O(18) bond length is 2.02 Å. The Cr(2)-O(19) bond length is 2.00 Å. The Cr(2)-O(21) bond length is 1.96 Å. The Cr(2)-O(23) bond length is 1.97 Å. The Cr(2)-O(24) bond length is 1.99 Å. In the third Cr site, Cr(3) is bonded to one O(10), one O(13), one O(14), one O(17), one O(22), and one O(5) atom to form CrO6 octahedra that share  a cornercorner with one S(1)O4 tetrahedra,  a cornercorner with one S(2)O4 tetrahedra,  a cornercorner with one S(3)O4 tetrahedra,  a cornercorner with one S(4)O4 tetrahedra,  a cornercorner with one S(5)O4 tetrahedra,  a cornercorner with one S(6)O4 tetrahedra, and  a cornercorner with one Mg(1)O5 trigonal bipyramid. The Cr(3)-O(10) bond length is 2.05 Å. The Cr(3)-O(13) bond length is 2.01 Å. The Cr(3)-O(14) bond length is 2.07 Å. The Cr(3)-O(17) bond length is 2.00 Å. The Cr(3)-O(22) bond length is 2.03 Å. The Cr(3)-O(5) bond length is 2.02 Å. There are six inequivalent S sites. In the first S site, S(1) is bonded to one O(24), one O(3), one O(5), and one O(6) atom to form SO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra,  a cornercorner with one Cr(2)O6 octahedra,  a cornercorner with one Cr(3)O6 octahedra, and  an edgeedge with one Mg(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 33-49°. The S(1)-O(24) bond length is 1.47 Å. The S(1)-O(3) bond length is 1.46 Å. The S(1)-O(5) bond length is 1.48 Å. The S(1)-O(6) bond length is 1.54 Å. In the second S site, S(2) is bonded to one O(13), one O(21), one O(7), and one O(8) atom to form SO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra,  a cornercorner with one Cr(2)O6 octahedra,  a cornercorner with one Cr(3)O6 octahedra, and  a cornercorner with one Mg(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 28-44°. The S(2)-O(13) bond length is 1.50 Å. The S(2)-O(21) bond length is 1.48 Å. The S(2)-O(7) bond length is 1.47 Å. The S(2)-O(8) bond length is 1.47 Å. In the third S site, S(3) is bonded to one O(14), one O(15), one O(23), and one O(9) atom to form SO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra,  a cornercorner with one Cr(2)O6 octahedra,  a cornercorner with one Cr(3)O6 octahedra, and  a cornercorner with one Mg(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 28-56°. The S(3)-O(14) bond length is 1.57 Å. The S(3)-O(15) bond length is 1.42 Å. The S(3)-O(23) bond length is 1.49 Å. The S(3)-O(9) bond length is 1.49 Å. In the fourth S site, S(4) is bonded to one O(10), one O(11), one O(16), and one O(2) atom to form SO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra,  a cornercorner with one Cr(2)O6 octahedra, and  a cornercorner with one Cr(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 32-41°. The S(4)-O(10) bond length is 1.49 Å. The S(4)-O(11) bond length is 1.45 Å. The S(4)-O(16) bond length is 1.51 Å. The S(4)-O(2) bond length is 1.50 Å. In the fifth S site, S(5) is bonded to one O(12), one O(17), one O(18), and one O(4) atom to form SO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra,  a cornercorner with one Cr(2)O6 octahedra,  a cornercorner with one Cr(3)O6 octahedra, and  a cornercorner with one Mg(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 22-41°. The S(5)-O(12) bond length is 1.47 Å. The S(5)-O(17) bond length is 1.49 Å. The S(5)-O(18) bond length is 1.49 Å. The S(5)-O(4) bond length is 1.47 Å. In the sixth S site, S(6) is bonded to one O(1), one O(19), one O(20), and one O(22) atom to form SO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra,  a cornercorner with one Cr(2)O6 octahedra, and  a cornercorner with one Cr(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 33-43°. The S(6)-O(1) bond length is 1.49 Å. The S(6)-O(19) bond length is 1.51 Å. The S(6)-O(20) bond length is 1.46 Å. The S(6)-O(22) bond length is 1.49 Å. There are twenty-four inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Cr(1) and one S(6) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Cr(1) and one S(4) atom. In the third O site, O(3) is bonded in an L-shaped geometry to one Mg(1) and one S(1) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Cr(1) and one S(5) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Cr(3) and one S(1) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Mg(1), one Cr(1), and one S(1) atom. In the seventh O site, O(7) is bonded in a distorted bent 150 degrees geometry to one Cr(1) and one S(2) atom. In the eighth O site, O(8) is bonded in a distorted bent 150 degrees geometry to one Mg(1) and one S(2) atom. In the ninth O site, O(9) is bonded in a bent 150 degrees geometry to one Cr(1) and one S(3) atom. In the tenth O site, O(10) is bonded in a bent 150 degrees geometry to one Cr(3) and one S(4) atom. In the eleventh O site, O(11) is bonded in a single-bond geometry to one S(4) atom. In the twelfth O site, O(12) is bonded in a bent 120 degrees geometry to one Mg(1) and one S(5) atom. In the thirteenth O site, O(13) is bonded in a bent 150 degrees geometry to one Cr(3) and one S(2) atom. In the fourteenth O site, O(14) is bonded in a trigonal planar geometry to one Mg(1), one Cr(3), and one S(3) atom. In the fifteenth O site, O(15) is bonded in a single-bond geometry to one S(3) atom. In the sixteenth O site, O(16) is bonded in a bent 150 degrees geometry to one Cr(2) and one S(4) atom. In the seventeenth O site, O(17) is bonded in a bent 150 degrees geometry to one Cr(3) and one S(5) atom. In the eighteenth O site, O(18) is bonded in a bent 150 degrees geometry to one Cr(2) and one S(5) atom. In the nineteenth O site, O(19) is bonded in a distorted bent 150 degrees geometry to one Cr(2) and one S(6) atom. In the twentieth O site, O(20) is bonded in a single-bond geometry to one S(6) atom. In the twenty-first O site, O(21) is bonded in a bent 150 degrees geometry to one Cr(2) and one S(2) atom. In the twenty-second O site, O(22) is bonded in a bent 150 degrees geometry to one Cr(3) and one S(6) atom. In the twenty-third O site, O(23) is bonded in a bent 150 degrees geometry to one Cr(2) and one S(3) atom. In the twenty-fourth O site, O(24) is bonded in a bent 150 degrees geometry to one Cr(2) and one S(1) atom.