MgSm4V4O12 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(12), one O(2), one O(4), and one O(9) atom to form distorted MgO4 tetrahedra that share  a cornercorner with one V(2)O6 octahedra,  a cornercorner with one V(3)O6 octahedra,  a cornercorner with one V(4)O6 octahedra, and  an edgeedge with one V(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 19-75°. There are four inequivalent Sm sites. In the first Sm site, Sm(1) is bonded in a 8-coordinate geometry to one O(10), one O(11), one O(2), one O(3), one O(4), one O(5), one O(6), and one O(8) atom. In the second Sm site, Sm(2) is bonded in a 7-coordinate geometry to one O(1), one O(12), one O(4), one O(5), one O(6), one O(7), and one O(9) atom. In the third Sm site, Sm(3) is bonded in a 6-coordinate geometry to one O(1), one O(12), one O(4), one O(6), one O(7), one O(8), and one O(9) atom. In the fourth Sm site, Sm(4) is bonded in a 8-coordinate geometry to one O(1), one O(10), one O(11), one O(2), one O(3), one O(5), one O(7), and one O(8) atom. There are four inequivalent V sites. In the first V site, V(1) is bonded in a 5-coordinate geometry to one O(1), one O(10), one O(2), one O(3), and one O(9) atom. In the second V site, V(2) is bonded to one O(1), one O(11), one O(12), one O(2), one O(3), and one O(4) atom to form VO6 octahedra that share corners with two equivalent V(4)O6 octahedra,  a cornercorner with one Mg(1)O4 tetrahedra, and  an edgeedge with one Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 39-43°. In the third V site, V(3) is bonded to one O(10), one O(5), one O(6), one O(7), one O(8), and one O(9) atom to form VO6 octahedra that share corners with four equivalent V(4)O6 octahedra and  a cornercorner with one Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 32-38°. In the fourth V site, V(4) is bonded to one O(11), one O(12), one O(5), one O(6), one O(7), and one O(8) atom to form VO6 octahedra that share corners with two equivalent V(2)O6 octahedra, corners with four equivalent V(3)O6 octahedra, and  a cornercorner with one Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 32-43°. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Sm(2), one Sm(3), one Sm(4), one V(1), and one V(2) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Mg(1), one Sm(1), one Sm(4), one V(1), and one V(2) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Sm(1), one Sm(4), one V(1), and one V(2) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Mg(1), one Sm(1), one Sm(2), one Sm(3), and one V(2) atom. In the fifth O site, O(5) is bonded to one Sm(1), one Sm(2), one Sm(4), one V(3), and one V(4) atom to form distorted OSm3V2 trigonal bipyramids that share corners with three equivalent O(10)Sm2V2 tetrahedra, corners with two equivalent O(6)Sm3V2 trigonal bipyramids,  a cornercorner with one O(11)Sm2V2 trigonal pyramid,  an edgeedge with one O(6)Sm3V2 trigonal bipyramid, and  an edgeedge with one O(11)Sm2V2 trigonal pyramid. In the sixth O site, O(6) is bonded to one Sm(1), one Sm(2), one Sm(3), one V(3), and one V(4) atom to form distorted OSm3V2 trigonal bipyramids that share corners with two equivalent O(5)Sm3V2 trigonal bipyramids,  an edgeedge with one O(10)Sm2V2 tetrahedra,  an edgeedge with one O(5)Sm3V2 trigonal bipyramid, and  an edgeedge with one O(11)Sm2V2 trigonal pyramid. In the seventh O site, O(7) is bonded in a 5-coordinate geometry to one Sm(2), one Sm(3), one Sm(4), one V(3), and one V(4) atom. In the eighth O site, O(8) is bonded in a 5-coordinate geometry to one Sm(1), one Sm(3), one Sm(4), one V(3), and one V(4) atom. In the ninth O site, O(9) is bonded in a 5-coordinate geometry to one Mg(1), one Sm(2), one Sm(3), one V(1), and one V(3) atom. In the tenth O site, O(10) is bonded to one Sm(1), one Sm(4), one V(1), and one V(3) atom to form distorted OSm2V2 tetrahedra that share corners with three equivalent O(5)Sm3V2 trigonal bipyramids, corners with two equivalent O(11)Sm2V2 trigonal pyramids, and  an edgeedge with one O(6)Sm3V2 trigonal bipyramid. In the eleventh O site, O(11) is bonded to one Sm(1), one Sm(4), one V(2), and one V(4) atom to form distorted OSm2V2 trigonal pyramids that share corners with two equivalent O(10)Sm2V2 tetrahedra,  a cornercorner with one O(5)Sm3V2 trigonal bipyramid,  an edgeedge with one O(5)Sm3V2 trigonal bipyramid, and  an edgeedge with one O(6)Sm3V2 trigonal bipyramid. In the twelfth O site, O(12) is bonded in a 5-coordinate geometry to one Mg(1), one Sm(2), one Sm(3), one V(2), and one V(4) atom.
MgSm4V4O12 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(12), one O(2), one O(4), and one O(9) atom to form distorted MgO4 tetrahedra that share  a cornercorner with one V(2)O6 octahedra,  a cornercorner with one V(3)O6 octahedra,  a cornercorner with one V(4)O6 octahedra, and  an edgeedge with one V(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 19-75°. The Mg(1)-O(12) bond length is 1.92 Å. The Mg(1)-O(2) bond length is 1.95 Å. The Mg(1)-O(4) bond length is 1.88 Å. The Mg(1)-O(9) bond length is 1.93 Å. There are four inequivalent Sm sites. In the first Sm site, Sm(1) is bonded in a 8-coordinate geometry to one O(10), one O(11), one O(2), one O(3), one O(4), one O(5), one O(6), and one O(8) atom. The Sm(1)-O(10) bond length is 2.40 Å. The Sm(1)-O(11) bond length is 2.33 Å. The Sm(1)-O(2) bond length is 2.62 Å. The Sm(1)-O(3) bond length is 2.40 Å. The Sm(1)-O(4) bond length is 3.05 Å. The Sm(1)-O(5) bond length is 2.36 Å. The Sm(1)-O(6) bond length is 2.57 Å. The Sm(1)-O(8) bond length is 2.65 Å. In the second Sm site, Sm(2) is bonded in a 7-coordinate geometry to one O(1), one O(12), one O(4), one O(5), one O(6), one O(7), and one O(9) atom. The Sm(2)-O(1) bond length is 2.52 Å. The Sm(2)-O(12) bond length is 2.59 Å. The Sm(2)-O(4) bond length is 2.50 Å. The Sm(2)-O(5) bond length is 2.46 Å. The Sm(2)-O(6) bond length is 2.35 Å. The Sm(2)-O(7) bond length is 2.33 Å. The Sm(2)-O(9) bond length is 2.32 Å. In the third Sm site, Sm(3) is bonded in a 6-coordinate geometry to one O(1), one O(12), one O(4), one O(6), one O(7), one O(8), and one O(9) atom. The Sm(3)-O(1) bond length is 2.38 Å. The Sm(3)-O(12) bond length is 2.59 Å. The Sm(3)-O(4) bond length is 2.43 Å. The Sm(3)-O(6) bond length is 2.44 Å. The Sm(3)-O(7) bond length is 2.29 Å. The Sm(3)-O(8) bond length is 2.94 Å. The Sm(3)-O(9) bond length is 2.42 Å. In the fourth Sm site, Sm(4) is bonded in a 8-coordinate geometry to one O(1), one O(10), one O(11), one O(2), one O(3), one O(5), one O(7), and one O(8) atom. The Sm(4)-O(1) bond length is 3.02 Å. The Sm(4)-O(10) bond length is 2.26 Å. The Sm(4)-O(11) bond length is 2.45 Å. The Sm(4)-O(2) bond length is 2.55 Å. The Sm(4)-O(3) bond length is 2.53 Å. The Sm(4)-O(5) bond length is 2.52 Å. The Sm(4)-O(7) bond length is 2.70 Å. The Sm(4)-O(8) bond length is 2.34 Å. There are four inequivalent V sites. In the first V site, V(1) is bonded in a 5-coordinate geometry to one O(1), one O(10), one O(2), one O(3), and one O(9) atom. The V(1)-O(1) bond length is 1.95 Å. The V(1)-O(10) bond length is 1.96 Å. The V(1)-O(2) bond length is 2.09 Å. The V(1)-O(3) bond length is 1.89 Å. The V(1)-O(9) bond length is 2.34 Å. In the second V site, V(2) is bonded to one O(1), one O(11), one O(12), one O(2), one O(3), and one O(4) atom to form VO6 octahedra that share corners with two equivalent V(4)O6 octahedra,  a cornercorner with one Mg(1)O4 tetrahedra, and  an edgeedge with one Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 39-43°. The V(2)-O(1) bond length is 2.17 Å. The V(2)-O(11) bond length is 2.15 Å. The V(2)-O(12) bond length is 2.27 Å. The V(2)-O(2) bond length is 2.40 Å. The V(2)-O(3) bond length is 2.15 Å. The V(2)-O(4) bond length is 2.12 Å. In the third V site, V(3) is bonded to one O(10), one O(5), one O(6), one O(7), one O(8), and one O(9) atom to form VO6 octahedra that share corners with four equivalent V(4)O6 octahedra and  a cornercorner with one Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 32-38°. The V(3)-O(10) bond length is 2.11 Å. The V(3)-O(5) bond length is 2.24 Å. The V(3)-O(6) bond length is 2.23 Å. The V(3)-O(7) bond length is 2.19 Å. The V(3)-O(8) bond length is 2.09 Å. The V(3)-O(9) bond length is 2.28 Å. In the fourth V site, V(4) is bonded to one O(11), one O(12), one O(5), one O(6), one O(7), and one O(8) atom to form VO6 octahedra that share corners with two equivalent V(2)O6 octahedra, corners with four equivalent V(3)O6 octahedra, and  a cornercorner with one Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 32-43°. The V(4)-O(11) bond length is 2.02 Å. The V(4)-O(12) bond length is 2.11 Å. The V(4)-O(5) bond length is 2.14 Å. The V(4)-O(6) bond length is 2.18 Å. The V(4)-O(7) bond length is 2.13 Å. The V(4)-O(8) bond length is 1.99 Å. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Sm(2), one Sm(3), one Sm(4), one V(1), and one V(2) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Mg(1), one Sm(1), one Sm(4), one V(1), and one V(2) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Sm(1), one Sm(4), one V(1), and one V(2) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Mg(1), one Sm(1), one Sm(2), one Sm(3), and one V(2) atom. In the fifth O site, O(5) is bonded to one Sm(1), one Sm(2), one Sm(4), one V(3), and one V(4) atom to form distorted OSm3V2 trigonal bipyramids that share corners with three equivalent O(10)Sm2V2 tetrahedra, corners with two equivalent O(6)Sm3V2 trigonal bipyramids,  a cornercorner with one O(11)Sm2V2 trigonal pyramid,  an edgeedge with one O(6)Sm3V2 trigonal bipyramid, and  an edgeedge with one O(11)Sm2V2 trigonal pyramid. In the sixth O site, O(6) is bonded to one Sm(1), one Sm(2), one Sm(3), one V(3), and one V(4) atom to form distorted OSm3V2 trigonal bipyramids that share corners with two equivalent O(5)Sm3V2 trigonal bipyramids,  an edgeedge with one O(10)Sm2V2 tetrahedra,  an edgeedge with one O(5)Sm3V2 trigonal bipyramid, and  an edgeedge with one O(11)Sm2V2 trigonal pyramid. In the seventh O site, O(7) is bonded in a 5-coordinate geometry to one Sm(2), one Sm(3), one Sm(4), one V(3), and one V(4) atom. In the eighth O site, O(8) is bonded in a 5-coordinate geometry to one Sm(1), one Sm(3), one Sm(4), one V(3), and one V(4) atom. In the ninth O site, O(9) is bonded in a 5-coordinate geometry to one Mg(1), one Sm(2), one Sm(3), one V(1), and one V(3) atom. In the tenth O site, O(10) is bonded to one Sm(1), one Sm(4), one V(1), and one V(3) atom to form distorted OSm2V2 tetrahedra that share corners with three equivalent O(5)Sm3V2 trigonal bipyramids, corners with two equivalent O(11)Sm2V2 trigonal pyramids, and  an edgeedge with one O(6)Sm3V2 trigonal bipyramid. In the eleventh O site, O(11) is bonded to one Sm(1), one Sm(4), one V(2), and one V(4) atom to form distorted OSm2V2 trigonal pyramids that share corners with two equivalent O(10)Sm2V2 tetrahedra,  a cornercorner with one O(5)Sm3V2 trigonal bipyramid,  an edgeedge with one O(5)Sm3V2 trigonal bipyramid, and  an edgeedge with one O(6)Sm3V2 trigonal bipyramid. In the twelfth O site, O(12) is bonded in a 5-coordinate geometry to one Mg(1), one Sm(2), one Sm(3), one V(2), and one V(4) atom.