MgSm4V4O12 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(10), one O(11), one O(3), one O(5), and one O(8) atom to form distorted MgO5 trigonal bipyramids that share  a cornercorner with one V(4)O6 octahedra,  an edgeedge with one V(1)O6 octahedra,  an edgeedge with one V(2)O6 octahedra, and  an edgeedge with one V(4)O6 octahedra. The corner-sharing octahedral tilt angles are 16°. 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 8-coordinate geometry to one O(1), one O(12), one O(3), 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(2), one O(7), one O(8), and one O(9) atom. In the fourth Sm site, Sm(4) is bonded in a 6-coordinate geometry to one O(1), one O(10), one O(11), one O(2), one O(4), and one O(8) atom. There are four inequivalent V sites. In the first V site, V(1) is bonded to one O(1), one O(10), one O(2), one O(3), one O(4), and one O(9) atom to form VO6 octahedra that share corners with four equivalent V(2)O6 octahedra and  an edgeedge with one Mg(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 23-50°. 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, corners with four equivalent V(1)O6 octahedra, and  an edgeedge with one Mg(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 23-50°. In the third V site, V(3) is bonded in a 6-coordinate geometry to one O(10), one O(5), one O(6), one O(7), one O(8), and one O(9) atom. 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 distorted VO6 octahedra that share corners with two equivalent V(2)O6 octahedra,  a cornercorner with one Mg(1)O5 trigonal bipyramid, and  an edgeedge with one Mg(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 40-42°. There are twelve inequivalent O sites. In the first O site, O(1) is bonded to one Sm(2), one Sm(3), one Sm(4), one V(1), and one V(2) atom to form distorted OSm3V2 square pyramids that share corners with three equivalent O(12)Sm2V2 tetrahedra, corners with two equivalent O(2)Sm3V2 trigonal bipyramids,  a cornercorner with one O(9)Sm2V2 trigonal pyramid,  an edgeedge with one O(7)Sm2V2 tetrahedra,  an edgeedge with one O(10)Sm2MgV2 trigonal bipyramid,  an edgeedge with one O(2)Sm3V2 trigonal bipyramid, and  an edgeedge with one O(9)Sm2V2 trigonal pyramid. In the second O site, O(2) is bonded to one Sm(1), one Sm(3), one Sm(4), one V(1), and one V(2) atom to form distorted OSm3V2 trigonal bipyramids that share corners with two equivalent O(1)Sm3V2 square pyramids,  a cornercorner with one O(7)Sm2V2 tetrahedra,  a cornercorner with one O(10)Sm2MgV2 trigonal bipyramid,  an edgeedge with one O(1)Sm3V2 square pyramid,  an edgeedge with one O(12)Sm2V2 tetrahedra,  an edgeedge with one O(10)Sm2MgV2 trigonal bipyramid, and  an edgeedge with one O(9)Sm2V2 trigonal pyramid. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Mg(1), one Sm(1), one Sm(2), one V(1), and one V(2) atom. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to one Sm(1), one Sm(2), one Sm(4), one V(1), and one V(2) atom. In the fifth O site, O(5) is bonded in a 5-coordinate geometry to one Mg(1), one Sm(1), one Sm(2), one V(3), and one V(4) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Sm(1), one Sm(2), one V(3), and one V(4) atom. In the seventh O site, O(7) is bonded to one Sm(2), one Sm(3), one V(3), and one V(4) atom to form OSm2V2 tetrahedra that share corners with three equivalent O(12)Sm2V2 tetrahedra,  a cornercorner with one O(10)Sm2MgV2 trigonal bipyramid,  a cornercorner with one O(2)Sm3V2 trigonal bipyramid,  a cornercorner with one O(9)Sm2V2 trigonal pyramid,  an edgeedge with one O(1)Sm3V2 square pyramid, and  an edgeedge with one O(9)Sm2V2 trigonal pyramid. In the eighth O site, O(8) is bonded in a 6-coordinate geometry to one Mg(1), 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 to one Sm(2), one Sm(3), one V(1), and one V(3) atom to form distorted OSm2V2 trigonal pyramids that share  a cornercorner with one O(1)Sm3V2 square pyramid,  a cornercorner with one O(7)Sm2V2 tetrahedra, corners with two equivalent O(12)Sm2V2 tetrahedra, corners with two equivalent O(10)Sm2MgV2 trigonal bipyramids,  an edgeedge with one O(1)Sm3V2 square pyramid,  an edgeedge with one O(7)Sm2V2 tetrahedra, and  an edgeedge with one O(2)Sm3V2 trigonal bipyramid. In the tenth O site, O(10) is bonded to one Mg(1), one Sm(1), one Sm(4), one V(1), and one V(3) atom to form OSm2MgV2 trigonal bipyramids that share  a cornercorner with one O(7)Sm2V2 tetrahedra,  a cornercorner with one O(2)Sm3V2 trigonal bipyramid, corners with two equivalent O(9)Sm2V2 trigonal pyramids,  an edgeedge with one O(1)Sm3V2 square pyramid, and  an edgeedge with one O(2)Sm3V2 trigonal bipyramid. In the eleventh O site, O(11) is bonded in a 5-coordinate geometry to one Mg(1), one Sm(1), one Sm(4), one V(2), and one V(4) atom. In the twelfth O site, O(12) is bonded to one Sm(2), one Sm(3), one V(2), and one V(4) atom to form distorted OSm2V2 tetrahedra that share corners with three equivalent O(1)Sm3V2 square pyramids, corners with three equivalent O(7)Sm2V2 tetrahedra, corners with two equivalent O(9)Sm2V2 trigonal pyramids, and  an edgeedge with one O(2)Sm3V2 trigonal bipyramid.
MgSm4V4O12 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(10), one O(11), one O(3), one O(5), and one O(8) atom to form distorted MgO5 trigonal bipyramids that share  a cornercorner with one V(4)O6 octahedra,  an edgeedge with one V(1)O6 octahedra,  an edgeedge with one V(2)O6 octahedra, and  an edgeedge with one V(4)O6 octahedra. The corner-sharing octahedral tilt angles are 16°. The Mg(1)-O(10) bond length is 1.99 Å. The Mg(1)-O(11) bond length is 2.11 Å. The Mg(1)-O(3) bond length is 2.03 Å. The Mg(1)-O(5) bond length is 1.91 Å. The Mg(1)-O(8) bond length is 2.14 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 2.27 Å. The Sm(1)-O(11) bond length is 2.89 Å. The Sm(1)-O(2) bond length is 2.51 Å. The Sm(1)-O(3) bond length is 2.49 Å. The Sm(1)-O(4) bond length is 2.55 Å. The Sm(1)-O(5) bond length is 2.33 Å. The Sm(1)-O(6) bond length is 2.68 Å. The Sm(1)-O(8) bond length is 2.63 Å. In the second Sm site, Sm(2) is bonded in a 8-coordinate geometry to one O(1), one O(12), one O(3), 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 2.56 Å. The Sm(2)-O(12) bond length is 2.52 Å. The Sm(2)-O(3) bond length is 2.73 Å. The Sm(2)-O(4) bond length is 2.68 Å. The Sm(2)-O(5) bond length is 2.60 Å. The Sm(2)-O(6) bond length is 2.45 Å. The Sm(2)-O(7) bond length is 2.37 Å. The Sm(2)-O(9) bond length is 2.39 Å. In the third Sm site, Sm(3) is bonded in a 6-coordinate geometry to one O(1), one O(12), one O(2), one O(7), one O(8), and one O(9) atom. The Sm(3)-O(1) bond length is 2.40 Å. The Sm(3)-O(12) bond length is 2.36 Å. The Sm(3)-O(2) bond length is 2.72 Å. The Sm(3)-O(7) bond length is 2.26 Å. The Sm(3)-O(8) bond length is 2.63 Å. The Sm(3)-O(9) bond length is 2.24 Å. In the fourth Sm site, Sm(4) is bonded in a 6-coordinate geometry to one O(1), one O(10), one O(11), one O(2), one O(4), and one O(8) atom. The Sm(4)-O(1) bond length is 2.31 Å. The Sm(4)-O(10) bond length is 2.17 Å. The Sm(4)-O(11) bond length is 2.51 Å. The Sm(4)-O(2) bond length is 2.27 Å. The Sm(4)-O(4) bond length is 2.68 Å. The Sm(4)-O(8) bond length is 2.41 Å. There are four inequivalent V sites. In the first V site, V(1) is bonded to one O(1), one O(10), one O(2), one O(3), one O(4), and one O(9) atom to form VO6 octahedra that share corners with four equivalent V(2)O6 octahedra and  an edgeedge with one Mg(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 23-50°. The V(1)-O(1) bond length is 2.35 Å. The V(1)-O(10) bond length is 2.12 Å. The V(1)-O(2) bond length is 2.22 Å. The V(1)-O(3) bond length is 2.13 Å. The V(1)-O(4) bond length is 2.15 Å. The V(1)-O(9) bond length is 2.00 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, corners with four equivalent V(1)O6 octahedra, and  an edgeedge with one Mg(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 23-50°. The V(2)-O(1) bond length is 2.24 Å. The V(2)-O(11) bond length is 2.17 Å. The V(2)-O(12) bond length is 2.04 Å. The V(2)-O(2) bond length is 2.22 Å. The V(2)-O(3) bond length is 2.02 Å. The V(2)-O(4) bond length is 2.00 Å. In the third V site, V(3) is bonded in a 6-coordinate geometry to one O(10), one O(5), one O(6), one O(7), one O(8), and one O(9) atom. The V(3)-O(10) bond length is 2.10 Å. The V(3)-O(5) bond length is 2.26 Å. The V(3)-O(6) bond length is 2.08 Å. The V(3)-O(7) bond length is 2.14 Å. The V(3)-O(8) bond length is 2.57 Å. The V(3)-O(9) bond length is 2.01 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 distorted VO6 octahedra that share corners with two equivalent V(2)O6 octahedra,  a cornercorner with one Mg(1)O5 trigonal bipyramid, and  an edgeedge with one Mg(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 40-42°. The V(4)-O(11) bond length is 2.11 Å. The V(4)-O(12) bond length is 2.05 Å. The V(4)-O(5) bond length is 2.13 Å. The V(4)-O(6) bond length is 1.96 Å. The V(4)-O(7) bond length is 2.11 Å. The V(4)-O(8) bond length is 2.60 Å. There are twelve inequivalent O sites. In the first O site, O(1) is bonded to one Sm(2), one Sm(3), one Sm(4), one V(1), and one V(2) atom to form distorted OSm3V2 square pyramids that share corners with three equivalent O(12)Sm2V2 tetrahedra, corners with two equivalent O(2)Sm3V2 trigonal bipyramids,  a cornercorner with one O(9)Sm2V2 trigonal pyramid,  an edgeedge with one O(7)Sm2V2 tetrahedra,  an edgeedge with one O(10)Sm2MgV2 trigonal bipyramid,  an edgeedge with one O(2)Sm3V2 trigonal bipyramid, and  an edgeedge with one O(9)Sm2V2 trigonal pyramid. In the second O site, O(2) is bonded to one Sm(1), one Sm(3), one Sm(4), one V(1), and one V(2) atom to form distorted OSm3V2 trigonal bipyramids that share corners with two equivalent O(1)Sm3V2 square pyramids,  a cornercorner with one O(7)Sm2V2 tetrahedra,  a cornercorner with one O(10)Sm2MgV2 trigonal bipyramid,  an edgeedge with one O(1)Sm3V2 square pyramid,  an edgeedge with one O(12)Sm2V2 tetrahedra,  an edgeedge with one O(10)Sm2MgV2 trigonal bipyramid, and  an edgeedge with one O(9)Sm2V2 trigonal pyramid. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Mg(1), one Sm(1), one Sm(2), one V(1), and one V(2) atom. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to one Sm(1), one Sm(2), one Sm(4), one V(1), and one V(2) atom. In the fifth O site, O(5) is bonded in a 5-coordinate geometry to one Mg(1), one Sm(1), one Sm(2), one V(3), and one V(4) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Sm(1), one Sm(2), one V(3), and one V(4) atom. In the seventh O site, O(7) is bonded to one Sm(2), one Sm(3), one V(3), and one V(4) atom to form OSm2V2 tetrahedra that share corners with three equivalent O(12)Sm2V2 tetrahedra,  a cornercorner with one O(10)Sm2MgV2 trigonal bipyramid,  a cornercorner with one O(2)Sm3V2 trigonal bipyramid,  a cornercorner with one O(9)Sm2V2 trigonal pyramid,  an edgeedge with one O(1)Sm3V2 square pyramid, and  an edgeedge with one O(9)Sm2V2 trigonal pyramid. In the eighth O site, O(8) is bonded in a 6-coordinate geometry to one Mg(1), 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 to one Sm(2), one Sm(3), one V(1), and one V(3) atom to form distorted OSm2V2 trigonal pyramids that share  a cornercorner with one O(1)Sm3V2 square pyramid,  a cornercorner with one O(7)Sm2V2 tetrahedra, corners with two equivalent O(12)Sm2V2 tetrahedra, corners with two equivalent O(10)Sm2MgV2 trigonal bipyramids,  an edgeedge with one O(1)Sm3V2 square pyramid,  an edgeedge with one O(7)Sm2V2 tetrahedra, and  an edgeedge with one O(2)Sm3V2 trigonal bipyramid. In the tenth O site, O(10) is bonded to one Mg(1), one Sm(1), one Sm(4), one V(1), and one V(3) atom to form OSm2MgV2 trigonal bipyramids that share  a cornercorner with one O(7)Sm2V2 tetrahedra,  a cornercorner with one O(2)Sm3V2 trigonal bipyramid, corners with two equivalent O(9)Sm2V2 trigonal pyramids,  an edgeedge with one O(1)Sm3V2 square pyramid, and  an edgeedge with one O(2)Sm3V2 trigonal bipyramid. In the eleventh O site, O(11) is bonded in a 5-coordinate geometry to one Mg(1), one Sm(1), one Sm(4), one V(2), and one V(4) atom. In the twelfth O site, O(12) is bonded to one Sm(2), one Sm(3), one V(2), and one V(4) atom to form distorted OSm2V2 tetrahedra that share corners with three equivalent O(1)Sm3V2 square pyramids, corners with three equivalent O(7)Sm2V2 tetrahedra, corners with two equivalent O(9)Sm2V2 trigonal pyramids, and  an edgeedge with one O(2)Sm3V2 trigonal bipyramid.