Sm3MoO7 crystallizes in the orthorhombic P2_12_12_1 space group. There are three inequivalent Sm sites. In the first Sm site, Sm(1) is bonded in a 7-coordinate geometry to one O(5), one O(6), one O(7), two equivalent O(1), and two equivalent O(2) atoms. In the second Sm site, Sm(2) is bonded to one O(3), one O(4), one O(5), one O(6), one O(7), and two equivalent O(2) atoms to form distorted SmO7 pentagonal bipyramids that share corners with two equivalent Mo(1)O6 octahedra, corners with two equivalent Sm(2)O7 pentagonal bipyramids, and edges with two equivalent Mo(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 39-42°. In the third Sm site, Sm(3) is bonded in a 7-coordinate geometry to one O(3), one O(4), one O(5), one O(6), one O(7), and two equivalent O(1) atoms. Mo(1) is bonded to one O(4), one O(5), one O(6), one O(7), and two equivalent O(3) atoms to form MoO6 octahedra that share corners with two equivalent Mo(1)O6 octahedra, corners with two equivalent Sm(2)O7 pentagonal bipyramids, and edges with two equivalent Sm(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 30°. There are seven inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Sm(1) and two equivalent Sm(3) atoms to form OSm4 tetrahedra that share corners with two equivalent O(7)Sm3Mo tetrahedra, corners with two equivalent O(2)Sm4 tetrahedra, corners with four equivalent O(1)Sm4 tetrahedra, corners with two equivalent O(5)Sm3Mo trigonal pyramids,  an edgeedge with one O(7)Sm3Mo tetrahedra,  an edgeedge with one O(2)Sm4 tetrahedra, and  an edgeedge with one O(5)Sm3Mo trigonal pyramid. In the second O site, O(2) is bonded to two equivalent Sm(1) and two equivalent Sm(2) atoms to form OSm4 tetrahedra that share corners with two equivalent O(7)Sm3Mo tetrahedra, corners with two equivalent O(1)Sm4 tetrahedra, corners with four equivalent O(2)Sm4 tetrahedra, corners with two equivalent O(5)Sm3Mo trigonal pyramids,  an edgeedge with one O(7)Sm3Mo tetrahedra,  an edgeedge with one O(1)Sm4 tetrahedra, and  an edgeedge with one O(5)Sm3Mo trigonal pyramid. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Sm(2), one Sm(3), and two equivalent Mo(1) atoms. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Sm(2), one Sm(3), and one Mo(1) atom. In the fifth O site, O(5) is bonded to one Sm(1), one Sm(2), one Sm(3), and one Mo(1) atom to form distorted OSm3Mo trigonal pyramids that share corners with two equivalent O(1)Sm4 tetrahedra, corners with two equivalent O(2)Sm4 tetrahedra,  an edgeedge with one O(1)Sm4 tetrahedra,  an edgeedge with one O(2)Sm4 tetrahedra, and edges with two equivalent O(7)Sm3Mo tetrahedra. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to one Sm(1), one Sm(2), one Sm(3), and one Mo(1) atom. In the seventh O site, O(7) is bonded to one Sm(1), one Sm(2), one Sm(3), and one Mo(1) atom to form OSm3Mo tetrahedra that share corners with two equivalent O(1)Sm4 tetrahedra, corners with two equivalent O(2)Sm4 tetrahedra,  an edgeedge with one O(1)Sm4 tetrahedra,  an edgeedge with one O(2)Sm4 tetrahedra, and edges with two equivalent O(5)Sm3Mo trigonal pyramids.
Sm3MoO7 crystallizes in the orthorhombic P2_12_12_1 space group. There are three inequivalent Sm sites. In the first Sm site, Sm(1) is bonded in a 7-coordinate geometry to one O(5), one O(6), one O(7), two equivalent O(1), and two equivalent O(2) atoms. The Sm(1)-O(5) bond length is 2.44 Å. The Sm(1)-O(6) bond length is 2.90 Å. The Sm(1)-O(7) bond length is 2.33 Å. There is one shorter (2.36 Å) and one longer (2.38 Å) Sm(1)-O(1) bond length. There is one shorter (2.38 Å) and one longer (2.41 Å) Sm(1)-O(2) bond length. In the second Sm site, Sm(2) is bonded to one O(3), one O(4), one O(5), one O(6), one O(7), and two equivalent O(2) atoms to form distorted SmO7 pentagonal bipyramids that share corners with two equivalent Mo(1)O6 octahedra, corners with two equivalent Sm(2)O7 pentagonal bipyramids, and edges with two equivalent Mo(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 39-42°. The Sm(2)-O(3) bond length is 2.58 Å. The Sm(2)-O(4) bond length is 2.43 Å. The Sm(2)-O(5) bond length is 2.42 Å. The Sm(2)-O(6) bond length is 2.43 Å. The Sm(2)-O(7) bond length is 2.37 Å. There is one shorter (2.27 Å) and one longer (2.28 Å) Sm(2)-O(2) bond length. In the third Sm site, Sm(3) is bonded in a 7-coordinate geometry to one O(3), one O(4), one O(5), one O(6), one O(7), and two equivalent O(1) atoms. The Sm(3)-O(3) bond length is 2.67 Å. The Sm(3)-O(4) bond length is 2.40 Å. The Sm(3)-O(5) bond length is 2.41 Å. The Sm(3)-O(6) bond length is 2.42 Å. The Sm(3)-O(7) bond length is 2.37 Å. There is one shorter (2.29 Å) and one longer (2.32 Å) Sm(3)-O(1) bond length. Mo(1) is bonded to one O(4), one O(5), one O(6), one O(7), and two equivalent O(3) atoms to form MoO6 octahedra that share corners with two equivalent Mo(1)O6 octahedra, corners with two equivalent Sm(2)O7 pentagonal bipyramids, and edges with two equivalent Sm(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 30°. The Mo(1)-O(4) bond length is 1.88 Å. The Mo(1)-O(5) bond length is 2.00 Å. The Mo(1)-O(6) bond length is 1.93 Å. The Mo(1)-O(7) bond length is 2.08 Å. There is one shorter (1.94 Å) and one longer (1.95 Å) Mo(1)-O(3) bond length. There are seven inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Sm(1) and two equivalent Sm(3) atoms to form OSm4 tetrahedra that share corners with two equivalent O(7)Sm3Mo tetrahedra, corners with two equivalent O(2)Sm4 tetrahedra, corners with four equivalent O(1)Sm4 tetrahedra, corners with two equivalent O(5)Sm3Mo trigonal pyramids,  an edgeedge with one O(7)Sm3Mo tetrahedra,  an edgeedge with one O(2)Sm4 tetrahedra, and  an edgeedge with one O(5)Sm3Mo trigonal pyramid. In the second O site, O(2) is bonded to two equivalent Sm(1) and two equivalent Sm(2) atoms to form OSm4 tetrahedra that share corners with two equivalent O(7)Sm3Mo tetrahedra, corners with two equivalent O(1)Sm4 tetrahedra, corners with four equivalent O(2)Sm4 tetrahedra, corners with two equivalent O(5)Sm3Mo trigonal pyramids,  an edgeedge with one O(7)Sm3Mo tetrahedra,  an edgeedge with one O(1)Sm4 tetrahedra, and  an edgeedge with one O(5)Sm3Mo trigonal pyramid. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Sm(2), one Sm(3), and two equivalent Mo(1) atoms. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Sm(2), one Sm(3), and one Mo(1) atom. In the fifth O site, O(5) is bonded to one Sm(1), one Sm(2), one Sm(3), and one Mo(1) atom to form distorted OSm3Mo trigonal pyramids that share corners with two equivalent O(1)Sm4 tetrahedra, corners with two equivalent O(2)Sm4 tetrahedra,  an edgeedge with one O(1)Sm4 tetrahedra,  an edgeedge with one O(2)Sm4 tetrahedra, and edges with two equivalent O(7)Sm3Mo tetrahedra. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to one Sm(1), one Sm(2), one Sm(3), and one Mo(1) atom. In the seventh O site, O(7) is bonded to one Sm(1), one Sm(2), one Sm(3), and one Mo(1) atom to form OSm3Mo tetrahedra that share corners with two equivalent O(1)Sm4 tetrahedra, corners with two equivalent O(2)Sm4 tetrahedra,  an edgeedge with one O(1)Sm4 tetrahedra,  an edgeedge with one O(2)Sm4 tetrahedra, and edges with two equivalent O(5)Sm3Mo trigonal pyramids.