Sm3NbO7 crystallizes in the triclinic P-1 space group. There are three inequivalent Sm sites. In the first Sm site, Sm(1) is bonded to one O(3), one O(4), one O(7), two equivalent O(2), and two equivalent O(6) atoms to form distorted SmO7 pentagonal bipyramids that share  a cornercorner with one Nb(1)O6 octahedra,  a cornercorner with one Nb(2)O6 octahedra,  a cornercorner with one Sm(3)O7 pentagonal bipyramid,  an edgeedge with one Nb(1)O6 octahedra, edges with two equivalent Sm(1)O7 pentagonal bipyramids, and edges with two equivalent Sm(3)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 48-50°. In the second Sm site, Sm(2) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(6), two equivalent O(4), and two equivalent O(7) atoms. In the third Sm site, Sm(3) is bonded to one O(5), one O(6), one O(7), two equivalent O(1), and two equivalent O(3) atoms to form distorted SmO7 pentagonal bipyramids that share  a cornercorner with one Nb(1)O6 octahedra,  a cornercorner with one Nb(2)O6 octahedra,  a cornercorner with one Sm(1)O7 pentagonal bipyramid,  an edgeedge with one Nb(1)O6 octahedra,  an edgeedge with one Nb(2)O6 octahedra, edges with two equivalent Sm(1)O7 pentagonal bipyramids, and edges with two equivalent Sm(3)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 44-45°. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms to form NbO6 octahedra that share corners with two equivalent Nb(2)O6 octahedra, corners with two equivalent Sm(1)O7 pentagonal bipyramids, corners with two equivalent Sm(3)O7 pentagonal bipyramids, edges with two equivalent Sm(1)O7 pentagonal bipyramids, and edges with two equivalent Sm(3)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 32°. In the second Nb site, Nb(2) is bonded to two equivalent O(1), two equivalent O(4), and two equivalent O(5) atoms to form NbO6 octahedra that share corners with two equivalent Nb(1)O6 octahedra, corners with two equivalent Sm(1)O7 pentagonal bipyramids, corners with two equivalent Sm(3)O7 pentagonal bipyramids, and edges with two equivalent Sm(3)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 32°. There are seven inequivalent O sites. In the first O site, O(1) is bonded to one Sm(2), two equivalent Sm(3), and one Nb(2) atom to form distorted OSm3Nb tetrahedra that share  a cornercorner with one O(1)Sm3Nb tetrahedra,  a cornercorner with one O(6)Sm4 tetrahedra, corners with two equivalent O(4)Sm3Nb tetrahedra, corners with two equivalent O(7)Sm4 tetrahedra, corners with four equivalent O(3)Sm3Nb tetrahedra,  an edgeedge with one O(1)Sm3Nb tetrahedra,  an edgeedge with one O(4)Sm3Nb tetrahedra,  an edgeedge with one O(6)Sm4 tetrahedra, and  an edgeedge with one O(7)Sm4 tetrahedra. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Sm(2), two equivalent Sm(1), and one Nb(1) atom. In the third O site, O(3) is bonded to one Sm(1), two equivalent Sm(3), and one Nb(1) atom to form distorted OSm3Nb tetrahedra that share  a cornercorner with one O(3)Sm3Nb tetrahedra,  a cornercorner with one O(4)Sm3Nb tetrahedra,  a cornercorner with one O(7)Sm4 tetrahedra, corners with two equivalent O(6)Sm4 tetrahedra, corners with four equivalent O(1)Sm3Nb tetrahedra,  an edgeedge with one O(3)Sm3Nb tetrahedra,  an edgeedge with one O(6)Sm4 tetrahedra, and  an edgeedge with one O(7)Sm4 tetrahedra. In the fourth O site, O(4) is bonded to one Sm(1), two equivalent Sm(2), and one Nb(2) atom to form distorted OSm3Nb tetrahedra that share  a cornercorner with one O(3)Sm3Nb tetrahedra,  a cornercorner with one O(4)Sm3Nb tetrahedra, corners with two equivalent O(1)Sm3Nb tetrahedra, corners with three equivalent O(7)Sm4 tetrahedra, corners with four equivalent O(6)Sm4 tetrahedra,  an edgeedge with one O(1)Sm3Nb tetrahedra,  an edgeedge with one O(4)Sm3Nb tetrahedra, and  an edgeedge with one O(7)Sm4 tetrahedra. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Sm(3), one Nb(1), and one Nb(2) atom. In the sixth O site, O(6) is bonded to one Sm(2), one Sm(3), and two equivalent Sm(1) atoms to form OSm4 tetrahedra that share  a cornercorner with one O(1)Sm3Nb tetrahedra, corners with two equivalent O(3)Sm3Nb tetrahedra, corners with three equivalent O(7)Sm4 tetrahedra, corners with four equivalent O(4)Sm3Nb tetrahedra,  an edgeedge with one O(1)Sm3Nb tetrahedra,  an edgeedge with one O(3)Sm3Nb tetrahedra,  an edgeedge with one O(6)Sm4 tetrahedra, and  an edgeedge with one O(7)Sm4 tetrahedra. In the seventh O site, O(7) is bonded to one Sm(1), one Sm(3), and two equivalent Sm(2) atoms to form OSm4 tetrahedra that share  a cornercorner with one O(3)Sm3Nb tetrahedra, corners with two equivalent O(1)Sm3Nb tetrahedra, corners with three equivalent O(4)Sm3Nb tetrahedra, corners with three equivalent O(6)Sm4 tetrahedra,  an edgeedge with one O(1)Sm3Nb tetrahedra,  an edgeedge with one O(3)Sm3Nb tetrahedra,  an edgeedge with one O(4)Sm3Nb tetrahedra,  an edgeedge with one O(6)Sm4 tetrahedra, and  an edgeedge with one O(7)Sm4 tetrahedra.
Sm3NbO7 crystallizes in the triclinic P-1 space group. There are three inequivalent Sm sites. In the first Sm site, Sm(1) is bonded to one O(3), one O(4), one O(7), two equivalent O(2), and two equivalent O(6) atoms to form distorted SmO7 pentagonal bipyramids that share  a cornercorner with one Nb(1)O6 octahedra,  a cornercorner with one Nb(2)O6 octahedra,  a cornercorner with one Sm(3)O7 pentagonal bipyramid,  an edgeedge with one Nb(1)O6 octahedra, edges with two equivalent Sm(1)O7 pentagonal bipyramids, and edges with two equivalent Sm(3)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 48-50°. The Sm(1)-O(3) bond length is 2.48 Å. The Sm(1)-O(4) bond length is 2.43 Å. The Sm(1)-O(7) bond length is 2.34 Å. There is one shorter (2.42 Å) and one longer (2.50 Å) Sm(1)-O(2) bond length. There is one shorter (2.34 Å) and one longer (2.38 Å) Sm(1)-O(6) bond length. In the second Sm site, Sm(2) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(6), two equivalent O(4), and two equivalent O(7) atoms. The Sm(2)-O(1) bond length is 2.46 Å. The Sm(2)-O(2) bond length is 2.75 Å. The Sm(2)-O(6) bond length is 2.32 Å. There is one shorter (2.45 Å) and one longer (2.65 Å) Sm(2)-O(4) bond length. There is one shorter (2.27 Å) and one longer (2.31 Å) Sm(2)-O(7) bond length. In the third Sm site, Sm(3) is bonded to one O(5), one O(6), one O(7), two equivalent O(1), and two equivalent O(3) atoms to form distorted SmO7 pentagonal bipyramids that share  a cornercorner with one Nb(1)O6 octahedra,  a cornercorner with one Nb(2)O6 octahedra,  a cornercorner with one Sm(1)O7 pentagonal bipyramid,  an edgeedge with one Nb(1)O6 octahedra,  an edgeedge with one Nb(2)O6 octahedra, edges with two equivalent Sm(1)O7 pentagonal bipyramids, and edges with two equivalent Sm(3)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 44-45°. The Sm(3)-O(5) bond length is 2.44 Å. The Sm(3)-O(6) bond length is 2.25 Å. The Sm(3)-O(7) bond length is 2.25 Å. There is one shorter (2.38 Å) and one longer (2.45 Å) Sm(3)-O(1) bond length. There is one shorter (2.36 Å) and one longer (2.43 Å) Sm(3)-O(3) bond length. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms to form NbO6 octahedra that share corners with two equivalent Nb(2)O6 octahedra, corners with two equivalent Sm(1)O7 pentagonal bipyramids, corners with two equivalent Sm(3)O7 pentagonal bipyramids, edges with two equivalent Sm(1)O7 pentagonal bipyramids, and edges with two equivalent Sm(3)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 32°. Both Nb(1)-O(2) bond lengths are 2.02 Å. Both Nb(1)-O(3) bond lengths are 2.00 Å. Both Nb(1)-O(5) bond lengths are 2.02 Å. In the second Nb site, Nb(2) is bonded to two equivalent O(1), two equivalent O(4), and two equivalent O(5) atoms to form NbO6 octahedra that share corners with two equivalent Nb(1)O6 octahedra, corners with two equivalent Sm(1)O7 pentagonal bipyramids, corners with two equivalent Sm(3)O7 pentagonal bipyramids, and edges with two equivalent Sm(3)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 32°. Both Nb(2)-O(1) bond lengths are 1.99 Å. Both Nb(2)-O(4) bond lengths are 2.06 Å. Both Nb(2)-O(5) bond lengths are 2.00 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded to one Sm(2), two equivalent Sm(3), and one Nb(2) atom to form distorted OSm3Nb tetrahedra that share  a cornercorner with one O(1)Sm3Nb tetrahedra,  a cornercorner with one O(6)Sm4 tetrahedra, corners with two equivalent O(4)Sm3Nb tetrahedra, corners with two equivalent O(7)Sm4 tetrahedra, corners with four equivalent O(3)Sm3Nb tetrahedra,  an edgeedge with one O(1)Sm3Nb tetrahedra,  an edgeedge with one O(4)Sm3Nb tetrahedra,  an edgeedge with one O(6)Sm4 tetrahedra, and  an edgeedge with one O(7)Sm4 tetrahedra. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Sm(2), two equivalent Sm(1), and one Nb(1) atom. In the third O site, O(3) is bonded to one Sm(1), two equivalent Sm(3), and one Nb(1) atom to form distorted OSm3Nb tetrahedra that share  a cornercorner with one O(3)Sm3Nb tetrahedra,  a cornercorner with one O(4)Sm3Nb tetrahedra,  a cornercorner with one O(7)Sm4 tetrahedra, corners with two equivalent O(6)Sm4 tetrahedra, corners with four equivalent O(1)Sm3Nb tetrahedra,  an edgeedge with one O(3)Sm3Nb tetrahedra,  an edgeedge with one O(6)Sm4 tetrahedra, and  an edgeedge with one O(7)Sm4 tetrahedra. In the fourth O site, O(4) is bonded to one Sm(1), two equivalent Sm(2), and one Nb(2) atom to form distorted OSm3Nb tetrahedra that share  a cornercorner with one O(3)Sm3Nb tetrahedra,  a cornercorner with one O(4)Sm3Nb tetrahedra, corners with two equivalent O(1)Sm3Nb tetrahedra, corners with three equivalent O(7)Sm4 tetrahedra, corners with four equivalent O(6)Sm4 tetrahedra,  an edgeedge with one O(1)Sm3Nb tetrahedra,  an edgeedge with one O(4)Sm3Nb tetrahedra, and  an edgeedge with one O(7)Sm4 tetrahedra. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Sm(3), one Nb(1), and one Nb(2) atom. In the sixth O site, O(6) is bonded to one Sm(2), one Sm(3), and two equivalent Sm(1) atoms to form OSm4 tetrahedra that share  a cornercorner with one O(1)Sm3Nb tetrahedra, corners with two equivalent O(3)Sm3Nb tetrahedra, corners with three equivalent O(7)Sm4 tetrahedra, corners with four equivalent O(4)Sm3Nb tetrahedra,  an edgeedge with one O(1)Sm3Nb tetrahedra,  an edgeedge with one O(3)Sm3Nb tetrahedra,  an edgeedge with one O(6)Sm4 tetrahedra, and  an edgeedge with one O(7)Sm4 tetrahedra. In the seventh O site, O(7) is bonded to one Sm(1), one Sm(3), and two equivalent Sm(2) atoms to form OSm4 tetrahedra that share  a cornercorner with one O(3)Sm3Nb tetrahedra, corners with two equivalent O(1)Sm3Nb tetrahedra, corners with three equivalent O(4)Sm3Nb tetrahedra, corners with three equivalent O(6)Sm4 tetrahedra,  an edgeedge with one O(1)Sm3Nb tetrahedra,  an edgeedge with one O(3)Sm3Nb tetrahedra,  an edgeedge with one O(4)Sm3Nb tetrahedra,  an edgeedge with one O(6)Sm4 tetrahedra, and  an edgeedge with one O(7)Sm4 tetrahedra.