Sm2InNbO7 crystallizes in the orthorhombic Imma space group. There are two inequivalent Sm sites. In the first Sm site, Sm(1) is bonded to two equivalent O(1), two equivalent O(2), and four equivalent O(4) atoms to form distorted SmO8 hexagonal bipyramids that share edges with two equivalent Sm(1)O8 hexagonal bipyramids, edges with two equivalent In(1)O6 octahedra, and edges with four equivalent Nb(1)O6 octahedra. In the second Sm site, Sm(2) is bonded in a body-centered cubic geometry to two equivalent O(1), two equivalent O(3), and four equivalent O(4) atoms. Nb(1) is bonded to two equivalent O(2) and four equivalent O(4) atoms to form NbO6 octahedra that share corners with two equivalent Nb(1)O6 octahedra, corners with four equivalent In(1)O6 octahedra, and edges with four equivalent Sm(1)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 38-53°. In(1) is bonded to two equivalent O(3) and four equivalent O(4) atoms to form InO6 octahedra that share corners with two equivalent In(1)O6 octahedra, corners with four equivalent Nb(1)O6 octahedra, and edges with two equivalent Sm(1)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 53-62°. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Sm(1) and two equivalent Sm(2) atoms to form OSm4 tetrahedra that share corners with two equivalent O(3)Sm2In2 tetrahedra, corners with four equivalent O(1)Sm4 tetrahedra, corners with eight equivalent O(4)Sm2NbIn tetrahedra,  an edgeedge with one O(3)Sm2In2 tetrahedra, and edges with four equivalent O(4)Sm2NbIn tetrahedra. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent Sm(1) and two equivalent Nb(1) atoms. In the third O site, O(3) is bonded to two equivalent Sm(2) and two equivalent In(1) atoms to form OSm2In2 tetrahedra that share corners with two equivalent O(1)Sm4 tetrahedra, corners with four equivalent O(3)Sm2In2 tetrahedra, corners with eight equivalent O(4)Sm2NbIn tetrahedra,  an edgeedge with one O(1)Sm4 tetrahedra, and edges with four equivalent O(4)Sm2NbIn tetrahedra. In the fourth O site, O(4) is bonded to one Sm(1), one Sm(2), one Nb(1), and one In(1) atom to form distorted OSm2NbIn tetrahedra that share corners with two equivalent O(3)Sm2In2 tetrahedra, corners with two equivalent O(1)Sm4 tetrahedra, corners with eight equivalent O(4)Sm2NbIn tetrahedra,  an edgeedge with one O(3)Sm2In2 tetrahedra,  an edgeedge with one O(1)Sm4 tetrahedra, and edges with two equivalent O(4)Sm2NbIn tetrahedra.
Sm2InNbO7 crystallizes in the orthorhombic Imma space group. There are two inequivalent Sm sites. In the first Sm site, Sm(1) is bonded to two equivalent O(1), two equivalent O(2), and four equivalent O(4) atoms to form distorted SmO8 hexagonal bipyramids that share edges with two equivalent Sm(1)O8 hexagonal bipyramids, edges with two equivalent In(1)O6 octahedra, and edges with four equivalent Nb(1)O6 octahedra. Both Sm(1)-O(1) bond lengths are 2.26 Å. Both Sm(1)-O(2) bond lengths are 2.73 Å. All Sm(1)-O(4) bond lengths are 2.52 Å. In the second Sm site, Sm(2) is bonded in a body-centered cubic geometry to two equivalent O(1), two equivalent O(3), and four equivalent O(4) atoms. Both Sm(2)-O(1) bond lengths are 2.35 Å. Both Sm(2)-O(3) bond lengths are 2.46 Å. All Sm(2)-O(4) bond lengths are 2.60 Å. Nb(1) is bonded to two equivalent O(2) and four equivalent O(4) atoms to form NbO6 octahedra that share corners with two equivalent Nb(1)O6 octahedra, corners with four equivalent In(1)O6 octahedra, and edges with four equivalent Sm(1)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 38-53°. Both Nb(1)-O(2) bond lengths are 2.02 Å. All Nb(1)-O(4) bond lengths are 2.01 Å. In(1) is bonded to two equivalent O(3) and four equivalent O(4) atoms to form InO6 octahedra that share corners with two equivalent In(1)O6 octahedra, corners with four equivalent Nb(1)O6 octahedra, and edges with two equivalent Sm(1)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 53-62°. Both In(1)-O(3) bond lengths are 2.16 Å. All In(1)-O(4) bond lengths are 2.20 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Sm(1) and two equivalent Sm(2) atoms to form OSm4 tetrahedra that share corners with two equivalent O(3)Sm2In2 tetrahedra, corners with four equivalent O(1)Sm4 tetrahedra, corners with eight equivalent O(4)Sm2NbIn tetrahedra,  an edgeedge with one O(3)Sm2In2 tetrahedra, and edges with four equivalent O(4)Sm2NbIn tetrahedra. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent Sm(1) and two equivalent Nb(1) atoms. In the third O site, O(3) is bonded to two equivalent Sm(2) and two equivalent In(1) atoms to form OSm2In2 tetrahedra that share corners with two equivalent O(1)Sm4 tetrahedra, corners with four equivalent O(3)Sm2In2 tetrahedra, corners with eight equivalent O(4)Sm2NbIn tetrahedra,  an edgeedge with one O(1)Sm4 tetrahedra, and edges with four equivalent O(4)Sm2NbIn tetrahedra. In the fourth O site, O(4) is bonded to one Sm(1), one Sm(2), one Nb(1), and one In(1) atom to form distorted OSm2NbIn tetrahedra that share corners with two equivalent O(3)Sm2In2 tetrahedra, corners with two equivalent O(1)Sm4 tetrahedra, corners with eight equivalent O(4)Sm2NbIn tetrahedra,  an edgeedge with one O(3)Sm2In2 tetrahedra,  an edgeedge with one O(1)Sm4 tetrahedra, and edges with two equivalent O(4)Sm2NbIn tetrahedra.