Eu2ScNbO7 crystallizes in the orthorhombic Imma space group. There are two inequivalent Eu sites. In the first Eu site, Eu(1) is bonded to two equivalent O(1), two equivalent O(2), and four equivalent O(4) atoms to form distorted EuO8 hexagonal bipyramids that share edges with two equivalent Eu(1)O8 hexagonal bipyramids, edges with two equivalent Sc(1)O6 octahedra, and edges with four equivalent Nb(1)O6 octahedra. In the second Eu site, Eu(2) is bonded in a body-centered cubic geometry to two equivalent O(1), two equivalent O(3), and four equivalent O(4) atoms. Sc(1) is bonded to two equivalent O(3) and four equivalent O(4) atoms to form ScO6 octahedra that share corners with two equivalent Sc(1)O6 octahedra, corners with four equivalent Nb(1)O6 octahedra, and edges with two equivalent Eu(1)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 49-58°. 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 Sc(1)O6 octahedra, and edges with four equivalent Eu(1)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 42-49°. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Eu(1) and two equivalent Eu(2) atoms to form OEu4 tetrahedra that share corners with two equivalent O(3)Eu2Sc2 tetrahedra, corners with four equivalent O(1)Eu4 tetrahedra, and  an edgeedge with one O(3)Eu2Sc2 tetrahedra. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent Eu(1) and two equivalent Nb(1) atoms. In the third O site, O(3) is bonded to two equivalent Eu(2) and two equivalent Sc(1) atoms to form OEu2Sc2 tetrahedra that share corners with two equivalent O(1)Eu4 tetrahedra, corners with four equivalent O(3)Eu2Sc2 tetrahedra, and  an edgeedge with one O(1)Eu4 tetrahedra. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Eu(1), one Eu(2), one Sc(1), and one Nb(1) atom.
Eu2ScNbO7 crystallizes in the orthorhombic Imma space group. There are two inequivalent Eu sites. In the first Eu site, Eu(1) is bonded to two equivalent O(1), two equivalent O(2), and four equivalent O(4) atoms to form distorted EuO8 hexagonal bipyramids that share edges with two equivalent Eu(1)O8 hexagonal bipyramids, edges with two equivalent Sc(1)O6 octahedra, and edges with four equivalent Nb(1)O6 octahedra. Both Eu(1)-O(1) bond lengths are 2.26 Å. Both Eu(1)-O(2) bond lengths are 2.68 Å. All Eu(1)-O(4) bond lengths are 2.58 Å. In the second Eu site, Eu(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 Eu(2)-O(1) bond lengths are 2.33 Å. Both Eu(2)-O(3) bond lengths are 2.49 Å. All Eu(2)-O(4) bond lengths are 2.63 Å. Sc(1) is bonded to two equivalent O(3) and four equivalent O(4) atoms to form ScO6 octahedra that share corners with two equivalent Sc(1)O6 octahedra, corners with four equivalent Nb(1)O6 octahedra, and edges with two equivalent Eu(1)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 49-58°. Both Sc(1)-O(3) bond lengths are 2.13 Å. All Sc(1)-O(4) bond lengths are 2.11 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 Sc(1)O6 octahedra, and edges with four equivalent Eu(1)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 42-49°. Both Nb(1)-O(2) bond lengths are 2.02 Å. All Nb(1)-O(4) bond lengths are 2.00 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Eu(1) and two equivalent Eu(2) atoms to form OEu4 tetrahedra that share corners with two equivalent O(3)Eu2Sc2 tetrahedra, corners with four equivalent O(1)Eu4 tetrahedra, and  an edgeedge with one O(3)Eu2Sc2 tetrahedra. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent Eu(1) and two equivalent Nb(1) atoms. In the third O site, O(3) is bonded to two equivalent Eu(2) and two equivalent Sc(1) atoms to form OEu2Sc2 tetrahedra that share corners with two equivalent O(1)Eu4 tetrahedra, corners with four equivalent O(3)Eu2Sc2 tetrahedra, and  an edgeedge with one O(1)Eu4 tetrahedra. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Eu(1), one Eu(2), one Sc(1), and one Nb(1) atom.