SrEuLaNbO6 crystallizes in the tetragonal P42_12 space group. Sr(1) is bonded in a distorted body-centered cubic geometry to four equivalent O(1) and four equivalent O(3) atoms. Eu(1) is bonded in a distorted body-centered cubic geometry to four equivalent O(2) and four equivalent O(3) atoms. La(1) is bonded to one O(1), one O(2), and four equivalent O(3) atoms to form LaO6 octahedra that share corners with six equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-35°. Nb(1) is bonded to one O(1), one O(2), and four equivalent O(3) atoms to form NbO6 octahedra that share corners with six equivalent La(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-35°. There are three inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Sr(1), one La(1), and one Nb(1) atom to form distorted OSr4LaNb octahedra that share corners with four equivalent O(1)Sr4LaNb octahedra, corners with eight equivalent O(3)SrLaEuNb tetrahedra, edges with four equivalent O(1)Sr4LaNb octahedra, and edges with eight equivalent O(3)SrLaEuNb tetrahedra. The corner-sharing octahedral tilt angles are 6°. In the second O site, O(2) is bonded in a distorted linear geometry to four equivalent Eu(1), one La(1), and one Nb(1) atom. In the third O site, O(3) is bonded to one Sr(1), one Eu(1), one La(1), and one Nb(1) atom to form distorted OSrLaEuNb tetrahedra that share corners with two equivalent O(1)Sr4LaNb octahedra, corners with ten equivalent O(3)SrLaEuNb tetrahedra, edges with two equivalent O(1)Sr4LaNb octahedra, and  an edgeedge with one O(3)SrLaEuNb tetrahedra. The corner-sharing octahedral tilt angles range from 67-68°.
SrEuLaNbO6 crystallizes in the tetragonal P42_12 space group. Sr(1) is bonded in a distorted body-centered cubic geometry to four equivalent O(1) and four equivalent O(3) atoms. All Sr(1)-O(1) bond lengths are 2.99 Å. All Sr(1)-O(3) bond lengths are 2.65 Å. Eu(1) is bonded in a distorted body-centered cubic geometry to four equivalent O(2) and four equivalent O(3) atoms. All Eu(1)-O(2) bond lengths are 2.99 Å. All Eu(1)-O(3) bond lengths are 2.61 Å. La(1) is bonded to one O(1), one O(2), and four equivalent O(3) atoms to form LaO6 octahedra that share corners with six equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-35°. The La(1)-O(1) bond length is 2.35 Å. The La(1)-O(2) bond length is 2.33 Å. All La(1)-O(3) bond lengths are 2.39 Å. Nb(1) is bonded to one O(1), one O(2), and four equivalent O(3) atoms to form NbO6 octahedra that share corners with six equivalent La(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-35°. The Nb(1)-O(1) bond length is 2.04 Å. The Nb(1)-O(2) bond length is 2.03 Å. All Nb(1)-O(3) bond lengths are 2.03 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Sr(1), one La(1), and one Nb(1) atom to form distorted OSr4LaNb octahedra that share corners with four equivalent O(1)Sr4LaNb octahedra, corners with eight equivalent O(3)SrLaEuNb tetrahedra, edges with four equivalent O(1)Sr4LaNb octahedra, and edges with eight equivalent O(3)SrLaEuNb tetrahedra. The corner-sharing octahedral tilt angles are 6°. In the second O site, O(2) is bonded in a distorted linear geometry to four equivalent Eu(1), one La(1), and one Nb(1) atom. In the third O site, O(3) is bonded to one Sr(1), one Eu(1), one La(1), and one Nb(1) atom to form distorted OSrLaEuNb tetrahedra that share corners with two equivalent O(1)Sr4LaNb octahedra, corners with ten equivalent O(3)SrLaEuNb tetrahedra, edges with two equivalent O(1)Sr4LaNb octahedra, and  an edgeedge with one O(3)SrLaEuNb tetrahedra. The corner-sharing octahedral tilt angles range from 67-68°.