Ba2MgSmNbO6 crystallizes in the orthorhombic Immm space group. Ba(1) is bonded in a 9-coordinate geometry to one Mg(1), four equivalent O(1), and four equivalent O(2) atoms. Mg(1) is bonded in a distorted square co-planar geometry to two equivalent Ba(1) and four equivalent O(1) atoms. Sm(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form SmO6 octahedra that share corners with six equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-6°. Nb(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form NbO6 octahedra that share corners with six equivalent Sm(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-6°. There are two inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ba(1), one Mg(1), one Sm(1), and one Nb(1) atom to form a mixture of distorted edge, face, and corner-sharing OBa2SmMgNb trigonal bipyramids. In the second O site, O(2) is bonded in a 6-coordinate geometry to four equivalent Ba(1), one Sm(1), and one Nb(1) atom.
Ba2MgSmNbO6 crystallizes in the orthorhombic Immm space group. Ba(1) is bonded in a 9-coordinate geometry to one Mg(1), four equivalent O(1), and four equivalent O(2) atoms. The Ba(1)-Mg(1) bond length is 2.92 Å. All Ba(1)-O(1) bond lengths are 2.88 Å. There are two shorter (3.07 Å) and two longer (3.28 Å) Ba(1)-O(2) bond lengths. Mg(1) is bonded in a distorted square co-planar geometry to two equivalent Ba(1) and four equivalent O(1) atoms. All Mg(1)-O(1) bond lengths are 2.09 Å. Sm(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form SmO6 octahedra that share corners with six equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-6°. Both Sm(1)-O(2) bond lengths are 2.54 Å. All Sm(1)-O(1) bond lengths are 2.29 Å. Nb(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form NbO6 octahedra that share corners with six equivalent Sm(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-6°. Both Nb(1)-O(2) bond lengths are 2.09 Å. All Nb(1)-O(1) bond lengths are 2.12 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ba(1), one Mg(1), one Sm(1), and one Nb(1) atom to form a mixture of distorted edge, face, and corner-sharing OBa2SmMgNb trigonal bipyramids. In the second O site, O(2) is bonded in a 6-coordinate geometry to four equivalent Ba(1), one Sm(1), and one Nb(1) atom.