Ba2MgSmNbO6 crystallizes in the trigonal R3m space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a distorted q6 geometry to three equivalent O(1) and six equivalent O(2) atoms. In the second Ba site, Ba(2) is bonded in a 3-coordinate geometry to three equivalent O(2) atoms. Mg(1) is bonded in a distorted trigonal non-coplanar geometry to three equivalent O(2) atoms. Sm(1) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form distorted SmO6 octahedra that share corners with six equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 4-7°. Nb(1) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form NbO6 octahedra that share corners with six equivalent Sm(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 4-7°. There are two inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to one Ba(1), one Sm(1), and one Nb(1) atom. In the second O site, O(2) is bonded in a 6-coordinate geometry to one Ba(2), two equivalent Ba(1), one Mg(1), one Sm(1), and one Nb(1) atom.
Ba2MgSmNbO6 crystallizes in the trigonal R3m space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a distorted q6 geometry to three equivalent O(1) and six equivalent O(2) atoms. All Ba(1)-O(1) bond lengths are 2.83 Å. All Ba(1)-O(2) bond lengths are 3.04 Å. In the second Ba site, Ba(2) is bonded in a 3-coordinate geometry to three equivalent O(2) atoms. All Ba(2)-O(2) bond lengths are 2.58 Å. Mg(1) is bonded in a distorted trigonal non-coplanar geometry to three equivalent O(2) atoms. All Mg(1)-O(2) bond lengths are 1.97 Å. Sm(1) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form distorted SmO6 octahedra that share corners with six equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 4-7°. All Sm(1)-O(1) bond lengths are 2.27 Å. All Sm(1)-O(2) bond lengths are 2.57 Å. Nb(1) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form NbO6 octahedra that share corners with six equivalent Sm(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 4-7°. All Nb(1)-O(1) bond lengths are 2.01 Å. All Nb(1)-O(2) bond lengths are 2.29 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to one Ba(1), one Sm(1), and one Nb(1) atom. In the second O site, O(2) is bonded in a 6-coordinate geometry to one Ba(2), two equivalent Ba(1), one Mg(1), one Sm(1), and one Nb(1) atom.