Sr2MgSmTa(CuO4)2 crystallizes in the tetragonal P4/mmm space group. Sr(1) is bonded in a 8-coordinate geometry to four equivalent O(1) and four equivalent O(3) atoms. Mg(1) is bonded in a square co-planar geometry to four equivalent O(2) atoms. Sm(1) is bonded in a body-centered cubic geometry to eight equivalent O(1) atoms. Ta(1) is bonded to two equivalent O(3) and four equivalent O(2) atoms to form corner-sharing TaO6 octahedra. The corner-sharing octahedra are not tilted. Cu(1) is bonded in a rectangular see-saw-like geometry to four equivalent O(1) atoms. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Sr(1), two equivalent Sm(1), and two equivalent Cu(1) atoms to form a mixture of corner, face, and edge-sharing OSr2Sm2Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-68°. In the second O site, O(2) is bonded in a square co-planar geometry to two equivalent Mg(1) and two equivalent Ta(1) atoms. In the third O site, O(3) is bonded in a distorted single-bond geometry to four equivalent Sr(1) and one Ta(1) atom.
Sr2MgSmTa(CuO4)2 crystallizes in the tetragonal P4/mmm space group. Sr(1) is bonded in a 8-coordinate geometry to four equivalent O(1) and four equivalent O(3) atoms. All Sr(1)-O(1) bond lengths are 2.63 Å. All Sr(1)-O(3) bond lengths are 3.17 Å. Mg(1) is bonded in a square co-planar geometry to four equivalent O(2) atoms. All Mg(1)-O(2) bond lengths are 2.02 Å. Sm(1) is bonded in a body-centered cubic geometry to eight equivalent O(1) atoms. All Sm(1)-O(1) bond lengths are 2.55 Å. Ta(1) is bonded to two equivalent O(3) and four equivalent O(2) atoms to form corner-sharing TaO6 octahedra. The corner-sharing octahedra are not tilted. Both Ta(1)-O(3) bond lengths are 1.97 Å. All Ta(1)-O(2) bond lengths are 2.02 Å. Cu(1) is bonded in a rectangular see-saw-like geometry to four equivalent O(1) atoms. All Cu(1)-O(1) bond lengths are 2.02 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Sr(1), two equivalent Sm(1), and two equivalent Cu(1) atoms to form a mixture of corner, face, and edge-sharing OSr2Sm2Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-68°. In the second O site, O(2) is bonded in a square co-planar geometry to two equivalent Mg(1) and two equivalent Ta(1) atoms. In the third O site, O(3) is bonded in a distorted single-bond geometry to four equivalent Sr(1) and one Ta(1) atom.