Sr2GdCu2HgO7 crystallizes in the tetragonal P4/mmm space group. Sr(1) is bonded in a 9-coordinate geometry to one O(3), four equivalent O(1), and four equivalent O(2) atoms. Gd(1) is bonded in a body-centered cubic geometry to eight equivalent O(2) atoms. Cu(1) is bonded to one O(1) and four equivalent O(2) atoms to form corner-sharing CuO5 square pyramids. Hg(1) is bonded in a distorted linear geometry to two equivalent O(1) atoms. There are three inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Sr(1), one Cu(1), and one Hg(1) atom to form a mixture of edge and corner-sharing OSr4CuHg octahedra. The corner-sharing octahedral tilt angles range from 0-12°. In the second O site, O(2) is bonded in a 6-coordinate geometry to two equivalent Sr(1), two equivalent Gd(1), and two equivalent Cu(1) atoms. In the third O site, O(3) is bonded in a distorted linear geometry to two equivalent Sr(1) atoms.
Sr2GdCu2HgO7 crystallizes in the tetragonal P4/mmm space group. Sr(1) is bonded in a 9-coordinate geometry to one O(3), four equivalent O(1), and four equivalent O(2) atoms. The Sr(1)-O(3) bond length is 2.43 Å. All Sr(1)-O(1) bond lengths are 2.73 Å. All Sr(1)-O(2) bond lengths are 2.92 Å. Gd(1) is bonded in a body-centered cubic geometry to eight equivalent O(2) atoms. All Gd(1)-O(2) bond lengths are 2.42 Å. Cu(1) is bonded to one O(1) and four equivalent O(2) atoms to form corner-sharing CuO5 square pyramids. The Cu(1)-O(1) bond length is 2.20 Å. All Cu(1)-O(2) bond lengths are 1.94 Å. Hg(1) is bonded in a distorted linear geometry to two equivalent O(1) atoms. Both Hg(1)-O(1) bond lengths are 2.14 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Sr(1), one Cu(1), and one Hg(1) atom to form a mixture of edge and corner-sharing OSr4CuHg octahedra. The corner-sharing octahedral tilt angles range from 0-12°. In the second O site, O(2) is bonded in a 6-coordinate geometry to two equivalent Sr(1), two equivalent Gd(1), and two equivalent Cu(1) atoms. In the third O site, O(3) is bonded in a distorted linear geometry to two equivalent Sr(1) atoms.