Ba4Mg(CuO2)4 crystallizes in the monoclinic P2/m space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a body-centered cubic geometry to two equivalent O(3), two equivalent O(4), and four equivalent O(2) atoms. In the second Ba site, Ba(2) is bonded in a distorted body-centered cubic geometry to two equivalent O(3), two equivalent O(4), and four equivalent O(1) atoms. Mg(1) is bonded in a 4-coordinate geometry to four equivalent O(1) atoms. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a 4-coordinate geometry to one O(3), one O(4), and two equivalent O(1) atoms. In the second Cu site, Cu(2) is bonded in a square co-planar geometry to one O(3), one O(4), and two equivalent O(2) atoms. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 8-coordinate geometry to four equivalent Ba(2), two equivalent Mg(1), and two equivalent Cu(1) atoms. In the second O site, O(2) is bonded in a 6-coordinate geometry to four equivalent Ba(1) and two equivalent Cu(2) atoms. In the third O site, O(3) is bonded to two equivalent Ba(1), two equivalent Ba(2), one Cu(1), and one Cu(2) atom to form a mixture of edge, face, and corner-sharing OBa4Cu2 octahedra. The corner-sharing octahedral tilt angles range from 62-63°. In the fourth O site, O(4) is bonded to two equivalent Ba(1), two equivalent Ba(2), one Cu(1), and one Cu(2) atom to form a mixture of edge, face, and corner-sharing OBa4Cu2 octahedra. The corner-sharing octahedral tilt angles range from 62-63°.
Ba4Mg(CuO2)4 crystallizes in the monoclinic P2/m space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a body-centered cubic geometry to two equivalent O(3), two equivalent O(4), and four equivalent O(2) atoms. Both Ba(1)-O(3) bond lengths are 2.73 Å. Both Ba(1)-O(4) bond lengths are 2.73 Å. There are two shorter (2.85 Å) and two longer (2.93 Å) Ba(1)-O(2) bond lengths. In the second Ba site, Ba(2) is bonded in a distorted body-centered cubic geometry to two equivalent O(3), two equivalent O(4), and four equivalent O(1) atoms. Both Ba(2)-O(3) bond lengths are 2.68 Å. Both Ba(2)-O(4) bond lengths are 2.68 Å. There are two shorter (3.05 Å) and two longer (3.10 Å) Ba(2)-O(1) bond lengths. Mg(1) is bonded in a 4-coordinate geometry to four equivalent O(1) atoms. All Mg(1)-O(1) bond lengths are 2.20 Å. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a 4-coordinate geometry to one O(3), one O(4), and two equivalent O(1) atoms. The Cu(1)-O(3) bond length is 2.02 Å. The Cu(1)-O(4) bond length is 2.02 Å. There is one shorter (2.34 Å) and one longer (2.36 Å) Cu(1)-O(1) bond length. In the second Cu site, Cu(2) is bonded in a square co-planar geometry to one O(3), one O(4), and two equivalent O(2) atoms. The Cu(2)-O(3) bond length is 2.14 Å. The Cu(2)-O(4) bond length is 2.10 Å. There is one shorter (1.97 Å) and one longer (2.00 Å) Cu(2)-O(2) bond length. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 8-coordinate geometry to four equivalent Ba(2), two equivalent Mg(1), and two equivalent Cu(1) atoms. In the second O site, O(2) is bonded in a 6-coordinate geometry to four equivalent Ba(1) and two equivalent Cu(2) atoms. In the third O site, O(3) is bonded to two equivalent Ba(1), two equivalent Ba(2), one Cu(1), and one Cu(2) atom to form a mixture of edge, face, and corner-sharing OBa4Cu2 octahedra. The corner-sharing octahedral tilt angles range from 62-63°. In the fourth O site, O(4) is bonded to two equivalent Ba(1), two equivalent Ba(2), one Cu(1), and one Cu(2) atom to form a mixture of edge, face, and corner-sharing OBa4Cu2 octahedra. The corner-sharing octahedral tilt angles range from 62-63°.