GdBa2Cu4O8 crystallizes in the orthorhombic Cmmm space group. Ba(1) is bonded in a 10-coordinate geometry to two equivalent O(2), two equivalent O(3), two equivalent O(4), and four equivalent O(1) atoms. Gd(1) is bonded in a body-centered cubic geometry to four equivalent O(2) and four equivalent O(4) atoms. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one O(1), two equivalent O(2), and two equivalent O(4) atoms to form corner-sharing CuO5 square pyramids. In the second Cu site, Cu(2) is bonded in a square co-planar geometry to one O(1) and three equivalent O(3) atoms. There are four inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Ba(1), one Cu(1), and one Cu(2) atom to form a mixture of distorted corner and edge-sharing OBa4Cu2 octahedra. The corner-sharing octahedral tilt angles are 11°. In the second O site, O(2) is bonded in a 6-coordinate geometry to two equivalent Ba(1), two equivalent Gd(1), and two equivalent Cu(1) atoms. In the third O site, O(3) is bonded in a distorted T-shaped geometry to two equivalent Ba(1) and three equivalent Cu(2) atoms. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to two equivalent Ba(1), two equivalent Gd(1), and two equivalent Cu(1) atoms.
GdBa2Cu4O8 crystallizes in the orthorhombic Cmmm space group. Ba(1) is bonded in a 10-coordinate geometry to two equivalent O(2), two equivalent O(3), two equivalent O(4), and four equivalent O(1) atoms. Both Ba(1)-O(2) bond lengths are 2.99 Å. Both Ba(1)-O(3) bond lengths are 2.99 Å. Both Ba(1)-O(4) bond lengths are 2.99 Å. All Ba(1)-O(1) bond lengths are 2.78 Å. Gd(1) is bonded in a body-centered cubic geometry to four equivalent O(2) and four equivalent O(4) atoms. All Gd(1)-O(2) bond lengths are 2.42 Å. All Gd(1)-O(4) bond lengths are 2.43 Å. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one O(1), two equivalent O(2), and two equivalent O(4) atoms to form corner-sharing CuO5 square pyramids. The Cu(1)-O(1) bond length is 2.29 Å. Both Cu(1)-O(2) bond lengths are 1.97 Å. Both Cu(1)-O(4) bond lengths are 1.97 Å. In the second Cu site, Cu(2) is bonded in a square co-planar geometry to one O(1) and three equivalent O(3) atoms. The Cu(2)-O(1) bond length is 1.84 Å. There is one shorter (1.90 Å) and two longer (1.96 Å) Cu(2)-O(3) bond lengths. There are four inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Ba(1), one Cu(1), and one Cu(2) atom to form a mixture of distorted corner and edge-sharing OBa4Cu2 octahedra. The corner-sharing octahedral tilt angles are 11°. In the second O site, O(2) is bonded in a 6-coordinate geometry to two equivalent Ba(1), two equivalent Gd(1), and two equivalent Cu(1) atoms. In the third O site, O(3) is bonded in a distorted T-shaped geometry to two equivalent Ba(1) and three equivalent Cu(2) atoms. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to two equivalent Ba(1), two equivalent Gd(1), and two equivalent Cu(1) atoms.