Cu4O3 crystallizes in the tetragonal P4/nmm space group. There are four inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one O(2) and four equivalent O(1) atoms to form distorted corner-sharing CuO5 square pyramids. In the second Cu site, Cu(2) is bonded in a linear geometry to two equivalent O(1) atoms. In the third Cu site, Cu(3) is bonded in a rectangular see-saw-like geometry to four equivalent O(2) atoms. In the fourth Cu site, Cu(4) is bonded in a rectangular see-saw-like geometry to four equivalent O(1) atoms. There are two inequivalent O sites. In the first O site, O(1) is bonded to one Cu(2), two equivalent Cu(1), and two equivalent Cu(4) atoms to form a mixture of corner and edge-sharing OCu5 square pyramids. In the second O site, O(2) is bonded to one Cu(1) and four equivalent Cu(3) atoms to form a mixture of corner and edge-sharing OCu5 square pyramids.
Cu4O3 crystallizes in the tetragonal P4/nmm space group. There are four inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one O(2) and four equivalent O(1) atoms to form distorted corner-sharing CuO5 square pyramids. The Cu(1)-O(2) bond length is 2.40 Å. All Cu(1)-O(1) bond lengths are 2.05 Å. In the second Cu site, Cu(2) is bonded in a linear geometry to two equivalent O(1) atoms. Both Cu(2)-O(1) bond lengths are 1.90 Å. In the third Cu site, Cu(3) is bonded in a rectangular see-saw-like geometry to four equivalent O(2) atoms. All Cu(3)-O(2) bond lengths are 2.03 Å. In the fourth Cu site, Cu(4) is bonded in a rectangular see-saw-like geometry to four equivalent O(1) atoms. All Cu(4)-O(1) bond lengths are 2.02 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded to one Cu(2), two equivalent Cu(1), and two equivalent Cu(4) atoms to form a mixture of corner and edge-sharing OCu5 square pyramids. In the second O site, O(2) is bonded to one Cu(1) and four equivalent Cu(3) atoms to form a mixture of corner and edge-sharing OCu5 square pyramids.