NaCu2O2 crystallizes in the orthorhombic Pnma space group. Na(1) is bonded to two equivalent O(2) and three equivalent O(1) atoms to form distorted edge-sharing NaO5 square pyramids. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a square co-planar geometry to two equivalent O(1) and two equivalent O(2) atoms. In the second Cu site, Cu(2) is bonded in a linear geometry to one O(1) and one O(2) atom. There are two inequivalent O sites. In the first O site, O(1) is bonded to three equivalent Na(1), one Cu(2), and two equivalent Cu(1) atoms to form ONa3Cu3 octahedra that share corners with seven equivalent O(2)Na2Cu3 square pyramids, edges with four equivalent O(1)Na3Cu3 octahedra, and edges with two equivalent O(2)Na2Cu3 square pyramids. In the second O site, O(2) is bonded to two equivalent Na(1), one Cu(2), and two equivalent Cu(1) atoms to form ONa2Cu3 square pyramids that share corners with seven equivalent O(1)Na3Cu3 octahedra, edges with two equivalent O(1)Na3Cu3 octahedra, and edges with two equivalent O(2)Na2Cu3 square pyramids. The corner-sharing octahedral tilt angles range from 0-76°.
NaCu2O2 crystallizes in the orthorhombic Pnma space group. Na(1) is bonded to two equivalent O(2) and three equivalent O(1) atoms to form distorted edge-sharing NaO5 square pyramids. Both Na(1)-O(2) bond lengths are 2.30 Å. There is one shorter (2.34 Å) and two longer (2.35 Å) Na(1)-O(1) bond lengths. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a square co-planar geometry to two equivalent O(1) and two equivalent O(2) atoms. Both Cu(1)-O(1) bond lengths are 1.99 Å. Both Cu(1)-O(2) bond lengths are 1.97 Å. In the second Cu site, Cu(2) is bonded in a linear geometry to one O(1) and one O(2) atom. The Cu(2)-O(1) bond length is 1.85 Å. The Cu(2)-O(2) bond length is 1.84 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded to three equivalent Na(1), one Cu(2), and two equivalent Cu(1) atoms to form ONa3Cu3 octahedra that share corners with seven equivalent O(2)Na2Cu3 square pyramids, edges with four equivalent O(1)Na3Cu3 octahedra, and edges with two equivalent O(2)Na2Cu3 square pyramids. In the second O site, O(2) is bonded to two equivalent Na(1), one Cu(2), and two equivalent Cu(1) atoms to form ONa2Cu3 square pyramids that share corners with seven equivalent O(1)Na3Cu3 octahedra, edges with two equivalent O(1)Na3Cu3 octahedra, and edges with two equivalent O(2)Na2Cu3 square pyramids. The corner-sharing octahedral tilt angles range from 0-76°.