Li3CuO3 crystallizes in the tetragonal P4_2/mnm space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form a mixture of distorted corner and edge-sharing LiO4 tetrahedra. In the second Li site, Li(2) is bonded to one O(1) and three equivalent O(2) atoms to form a mixture of distorted corner and edge-sharing LiO4 trigonal pyramids. Cu(1) is bonded in a rectangular see-saw-like geometry to two equivalent O(1) and two equivalent O(2) atoms. There are two inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Li(1), two equivalent Li(2), and two equivalent Cu(1) atoms to form distorted OLi4Cu2 octahedra that share corners with two equivalent O(1)Li4Cu2 octahedra, corners with two equivalent O(2)Li4Cu trigonal bipyramids,  an edgeedge with one O(1)Li4Cu2 octahedra, and edges with six equivalent O(2)Li4Cu trigonal bipyramids. The corner-sharing octahedral tilt angles are 47°. In the second O site, O(2) is bonded to one Li(1), three equivalent Li(2), and one Cu(1) atom to form OLi4Cu trigonal bipyramids that share  a cornercorner with one O(1)Li4Cu2 octahedra, corners with six equivalent O(2)Li4Cu trigonal bipyramids, edges with three equivalent O(1)Li4Cu2 octahedra, and  an edgeedge with one O(2)Li4Cu trigonal bipyramid. The corner-sharing octahedral tilt angles are 3°.
Li3CuO3 crystallizes in the tetragonal P4_2/mnm space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form a mixture of distorted corner and edge-sharing LiO4 tetrahedra. Both Li(1)-O(1) bond lengths are 1.94 Å. Both Li(1)-O(2) bond lengths are 1.91 Å. In the second Li site, Li(2) is bonded to one O(1) and three equivalent O(2) atoms to form a mixture of distorted corner and edge-sharing LiO4 trigonal pyramids. The Li(2)-O(1) bond length is 2.22 Å. There is one shorter (1.89 Å) and two longer (1.90 Å) Li(2)-O(2) bond lengths. Cu(1) is bonded in a rectangular see-saw-like geometry to two equivalent O(1) and two equivalent O(2) atoms. Both Cu(1)-O(1) bond lengths are 1.87 Å. Both Cu(1)-O(2) bond lengths are 1.81 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Li(1), two equivalent Li(2), and two equivalent Cu(1) atoms to form distorted OLi4Cu2 octahedra that share corners with two equivalent O(1)Li4Cu2 octahedra, corners with two equivalent O(2)Li4Cu trigonal bipyramids,  an edgeedge with one O(1)Li4Cu2 octahedra, and edges with six equivalent O(2)Li4Cu trigonal bipyramids. The corner-sharing octahedral tilt angles are 47°. In the second O site, O(2) is bonded to one Li(1), three equivalent Li(2), and one Cu(1) atom to form OLi4Cu trigonal bipyramids that share  a cornercorner with one O(1)Li4Cu2 octahedra, corners with six equivalent O(2)Li4Cu trigonal bipyramids, edges with three equivalent O(1)Li4Cu2 octahedra, and  an edgeedge with one O(2)Li4Cu trigonal bipyramid. The corner-sharing octahedral tilt angles are 3°.