Li3Cu2O4 crystallizes in the monoclinic C2/m space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(2) and three equivalent O(1) atoms to form distorted LiO4 tetrahedra that share  a cornercorner with one Li(2)O6 octahedra, corners with two equivalent Li(1)O4 tetrahedra, edges with two equivalent Li(2)O6 octahedra, and edges with two equivalent Li(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 36°. In the second Li site, Li(2) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form distorted LiO6 octahedra that share corners with two equivalent Li(1)O4 tetrahedra, edges with two equivalent Li(2)O6 octahedra, and edges with four equivalent Li(1)O4 tetrahedra. Cu(1) is bonded in a square co-planar 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 one Li(2), three equivalent Li(1), and two equivalent Cu(1) atoms to form distorted OLi4Cu2 octahedra that share  a cornercorner with one O(1)Li4Cu2 octahedra, corners with five equivalent O(2)Li3Cu2 square pyramids, edges with four equivalent O(1)Li4Cu2 octahedra, and edges with three equivalent O(2)Li3Cu2 square pyramids. The corner-sharing octahedra are not tilted. In the second O site, O(2) is bonded to one Li(1), two equivalent Li(2), and two equivalent Cu(1) atoms to form distorted OLi3Cu2 square pyramids that share corners with five equivalent O(1)Li4Cu2 octahedra, corners with two equivalent O(2)Li3Cu2 square pyramids, edges with three equivalent O(1)Li4Cu2 octahedra, and edges with three equivalent O(2)Li3Cu2 square pyramids. The corner-sharing octahedral tilt angles range from 3-87°.
Li3Cu2O4 crystallizes in the monoclinic C2/m space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(2) and three equivalent O(1) atoms to form distorted LiO4 tetrahedra that share  a cornercorner with one Li(2)O6 octahedra, corners with two equivalent Li(1)O4 tetrahedra, edges with two equivalent Li(2)O6 octahedra, and edges with two equivalent Li(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 36°. The Li(1)-O(2) bond length is 1.88 Å. All Li(1)-O(1) bond lengths are 1.94 Å. In the second Li site, Li(2) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form distorted LiO6 octahedra that share corners with two equivalent Li(1)O4 tetrahedra, edges with two equivalent Li(2)O6 octahedra, and edges with four equivalent Li(1)O4 tetrahedra. Both Li(2)-O(1) bond lengths are 2.48 Å. All Li(2)-O(2) bond lengths are 2.06 Å. 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 1.89 Å. Both Cu(1)-O(2) bond lengths are 1.88 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded to one Li(2), three equivalent Li(1), and two equivalent Cu(1) atoms to form distorted OLi4Cu2 octahedra that share  a cornercorner with one O(1)Li4Cu2 octahedra, corners with five equivalent O(2)Li3Cu2 square pyramids, edges with four equivalent O(1)Li4Cu2 octahedra, and edges with three equivalent O(2)Li3Cu2 square pyramids. The corner-sharing octahedra are not tilted. In the second O site, O(2) is bonded to one Li(1), two equivalent Li(2), and two equivalent Cu(1) atoms to form distorted OLi3Cu2 square pyramids that share corners with five equivalent O(1)Li4Cu2 octahedra, corners with two equivalent O(2)Li3Cu2 square pyramids, edges with three equivalent O(1)Li4Cu2 octahedra, and edges with three equivalent O(2)Li3Cu2 square pyramids. The corner-sharing octahedral tilt angles range from 3-87°.