Li3Cu2O4 crystallizes in the monoclinic Cm space group. There are three inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(2), one O(3), and two equivalent O(4) atoms to form distorted LiO4 tetrahedra that share  a cornercorner with one Li(3)O6 octahedra, corners with two equivalent Li(1)O4 tetrahedra, edges with two equivalent Li(3)O6 octahedra, and edges with two equivalent Li(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 37°. In the second Li site, Li(2) is bonded to one O(1), one O(4), and two equivalent O(3) atoms to form distorted LiO4 tetrahedra that share  a cornercorner with one Li(3)O6 octahedra, corners with two equivalent Li(2)O4 tetrahedra, edges with two equivalent Li(3)O6 octahedra, and edges with two equivalent Li(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 36°. In the third Li site, Li(3) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(2) atoms to form distorted LiO6 octahedra that share  a cornercorner with one Li(1)O4 tetrahedra,  a cornercorner with one Li(2)O4 tetrahedra, edges with two equivalent Li(3)O6 octahedra, edges with two equivalent Li(1)O4 tetrahedra, and edges with two equivalent Li(2)O4 tetrahedra. 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(3) atoms. In the second Cu site, Cu(2) is bonded in a square co-planar geometry to two equivalent O(2) and two equivalent O(4) atoms. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Li(2), two equivalent Li(3), and two equivalent Cu(1) atoms to form OLi3Cu2 square pyramids that share corners with three equivalent O(4)Li4Cu2 octahedra, corners with two equivalent O(2)Li3Cu2 trigonal bipyramids, edges with two equivalent O(1)Li3Cu2 square pyramids, and  an edgeedge with one O(2)Li3Cu2 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 44-85°. In the second O site, O(2) is bonded to one Li(1), two equivalent Li(3), and two equivalent Cu(2) atoms to form OLi3Cu2 trigonal bipyramids that share corners with two equivalent O(4)Li4Cu2 octahedra, corners with two equivalent O(1)Li3Cu2 square pyramids, edges with three equivalent O(4)Li4Cu2 octahedra,  an edgeedge with one O(1)Li3Cu2 square pyramid, and edges with two equivalent O(2)Li3Cu2 trigonal bipyramids. The corner-sharing octahedral tilt angles are 3°. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Li(1), one Li(3), two equivalent Li(2), and two equivalent Cu(1) atoms. In the fourth O site, O(4) is bonded to one Li(2), one Li(3), two equivalent Li(1), and two equivalent Cu(2) atoms to form distorted OLi4Cu2 octahedra that share corners with three equivalent O(1)Li3Cu2 square pyramids, corners with two equivalent O(2)Li3Cu2 trigonal bipyramids, edges with two equivalent O(4)Li4Cu2 octahedra, and edges with three equivalent O(2)Li3Cu2 trigonal bipyramids.
Li3Cu2O4 crystallizes in the monoclinic Cm space group. There are three inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(2), one O(3), and two equivalent O(4) atoms to form distorted LiO4 tetrahedra that share  a cornercorner with one Li(3)O6 octahedra, corners with two equivalent Li(1)O4 tetrahedra, edges with two equivalent Li(3)O6 octahedra, and edges with two equivalent Li(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 37°. The Li(1)-O(2) bond length is 1.88 Å. The Li(1)-O(3) bond length is 1.93 Å. Both Li(1)-O(4) bond lengths are 1.94 Å. In the second Li site, Li(2) is bonded to one O(1), one O(4), and two equivalent O(3) atoms to form distorted LiO4 tetrahedra that share  a cornercorner with one Li(3)O6 octahedra, corners with two equivalent Li(2)O4 tetrahedra, edges with two equivalent Li(3)O6 octahedra, and edges with two equivalent Li(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 36°. The Li(2)-O(1) bond length is 1.88 Å. The Li(2)-O(4) bond length is 1.96 Å. Both Li(2)-O(3) bond lengths are 1.94 Å. In the third Li site, Li(3) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(2) atoms to form distorted LiO6 octahedra that share  a cornercorner with one Li(1)O4 tetrahedra,  a cornercorner with one Li(2)O4 tetrahedra, edges with two equivalent Li(3)O6 octahedra, edges with two equivalent Li(1)O4 tetrahedra, and edges with two equivalent Li(2)O4 tetrahedra. The Li(3)-O(3) bond length is 2.56 Å. The Li(3)-O(4) bond length is 2.42 Å. Both Li(3)-O(1) bond lengths are 2.05 Å. Both Li(3)-O(2) bond lengths are 2.06 Å. 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(3) atoms. Both Cu(1)-O(1) bond lengths are 1.88 Å. Both Cu(1)-O(3) bond lengths are 1.88 Å. In the second Cu site, Cu(2) is bonded in a square co-planar geometry to two equivalent O(2) and two equivalent O(4) atoms. Both Cu(2)-O(2) bond lengths are 1.88 Å. Both Cu(2)-O(4) bond lengths are 1.89 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Li(2), two equivalent Li(3), and two equivalent Cu(1) atoms to form OLi3Cu2 square pyramids that share corners with three equivalent O(4)Li4Cu2 octahedra, corners with two equivalent O(2)Li3Cu2 trigonal bipyramids, edges with two equivalent O(1)Li3Cu2 square pyramids, and  an edgeedge with one O(2)Li3Cu2 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 44-85°. In the second O site, O(2) is bonded to one Li(1), two equivalent Li(3), and two equivalent Cu(2) atoms to form OLi3Cu2 trigonal bipyramids that share corners with two equivalent O(4)Li4Cu2 octahedra, corners with two equivalent O(1)Li3Cu2 square pyramids, edges with three equivalent O(4)Li4Cu2 octahedra,  an edgeedge with one O(1)Li3Cu2 square pyramid, and edges with two equivalent O(2)Li3Cu2 trigonal bipyramids. The corner-sharing octahedral tilt angles are 3°. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Li(1), one Li(3), two equivalent Li(2), and two equivalent Cu(1) atoms. In the fourth O site, O(4) is bonded to one Li(2), one Li(3), two equivalent Li(1), and two equivalent Cu(2) atoms to form distorted OLi4Cu2 octahedra that share corners with three equivalent O(1)Li3Cu2 square pyramids, corners with two equivalent O(2)Li3Cu2 trigonal bipyramids, edges with two equivalent O(4)Li4Cu2 octahedra, and edges with three equivalent O(2)Li3Cu2 trigonal bipyramids.