Li4Fe2Cu3O10 crystallizes in the triclinic P-1 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(1), one O(5), two equivalent O(3), and two equivalent O(4) atoms to form distorted LiO6 octahedra that share corners with two equivalent Fe(1)O6 octahedra,  an edgeedge with one Cu(1)O6 octahedra, edges with two equivalent Li(1)O6 octahedra, edges with three equivalent Li(2)O6 octahedra, and edges with three equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-18°. In the second Li site, Li(2) is bonded to one O(1), one O(3), one O(4), one O(5), and two equivalent O(2) atoms to form distorted LiO6 octahedra that share corners with three equivalent Fe(1)O6 octahedra,  an edgeedge with one Li(2)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, edges with two equivalent Cu(1)O6 octahedra, and edges with three equivalent Li(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-19°. Fe(1) is bonded to one O(1), one O(2), one O(4), one O(5), and two equivalent O(3) atoms to form FeO6 octahedra that share  a cornercorner with one Cu(1)O6 octahedra, corners with two equivalent Li(1)O6 octahedra, corners with three equivalent Li(2)O6 octahedra,  an edgeedge with one Fe(1)O6 octahedra,  an edgeedge with one Cu(1)O6 octahedra, edges with two equivalent Li(2)O6 octahedra, and edges with three equivalent Li(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 8-19°. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(5) atoms to form distorted CuO6 octahedra that share corners with two equivalent Fe(1)O6 octahedra, edges with two equivalent Li(1)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, and edges with four equivalent Li(2)O6 octahedra. The corner-sharing octahedral tilt angles are 8°. In the second Cu site, Cu(2) is bonded in a 4-coordinate geometry to one O(2), one O(4), one O(5), and two equivalent O(1) atoms. There are five inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to one Li(1), one Li(2), one Fe(1), one Cu(1), and two equivalent Cu(2) atoms. In the second O site, O(2) is bonded in a 5-coordinate geometry to two equivalent Li(2), one Fe(1), one Cu(1), and one Cu(2) atom. In the third O site, O(3) is bonded to one Li(2), two equivalent Li(1), and two equivalent Fe(1) atoms to form distorted OLi3Fe2 square pyramids that share corners with three equivalent O(5)Li2FeCu2 square pyramids, corners with three equivalent O(4)Li3FeCu square pyramids,  an edgeedge with one O(5)Li2FeCu2 square pyramid, edges with two equivalent O(3)Li3Fe2 square pyramids, and edges with two equivalent O(4)Li3FeCu square pyramids. In the fourth O site, O(4) is bonded to one Li(2), two equivalent Li(1), one Fe(1), and one Cu(2) atom to form distorted OLi3FeCu square pyramids that share corners with three equivalent O(5)Li2FeCu2 square pyramids, corners with three equivalent O(3)Li3Fe2 square pyramids,  an edgeedge with one O(5)Li2FeCu2 square pyramid,  an edgeedge with one O(4)Li3FeCu square pyramid, and edges with two equivalent O(3)Li3Fe2 square pyramids. In the fifth O site, O(5) is bonded to one Li(1), one Li(2), one Fe(1), one Cu(1), and one Cu(2) atom to form distorted OLi2FeCu2 square pyramids that share  a cornercorner with one O(5)Li2FeCu2 square pyramid, corners with three equivalent O(3)Li3Fe2 square pyramids, corners with three equivalent O(4)Li3FeCu square pyramids,  an edgeedge with one O(3)Li3Fe2 square pyramid, and  an edgeedge with one O(4)Li3FeCu square pyramid.
Li4Fe2Cu3O10 crystallizes in the triclinic P-1 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(1), one O(5), two equivalent O(3), and two equivalent O(4) atoms to form distorted LiO6 octahedra that share corners with two equivalent Fe(1)O6 octahedra,  an edgeedge with one Cu(1)O6 octahedra, edges with two equivalent Li(1)O6 octahedra, edges with three equivalent Li(2)O6 octahedra, and edges with three equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-18°. The Li(1)-O(1) bond length is 2.19 Å. The Li(1)-O(5) bond length is 2.20 Å. There is one shorter (1.97 Å) and one longer (2.51 Å) Li(1)-O(3) bond length. There is one shorter (1.99 Å) and one longer (2.22 Å) Li(1)-O(4) bond length. In the second Li site, Li(2) is bonded to one O(1), one O(3), one O(4), one O(5), and two equivalent O(2) atoms to form distorted LiO6 octahedra that share corners with three equivalent Fe(1)O6 octahedra,  an edgeedge with one Li(2)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, edges with two equivalent Cu(1)O6 octahedra, and edges with three equivalent Li(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-19°. The Li(2)-O(1) bond length is 2.16 Å. The Li(2)-O(3) bond length is 2.05 Å. The Li(2)-O(4) bond length is 2.17 Å. The Li(2)-O(5) bond length is 1.98 Å. There is one shorter (2.20 Å) and one longer (2.38 Å) Li(2)-O(2) bond length. Fe(1) is bonded to one O(1), one O(2), one O(4), one O(5), and two equivalent O(3) atoms to form FeO6 octahedra that share  a cornercorner with one Cu(1)O6 octahedra, corners with two equivalent Li(1)O6 octahedra, corners with three equivalent Li(2)O6 octahedra,  an edgeedge with one Fe(1)O6 octahedra,  an edgeedge with one Cu(1)O6 octahedra, edges with two equivalent Li(2)O6 octahedra, and edges with three equivalent Li(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 8-19°. The Fe(1)-O(1) bond length is 2.28 Å. The Fe(1)-O(2) bond length is 1.95 Å. The Fe(1)-O(4) bond length is 1.89 Å. The Fe(1)-O(5) bond length is 1.90 Å. There is one shorter (1.82 Å) and one longer (2.14 Å) Fe(1)-O(3) bond length. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(5) atoms to form distorted CuO6 octahedra that share corners with two equivalent Fe(1)O6 octahedra, edges with two equivalent Li(1)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, and edges with four equivalent Li(2)O6 octahedra. The corner-sharing octahedral tilt angles are 8°. Both Cu(1)-O(1) bond lengths are 2.58 Å. Both Cu(1)-O(2) bond lengths are 1.98 Å. Both Cu(1)-O(5) bond lengths are 1.85 Å. In the second Cu site, Cu(2) is bonded in a 4-coordinate geometry to one O(2), one O(4), one O(5), and two equivalent O(1) atoms. The Cu(2)-O(2) bond length is 1.93 Å. The Cu(2)-O(4) bond length is 1.89 Å. The Cu(2)-O(5) bond length is 2.50 Å. Both Cu(2)-O(1) bond lengths are 1.91 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to one Li(1), one Li(2), one Fe(1), one Cu(1), and two equivalent Cu(2) atoms. In the second O site, O(2) is bonded in a 5-coordinate geometry to two equivalent Li(2), one Fe(1), one Cu(1), and one Cu(2) atom. In the third O site, O(3) is bonded to one Li(2), two equivalent Li(1), and two equivalent Fe(1) atoms to form distorted OLi3Fe2 square pyramids that share corners with three equivalent O(5)Li2FeCu2 square pyramids, corners with three equivalent O(4)Li3FeCu square pyramids,  an edgeedge with one O(5)Li2FeCu2 square pyramid, edges with two equivalent O(3)Li3Fe2 square pyramids, and edges with two equivalent O(4)Li3FeCu square pyramids. In the fourth O site, O(4) is bonded to one Li(2), two equivalent Li(1), one Fe(1), and one Cu(2) atom to form distorted OLi3FeCu square pyramids that share corners with three equivalent O(5)Li2FeCu2 square pyramids, corners with three equivalent O(3)Li3Fe2 square pyramids,  an edgeedge with one O(5)Li2FeCu2 square pyramid,  an edgeedge with one O(4)Li3FeCu square pyramid, and edges with two equivalent O(3)Li3Fe2 square pyramids. In the fifth O site, O(5) is bonded to one Li(1), one Li(2), one Fe(1), one Cu(1), and one Cu(2) atom to form distorted OLi2FeCu2 square pyramids that share  a cornercorner with one O(5)Li2FeCu2 square pyramid, corners with three equivalent O(3)Li3Fe2 square pyramids, corners with three equivalent O(4)Li3FeCu square pyramids,  an edgeedge with one O(3)Li3Fe2 square pyramid, and  an edgeedge with one O(4)Li3FeCu square pyramid.