Li4Fe3CuO8 is alpha Po-derived structured and crystallizes in the trigonal R-3m space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form LiO6 octahedra that share corners with six equivalent Fe(1)O6 octahedra, edges with two equivalent Li(2)O6 octahedra, edges with two equivalent Cu(1)O6 octahedra, edges with four equivalent Li(1)O6 octahedra, and edges with four equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles are 4°. In the second Li site, Li(2) is bonded to six equivalent O(2) atoms to form LiO6 octahedra that share corners with six equivalent Cu(1)O6 octahedra, edges with six equivalent Li(1)O6 octahedra, and edges with six equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles are 4°. Fe(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form FeO6 octahedra that share corners with six equivalent Li(1)O6 octahedra, edges with two equivalent Li(2)O6 octahedra, edges with two equivalent Cu(1)O6 octahedra, edges with four equivalent Li(1)O6 octahedra, and edges with four equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles are 4°. Cu(1) is bonded to six equivalent O(2) atoms to form CuO6 octahedra that share corners with six equivalent Li(2)O6 octahedra, edges with six equivalent Li(1)O6 octahedra, and edges with six equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles are 4°. There are two inequivalent O sites. In the first O site, O(1) is bonded to three equivalent Li(1) and three equivalent Fe(1) atoms to form OLi3Fe3 octahedra that share corners with six equivalent O(1)Li3Fe3 octahedra and edges with twelve equivalent O(2)Li3Fe2Cu octahedra. The corner-sharing octahedra are not tilted. In the second O site, O(2) is bonded to one Li(2), two equivalent Li(1), two equivalent Fe(1), and one Cu(1) atom to form OLi3Fe2Cu octahedra that share corners with six equivalent O(2)Li3Fe2Cu octahedra, edges with four equivalent O(1)Li3Fe3 octahedra, and edges with eight equivalent O(2)Li3Fe2Cu octahedra. The corner-sharing octahedra are not tilted.
Li4Fe3CuO8 is alpha Po-derived structured and crystallizes in the trigonal R-3m space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form LiO6 octahedra that share corners with six equivalent Fe(1)O6 octahedra, edges with two equivalent Li(2)O6 octahedra, edges with two equivalent Cu(1)O6 octahedra, edges with four equivalent Li(1)O6 octahedra, and edges with four equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles are 4°. Both Li(1)-O(1) bond lengths are 2.16 Å. All Li(1)-O(2) bond lengths are 2.16 Å. In the second Li site, Li(2) is bonded to six equivalent O(2) atoms to form LiO6 octahedra that share corners with six equivalent Cu(1)O6 octahedra, edges with six equivalent Li(1)O6 octahedra, and edges with six equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles are 4°. All Li(2)-O(2) bond lengths are 2.16 Å. Fe(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form FeO6 octahedra that share corners with six equivalent Li(1)O6 octahedra, edges with two equivalent Li(2)O6 octahedra, edges with two equivalent Cu(1)O6 octahedra, edges with four equivalent Li(1)O6 octahedra, and edges with four equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles are 4°. Both Fe(1)-O(1) bond lengths are 2.05 Å. All Fe(1)-O(2) bond lengths are 2.05 Å. Cu(1) is bonded to six equivalent O(2) atoms to form CuO6 octahedra that share corners with six equivalent Li(2)O6 octahedra, edges with six equivalent Li(1)O6 octahedra, and edges with six equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles are 4°. All Cu(1)-O(2) bond lengths are 2.05 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded to three equivalent Li(1) and three equivalent Fe(1) atoms to form OLi3Fe3 octahedra that share corners with six equivalent O(1)Li3Fe3 octahedra and edges with twelve equivalent O(2)Li3Fe2Cu octahedra. The corner-sharing octahedra are not tilted. In the second O site, O(2) is bonded to one Li(2), two equivalent Li(1), two equivalent Fe(1), and one Cu(1) atom to form OLi3Fe2Cu octahedra that share corners with six equivalent O(2)Li3Fe2Cu octahedra, edges with four equivalent O(1)Li3Fe3 octahedra, and edges with eight equivalent O(2)Li3Fe2Cu octahedra. The corner-sharing octahedra are not tilted.