Li2FeCuO4 is Caswellsilverite-derived structured and crystallizes in the tetragonal I-4m2 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to two O(1,1) and four equivalent O(2) atoms to form LiO6 octahedra that share corners with two equivalent Cu(1)O6 octahedra, corners with four equivalent Li(1)O6 octahedra, edges with four equivalent Li(2)O6 octahedra, edges with four equivalent Fe(1)O6 octahedra, and edges with four equivalent Cu(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-7°. In the second Li site, Li(2) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form LiO6 octahedra that share corners with two equivalent Fe(1)O6 octahedra, corners with four equivalent Li(2)O6 octahedra, edges with four equivalent Li(1)O6 octahedra, edges with four equivalent Fe(1)O6 octahedra, and edges with four equivalent Cu(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-10°. Fe(1) is bonded to two O(2,2) and four equivalent O(1) atoms to form FeO6 octahedra that share corners with two equivalent Li(2)O6 octahedra, corners with four equivalent Fe(1)O6 octahedra, edges with four equivalent Li(1)O6 octahedra, edges with four equivalent Li(2)O6 octahedra, and edges with four equivalent Cu(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-10°. Cu(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form CuO6 octahedra that share corners with two equivalent Li(1)O6 octahedra, corners with four equivalent Cu(1)O6 octahedra, edges with four equivalent Li(1)O6 octahedra, edges with four equivalent Li(2)O6 octahedra, and edges with four equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-7°. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Li(1), two equivalent Li(2), two equivalent Fe(1), and one Cu(1) atom to form OLi3Fe2Cu octahedra that share corners with six equivalent O(1)Li3Fe2Cu octahedra; edges with four equivalent O(1)Li3Fe2Cu octahedra; and edges with eight O(2,2)Li3FeCu2 octahedra. The corner-sharing octahedral tilt angles range from 0-10°. In the second O site, O(2) is bonded to one Li(2), two equivalent Li(1), one Fe(1), and two equivalent Cu(1) atoms to form OLi3FeCu2 octahedra that share corners with six O(2,2)Li3FeCu2 octahedra; edges with four equivalent O(2)Li3FeCu2 octahedra; and edges with eight O(1,1)Li3Fe2Cu octahedra. The corner-sharing octahedral tilt angles range from 0-7°. In the third O site, O(1) is bonded to one Li(1), two equivalent Li(2), two equivalent Fe(1), and one Cu(1) atom to form OLi3Fe2Cu octahedra that share corners with six O(1,1)Li3Fe2Cu octahedra; edges with four equivalent O(1)Li3Fe2Cu octahedra; and edges with eight O(2,2)Li3FeCu2 octahedra. The corner-sharing octahedral tilt angles range from 0-10°. In the fourth O site, O(2) is bonded to one Li(2), two equivalent Li(1), one Fe(1), and two equivalent Cu(1) atoms to form OLi3FeCu2 octahedra that share corners with six O(2,2)Li3FeCu2 octahedra; edges with four equivalent O(2)Li3FeCu2 octahedra; and edges with eight O(1,1)Li3Fe2Cu octahedra. The corner-sharing octahedral tilt angles range from 0-7°.
Li2FeCuO4 is Caswellsilverite-derived structured and crystallizes in the tetragonal I-4m2 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to two O(1,1) and four equivalent O(2) atoms to form LiO6 octahedra that share corners with two equivalent Cu(1)O6 octahedra, corners with four equivalent Li(1)O6 octahedra, edges with four equivalent Li(2)O6 octahedra, edges with four equivalent Fe(1)O6 octahedra, and edges with four equivalent Cu(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-7°. Both Li(1)-O(1,1) bond lengths are 2.29 Å. All Li(1)-O(2) bond lengths are 2.06 Å. In the second Li site, Li(2) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form LiO6 octahedra that share corners with two equivalent Fe(1)O6 octahedra, corners with four equivalent Li(2)O6 octahedra, edges with four equivalent Li(1)O6 octahedra, edges with four equivalent Fe(1)O6 octahedra, and edges with four equivalent Cu(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-10°. Both Li(2)-O(2) bond lengths are 2.23 Å. All Li(2)-O(1) bond lengths are 2.07 Å. Fe(1) is bonded to two O(2,2) and four equivalent O(1) atoms to form FeO6 octahedra that share corners with two equivalent Li(2)O6 octahedra, corners with four equivalent Fe(1)O6 octahedra, edges with four equivalent Li(1)O6 octahedra, edges with four equivalent Li(2)O6 octahedra, and edges with four equivalent Cu(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-10°. Both Fe(1)-O(2,2) bond lengths are 2.00 Å. All Fe(1)-O(1) bond lengths are 2.07 Å. Cu(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form CuO6 octahedra that share corners with two equivalent Li(1)O6 octahedra, corners with four equivalent Cu(1)O6 octahedra, edges with four equivalent Li(1)O6 octahedra, edges with four equivalent Li(2)O6 octahedra, and edges with four equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-7°. Both Cu(1)-O(1) bond lengths are 1.94 Å. All Cu(1)-O(2) bond lengths are 2.06 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Li(1), two equivalent Li(2), two equivalent Fe(1), and one Cu(1) atom to form OLi3Fe2Cu octahedra that share corners with six equivalent O(1)Li3Fe2Cu octahedra; edges with four equivalent O(1)Li3Fe2Cu octahedra; and edges with eight O(2,2)Li3FeCu2 octahedra. The corner-sharing octahedral tilt angles range from 0-10°. In the second O site, O(2) is bonded to one Li(2), two equivalent Li(1), one Fe(1), and two equivalent Cu(1) atoms to form OLi3FeCu2 octahedra that share corners with six O(2,2)Li3FeCu2 octahedra; edges with four equivalent O(2)Li3FeCu2 octahedra; and edges with eight O(1,1)Li3Fe2Cu octahedra. The corner-sharing octahedral tilt angles range from 0-7°. In the third O site, O(1) is bonded to one Li(1), two equivalent Li(2), two equivalent Fe(1), and one Cu(1) atom to form OLi3Fe2Cu octahedra that share corners with six O(1,1)Li3Fe2Cu octahedra; edges with four equivalent O(1)Li3Fe2Cu octahedra; and edges with eight O(2,2)Li3FeCu2 octahedra. The corner-sharing octahedral tilt angles range from 0-10°. Both O(1)-Li(2) bond lengths are 2.07 Å. Both O(1)-Fe(1) bond lengths are 2.07 Å. The O(1)-Cu(1) bond length is 1.94 Å. In the fourth O site, O(2) is bonded to one Li(2), two equivalent Li(1), one Fe(1), and two equivalent Cu(1) atoms to form OLi3FeCu2 octahedra that share corners with six O(2,2)Li3FeCu2 octahedra; edges with four equivalent O(2)Li3FeCu2 octahedra; and edges with eight O(1,1)Li3Fe2Cu octahedra. The corner-sharing octahedral tilt angles range from 0-7°. The O(2)-Li(2) bond length is 2.23 Å. Both O(2)-Li(1) bond lengths are 2.06 Å. Both O(2)-Cu(1) bond lengths are 2.06 Å.