Ni4CuO5 is Caswellsilverite-like structured and crystallizes in the monoclinic C2/m space group. There are five inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(3), two equivalent O(2), and three equivalent O(1) atoms to form NiO6 octahedra that share corners with three equivalent Ni(2)O6 octahedra, corners with three equivalent Cu(1)O6 octahedra,  an edgeedge with one Cu(1)O6 octahedra, edges with two equivalent Ni(3)O6 octahedra, edges with four equivalent Ni(1)O6 octahedra, and edges with five equivalent Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the second Ni site, Ni(2) is bonded to one O(2), two equivalent O(3), and three equivalent O(1) atoms to form NiO6 octahedra that share corners with three equivalent Ni(1)O6 octahedra, corners with three equivalent Ni(3)O6 octahedra,  an edgeedge with one Ni(3)O6 octahedra, edges with two equivalent Cu(1)O6 octahedra, edges with four equivalent Ni(2)O6 octahedra, and edges with five equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-2°. In the third Ni site, Ni(3) is bonded to one O(2), one O(5), two equivalent O(3), and two equivalent O(4) atoms to form NiO6 octahedra that share corners with three equivalent Ni(2)O6 octahedra, corners with three equivalent Ni(4)O6 octahedra,  an edgeedge with one Ni(2)O6 octahedra,  an edgeedge with one Ni(4)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, edges with two equivalent Ni(3)O6 octahedra, edges with two equivalent Ni(5)O6 octahedra, and edges with four equivalent Cu(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 1-2°. In the fourth Ni site, Ni(4) is bonded to two equivalent O(5) and four equivalent O(4) atoms to form NiO6 octahedra that share corners with six equivalent Ni(3)O6 octahedra, edges with two equivalent Ni(3)O6 octahedra, edges with two equivalent Ni(4)O6 octahedra, edges with four equivalent Ni(5)O6 octahedra, and edges with four equivalent Cu(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 1-2°. In the fifth Ni site, Ni(5) is bonded to two equivalent O(4) and four equivalent O(5) atoms to form NiO6 octahedra that share corners with six equivalent Cu(1)O6 octahedra, edges with two equivalent Ni(5)O6 octahedra, edges with two equivalent Cu(1)O6 octahedra, edges with four equivalent Ni(3)O6 octahedra, and edges with four equivalent Ni(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. Cu(1) is bonded to one O(3), one O(4), two equivalent O(2), and two equivalent O(5) atoms to form CuO6 octahedra that share corners with three equivalent Ni(1)O6 octahedra, corners with three equivalent Ni(5)O6 octahedra,  an edgeedge with one Ni(1)O6 octahedra,  an edgeedge with one Ni(5)O6 octahedra, edges with two equivalent Ni(2)O6 octahedra, edges with two equivalent Ni(4)O6 octahedra, edges with two equivalent Cu(1)O6 octahedra, and edges with four equivalent Ni(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. There are five inequivalent O sites. In the first O site, O(1) is bonded to three equivalent Ni(1) and three equivalent Ni(2) atoms to form ONi6 octahedra that share corners with three equivalent O(2)Cu2Ni4 octahedra, corners with three equivalent O(3)CuNi5 octahedra, edges with three equivalent O(2)Cu2Ni4 octahedra, edges with three equivalent O(3)CuNi5 octahedra, and edges with six equivalent O(1)Ni6 octahedra. The corner-sharing octahedral tilt angles range from 1-2°. In the second O site, O(2) is bonded to one Ni(2), one Ni(3), two equivalent Ni(1), and two equivalent Cu(1) atoms to form OCu2Ni4 octahedra that share corners with three equivalent O(5)Cu2Ni4 octahedra, corners with three equivalent O(1)Ni6 octahedra,  an edgeedge with one O(5)Cu2Ni4 octahedra, edges with two equivalent O(2)Cu2Ni4 octahedra, edges with two equivalent O(4)CuNi5 octahedra, edges with three equivalent O(1)Ni6 octahedra, and edges with four equivalent O(3)CuNi5 octahedra. The corner-sharing octahedral tilt angles range from 0-2°. In the third O site, O(3) is bonded to one Ni(1), two equivalent Ni(2), two equivalent Ni(3), and one Cu(1) atom to form OCuNi5 octahedra that share corners with three equivalent O(4)CuNi5 octahedra, corners with three equivalent O(1)Ni6 octahedra,  an edgeedge with one O(4)CuNi5 octahedra, edges with two equivalent O(5)Cu2Ni4 octahedra, edges with two equivalent O(3)CuNi5 octahedra, edges with three equivalent O(1)Ni6 octahedra, and edges with four equivalent O(2)Cu2Ni4 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the fourth O site, O(4) is bonded to one Ni(5), two equivalent Ni(3), two equivalent Ni(4), and one Cu(1) atom to form OCuNi5 octahedra that share corners with three equivalent O(3)CuNi5 octahedra, corners with three equivalent O(4)CuNi5 octahedra,  an edgeedge with one O(3)CuNi5 octahedra, edges with two equivalent O(2)Cu2Ni4 octahedra, edges with three equivalent O(4)CuNi5 octahedra, and edges with six equivalent O(5)Cu2Ni4 octahedra. The corner-sharing octahedra are not tilted. In the fifth O site, O(5) is bonded to one Ni(3), one Ni(4), two equivalent Ni(5), and two equivalent Cu(1) atoms to form OCu2Ni4 octahedra that share corners with three equivalent O(2)Cu2Ni4 octahedra, corners with three equivalent O(5)Cu2Ni4 octahedra,  an edgeedge with one O(2)Cu2Ni4 octahedra, edges with two equivalent O(3)CuNi5 octahedra, edges with three equivalent O(5)Cu2Ni4 octahedra, and edges with six equivalent O(4)CuNi5 octahedra. The corner-sharing octahedra are not tilted.
Ni4CuO5 is Caswellsilverite-like structured and crystallizes in the monoclinic C2/m space group. There are five inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(3), two equivalent O(2), and three equivalent O(1) atoms to form NiO6 octahedra that share corners with three equivalent Ni(2)O6 octahedra, corners with three equivalent Cu(1)O6 octahedra,  an edgeedge with one Cu(1)O6 octahedra, edges with two equivalent Ni(3)O6 octahedra, edges with four equivalent Ni(1)O6 octahedra, and edges with five equivalent Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. The Ni(1)-O(3) bond length is 2.09 Å. Both Ni(1)-O(2) bond lengths are 2.09 Å. There is one shorter (2.10 Å) and two longer (2.11 Å) Ni(1)-O(1) bond lengths. In the second Ni site, Ni(2) is bonded to one O(2), two equivalent O(3), and three equivalent O(1) atoms to form NiO6 octahedra that share corners with three equivalent Ni(1)O6 octahedra, corners with three equivalent Ni(3)O6 octahedra,  an edgeedge with one Ni(3)O6 octahedra, edges with two equivalent Cu(1)O6 octahedra, edges with four equivalent Ni(2)O6 octahedra, and edges with five equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-2°. The Ni(2)-O(2) bond length is 2.10 Å. Both Ni(2)-O(3) bond lengths are 2.10 Å. All Ni(2)-O(1) bond lengths are 2.11 Å. In the third Ni site, Ni(3) is bonded to one O(2), one O(5), two equivalent O(3), and two equivalent O(4) atoms to form NiO6 octahedra that share corners with three equivalent Ni(2)O6 octahedra, corners with three equivalent Ni(4)O6 octahedra,  an edgeedge with one Ni(2)O6 octahedra,  an edgeedge with one Ni(4)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, edges with two equivalent Ni(3)O6 octahedra, edges with two equivalent Ni(5)O6 octahedra, and edges with four equivalent Cu(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 1-2°. The Ni(3)-O(2) bond length is 2.10 Å. The Ni(3)-O(5) bond length is 2.11 Å. Both Ni(3)-O(3) bond lengths are 2.11 Å. Both Ni(3)-O(4) bond lengths are 2.11 Å. In the fourth Ni site, Ni(4) is bonded to two equivalent O(5) and four equivalent O(4) atoms to form NiO6 octahedra that share corners with six equivalent Ni(3)O6 octahedra, edges with two equivalent Ni(3)O6 octahedra, edges with two equivalent Ni(4)O6 octahedra, edges with four equivalent Ni(5)O6 octahedra, and edges with four equivalent Cu(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 1-2°. Both Ni(4)-O(5) bond lengths are 2.11 Å. All Ni(4)-O(4) bond lengths are 2.11 Å. In the fifth Ni site, Ni(5) is bonded to two equivalent O(4) and four equivalent O(5) atoms to form NiO6 octahedra that share corners with six equivalent Cu(1)O6 octahedra, edges with two equivalent Ni(5)O6 octahedra, edges with two equivalent Cu(1)O6 octahedra, edges with four equivalent Ni(3)O6 octahedra, and edges with four equivalent Ni(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. Both Ni(5)-O(4) bond lengths are 2.08 Å. All Ni(5)-O(5) bond lengths are 2.09 Å. Cu(1) is bonded to one O(3), one O(4), two equivalent O(2), and two equivalent O(5) atoms to form CuO6 octahedra that share corners with three equivalent Ni(1)O6 octahedra, corners with three equivalent Ni(5)O6 octahedra,  an edgeedge with one Ni(1)O6 octahedra,  an edgeedge with one Ni(5)O6 octahedra, edges with two equivalent Ni(2)O6 octahedra, edges with two equivalent Ni(4)O6 octahedra, edges with two equivalent Cu(1)O6 octahedra, and edges with four equivalent Ni(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. The Cu(1)-O(3) bond length is 2.13 Å. The Cu(1)-O(4) bond length is 2.12 Å. Both Cu(1)-O(2) bond lengths are 2.13 Å. Both Cu(1)-O(5) bond lengths are 2.13 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded to three equivalent Ni(1) and three equivalent Ni(2) atoms to form ONi6 octahedra that share corners with three equivalent O(2)Cu2Ni4 octahedra, corners with three equivalent O(3)CuNi5 octahedra, edges with three equivalent O(2)Cu2Ni4 octahedra, edges with three equivalent O(3)CuNi5 octahedra, and edges with six equivalent O(1)Ni6 octahedra. The corner-sharing octahedral tilt angles range from 1-2°. In the second O site, O(2) is bonded to one Ni(2), one Ni(3), two equivalent Ni(1), and two equivalent Cu(1) atoms to form OCu2Ni4 octahedra that share corners with three equivalent O(5)Cu2Ni4 octahedra, corners with three equivalent O(1)Ni6 octahedra,  an edgeedge with one O(5)Cu2Ni4 octahedra, edges with two equivalent O(2)Cu2Ni4 octahedra, edges with two equivalent O(4)CuNi5 octahedra, edges with three equivalent O(1)Ni6 octahedra, and edges with four equivalent O(3)CuNi5 octahedra. The corner-sharing octahedral tilt angles range from 0-2°. In the third O site, O(3) is bonded to one Ni(1), two equivalent Ni(2), two equivalent Ni(3), and one Cu(1) atom to form OCuNi5 octahedra that share corners with three equivalent O(4)CuNi5 octahedra, corners with three equivalent O(1)Ni6 octahedra,  an edgeedge with one O(4)CuNi5 octahedra, edges with two equivalent O(5)Cu2Ni4 octahedra, edges with two equivalent O(3)CuNi5 octahedra, edges with three equivalent O(1)Ni6 octahedra, and edges with four equivalent O(2)Cu2Ni4 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the fourth O site, O(4) is bonded to one Ni(5), two equivalent Ni(3), two equivalent Ni(4), and one Cu(1) atom to form OCuNi5 octahedra that share corners with three equivalent O(3)CuNi5 octahedra, corners with three equivalent O(4)CuNi5 octahedra,  an edgeedge with one O(3)CuNi5 octahedra, edges with two equivalent O(2)Cu2Ni4 octahedra, edges with three equivalent O(4)CuNi5 octahedra, and edges with six equivalent O(5)Cu2Ni4 octahedra. The corner-sharing octahedra are not tilted. In the fifth O site, O(5) is bonded to one Ni(3), one Ni(4), two equivalent Ni(5), and two equivalent Cu(1) atoms to form OCu2Ni4 octahedra that share corners with three equivalent O(2)Cu2Ni4 octahedra, corners with three equivalent O(5)Cu2Ni4 octahedra,  an edgeedge with one O(2)Cu2Ni4 octahedra, edges with two equivalent O(3)CuNi5 octahedra, edges with three equivalent O(5)Cu2Ni4 octahedra, and edges with six equivalent O(4)CuNi5 octahedra. The corner-sharing octahedra are not tilted.