Er2NiCu crystallizes in the orthorhombic Amm2 space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded in a 7-coordinate geometry to four equivalent Ni(1) and three equivalent Cu(1) atoms. In the second Er site, Er(2) is bonded in a 7-coordinate geometry to three equivalent Ni(1) and four equivalent Cu(1) atoms. Ni(1) is bonded in a 9-coordinate geometry to three equivalent Er(2), four equivalent Er(1), and two equivalent Cu(1) atoms. Cu(1) is bonded in a 9-coordinate geometry to three equivalent Er(1), four equivalent Er(2), and two equivalent Ni(1) atoms.
Er2NiCu crystallizes in the orthorhombic Amm2 space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded in a 7-coordinate geometry to four equivalent Ni(1) and three equivalent Cu(1) atoms. All Er(1)-Ni(1) bond lengths are 2.91 Å. There are two shorter (2.78 Å) and one longer (2.88 Å) Er(1)-Cu(1) bond length. In the second Er site, Er(2) is bonded in a 7-coordinate geometry to three equivalent Ni(1) and four equivalent Cu(1) atoms. There are two shorter (2.78 Å) and one longer (2.88 Å) Er(2)-Ni(1) bond length. All Er(2)-Cu(1) bond lengths are 2.91 Å. Ni(1) is bonded in a 9-coordinate geometry to three equivalent Er(2), four equivalent Er(1), and two equivalent Cu(1) atoms. Both Ni(1)-Cu(1) bond lengths are 2.61 Å. Cu(1) is bonded in a 9-coordinate geometry to three equivalent Er(1), four equivalent Er(2), and two equivalent Ni(1) atoms.