Er4NiMg crystallizes in the cubic F-43m space group. Mg(1) is bonded to three equivalent Mg(1), three equivalent Er(1), three equivalent Er(2), and three equivalent Er(3) atoms to form a mixture of corner and face-sharing MgEr9Mg3 cuboctahedra. There are three inequivalent Er sites. In the first Er site, Er(1) is bonded in a 14-coordinate geometry to two equivalent Mg(1), two equivalent Er(2), four equivalent Er(1), four equivalent Er(3), and two equivalent Ni(1) atoms. In the second Er site, Er(2) is bonded in a 3-coordinate geometry to three equivalent Mg(1), three equivalent Er(1), and three equivalent Ni(1) atoms. In the third Er site, Er(3) is bonded in a bent 150 degrees geometry to two equivalent Mg(1), four equivalent Er(1), and two equivalent Ni(1) atoms. Ni(1) is bonded in a 6-coordinate geometry to three equivalent Er(1), three equivalent Er(2), and three equivalent Er(3) atoms.
Er4NiMg crystallizes in the cubic F-43m space group. Mg(1) is bonded to three equivalent Mg(1), three equivalent Er(1), three equivalent Er(2), and three equivalent Er(3) atoms to form a mixture of corner and face-sharing MgEr9Mg3 cuboctahedra. All Mg(1)-Mg(1) bond lengths are 3.00 Å. All Mg(1)-Er(1) bond lengths are 3.25 Å. All Mg(1)-Er(2) bond lengths are 3.44 Å. All Mg(1)-Er(3) bond lengths are 3.47 Å. There are three inequivalent Er sites. In the first Er site, Er(1) is bonded in a 14-coordinate geometry to two equivalent Mg(1), two equivalent Er(2), four equivalent Er(1), four equivalent Er(3), and two equivalent Ni(1) atoms. Both Er(1)-Er(2) bond lengths are 3.44 Å. All Er(1)-Er(1) bond lengths are 3.53 Å. All Er(1)-Er(3) bond lengths are 3.56 Å. Both Er(1)-Ni(1) bond lengths are 3.44 Å. In the second Er site, Er(2) is bonded in a 3-coordinate geometry to three equivalent Mg(1), three equivalent Er(1), and three equivalent Ni(1) atoms. All Er(2)-Ni(1) bond lengths are 2.75 Å. In the third Er site, Er(3) is bonded in a bent 150 degrees geometry to two equivalent Mg(1), four equivalent Er(1), and two equivalent Ni(1) atoms. Both Er(3)-Ni(1) bond lengths are 2.76 Å. Ni(1) is bonded in a 6-coordinate geometry to three equivalent Er(1), three equivalent Er(2), and three equivalent Er(3) atoms.