ErNi4 crystallizes in the monoclinic C2/m space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded in a 18-coordinate geometry to four equivalent Ni(2), six equivalent Ni(1), and eight equivalent Ni(3) atoms. In the second Er site, Er(2) is bonded in a 14-coordinate geometry to two equivalent Ni(2), four equivalent Ni(3), and eight equivalent Ni(4) atoms. There are four inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a 12-coordinate geometry to three equivalent Er(1), two equivalent Ni(2), three equivalent Ni(1), and four equivalent Ni(3) atoms. In the second Ni site, Ni(2) is bonded to two equivalent Er(1), two equivalent Er(2), two equivalent Ni(1), two equivalent Ni(4), and four equivalent Ni(3) atoms to form a mixture of face, corner, and edge-sharing NiEr4Ni8 cuboctahedra. In the third Ni site, Ni(3) is bonded to two equivalent Er(1), two equivalent Er(2), two equivalent Ni(1), two equivalent Ni(2), two equivalent Ni(3), and two equivalent Ni(4) atoms to form a mixture of face, corner, and edge-sharing NiEr4Ni8 cuboctahedra. In the fourth Ni site, Ni(4) is bonded in a 12-coordinate geometry to four equivalent Er(2), one Ni(2), two equivalent Ni(3), and five equivalent Ni(4) atoms.
ErNi4 crystallizes in the monoclinic C2/m space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded in a 18-coordinate geometry to four equivalent Ni(2), six equivalent Ni(1), and eight equivalent Ni(3) atoms. There are two shorter (3.10 Å) and two longer (3.17 Å) Er(1)-Ni(2) bond lengths. There are four shorter (2.79 Å) and two longer (2.81 Å) Er(1)-Ni(1) bond lengths. All Er(1)-Ni(3) bond lengths are 3.13 Å. In the second Er site, Er(2) is bonded in a 14-coordinate geometry to two equivalent Ni(2), four equivalent Ni(3), and eight equivalent Ni(4) atoms. Both Er(2)-Ni(2) bond lengths are 2.87 Å. There are two shorter (2.87 Å) and two longer (2.91 Å) Er(2)-Ni(3) bond lengths. There are a spread of Er(2)-Ni(4) bond distances ranging from 2.80-2.90 Å. There are four inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a 12-coordinate geometry to three equivalent Er(1), two equivalent Ni(2), three equivalent Ni(1), and four equivalent Ni(3) atoms. Both Ni(1)-Ni(2) bond lengths are 2.44 Å. There are two shorter (2.79 Å) and one longer (2.80 Å) Ni(1)-Ni(1) bond length. There are two shorter (2.42 Å) and two longer (2.43 Å) Ni(1)-Ni(3) bond lengths. In the second Ni site, Ni(2) is bonded to two equivalent Er(1), two equivalent Er(2), two equivalent Ni(1), two equivalent Ni(4), and four equivalent Ni(3) atoms to form a mixture of face, corner, and edge-sharing NiEr4Ni8 cuboctahedra. Both Ni(2)-Ni(4) bond lengths are 2.51 Å. There are two shorter (2.42 Å) and two longer (2.43 Å) Ni(2)-Ni(3) bond lengths. In the third Ni site, Ni(3) is bonded to two equivalent Er(1), two equivalent Er(2), two equivalent Ni(1), two equivalent Ni(2), two equivalent Ni(3), and two equivalent Ni(4) atoms to form a mixture of face, corner, and edge-sharing NiEr4Ni8 cuboctahedra. Both Ni(3)-Ni(3) bond lengths are 2.41 Å. There is one shorter (2.47 Å) and one longer (2.49 Å) Ni(3)-Ni(4) bond length. In the fourth Ni site, Ni(4) is bonded in a 12-coordinate geometry to four equivalent Er(2), one Ni(2), two equivalent Ni(3), and five equivalent Ni(4) atoms. There are a spread of Ni(4)-Ni(4) bond distances ranging from 2.43-2.90 Å.