Sm(Mn2Ni)4 crystallizes in the tetragonal I4/mmm space group. Sm(1) is bonded in a 20-coordinate geometry to eight equivalent Mn(1), eight equivalent Mn(2), and four equivalent Ni(1) atoms. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to two equivalent Sm(1), two equivalent Mn(1), four equivalent Mn(2), and four equivalent Ni(1) atoms to form a mixture of distorted edge, corner, and face-sharing MnSm2Mn6Ni4 cuboctahedra. In the second Mn site, Mn(2) is bonded in a 12-coordinate geometry to two equivalent Sm(1), two equivalent Mn(2), four equivalent Mn(1), and four equivalent Ni(1) atoms. Ni(1) is bonded in a 10-coordinate geometry to one Sm(1), four equivalent Mn(1), four equivalent Mn(2), and one Ni(1) atom.
Sm(Mn2Ni)4 crystallizes in the tetragonal I4/mmm space group. Sm(1) is bonded in a 20-coordinate geometry to eight equivalent Mn(1), eight equivalent Mn(2), and four equivalent Ni(1) atoms. All Sm(1)-Mn(1) bond lengths are 3.23 Å. All Sm(1)-Mn(2) bond lengths are 3.15 Å. All Sm(1)-Ni(1) bond lengths are 2.95 Å. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to two equivalent Sm(1), two equivalent Mn(1), four equivalent Mn(2), and four equivalent Ni(1) atoms to form a mixture of distorted edge, corner, and face-sharing MnSm2Mn6Ni4 cuboctahedra. Both Mn(1)-Mn(1) bond lengths are 2.42 Å. All Mn(1)-Mn(2) bond lengths are 2.44 Å. All Mn(1)-Ni(1) bond lengths are 2.58 Å. In the second Mn site, Mn(2) is bonded in a 12-coordinate geometry to two equivalent Sm(1), two equivalent Mn(2), four equivalent Mn(1), and four equivalent Ni(1) atoms. Both Mn(2)-Mn(2) bond lengths are 2.86 Å. There are two shorter (2.55 Å) and two longer (2.59 Å) Mn(2)-Ni(1) bond lengths. Ni(1) is bonded in a 10-coordinate geometry to one Sm(1), four equivalent Mn(1), four equivalent Mn(2), and one Ni(1) atom. The Ni(1)-Ni(1) bond length is 2.55 Å.