TmNi4Al crystallizes in the orthorhombic Cmmm space group. Tm(1) is bonded in a 18-coordinate geometry to six equivalent Ni(1), eight equivalent Ni(2), and four equivalent Al(1) atoms. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a 9-coordinate geometry to three equivalent Tm(1), four equivalent Ni(2), and two equivalent Al(1) atoms. In the second Ni site, Ni(2) is bonded to four equivalent Tm(1), two equivalent Ni(2), four equivalent Ni(1), and two equivalent Al(1) atoms to form a mixture of distorted corner, edge, and face-sharing NiTm4Al2Ni6 cuboctahedra. Al(1) is bonded in a 8-coordinate geometry to four equivalent Tm(1), four equivalent Ni(1), and four equivalent Ni(2) atoms.
TmNi4Al crystallizes in the orthorhombic Cmmm space group. Tm(1) is bonded in a 18-coordinate geometry to six equivalent Ni(1), eight equivalent Ni(2), and four equivalent Al(1) atoms. There are two shorter (2.75 Å) and four longer (2.83 Å) Tm(1)-Ni(1) bond lengths. All Tm(1)-Ni(2) bond lengths are 3.12 Å. All Tm(1)-Al(1) bond lengths are 3.17 Å. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a 9-coordinate geometry to three equivalent Tm(1), four equivalent Ni(2), and two equivalent Al(1) atoms. All Ni(1)-Ni(2) bond lengths are 2.43 Å. Both Ni(1)-Al(1) bond lengths are 2.43 Å. In the second Ni site, Ni(2) is bonded to four equivalent Tm(1), two equivalent Ni(2), four equivalent Ni(1), and two equivalent Al(1) atoms to form a mixture of distorted corner, edge, and face-sharing NiTm4Al2Ni6 cuboctahedra. Both Ni(2)-Ni(2) bond lengths are 2.46 Å. Both Ni(2)-Al(1) bond lengths are 2.41 Å. Al(1) is bonded in a 8-coordinate geometry to four equivalent Tm(1), four equivalent Ni(1), and four equivalent Ni(2) atoms.