Tm3NiGa5 crystallizes in the hexagonal P-62m space group. Tm(1) is bonded in a 11-coordinate geometry to one Ni(1), four equivalent Ga(2), and six equivalent Ga(1) atoms. Ni(1) is bonded in a 9-coordinate geometry to three equivalent Tm(1) and six equivalent Ga(1) atoms. There are two inequivalent Ga sites. In the first Ga site, Ga(1) is bonded to six equivalent Tm(1), two equivalent Ni(1), two equivalent Ga(1), and two equivalent Ga(2) atoms to form a mixture of distorted edge, face, and corner-sharing GaTm6Ga4Ni2 cuboctahedra. In the second Ga site, Ga(2) is bonded in a 9-coordinate geometry to six equivalent Tm(1) and three equivalent Ga(1) atoms.
Tm3NiGa5 crystallizes in the hexagonal P-62m space group. Tm(1) is bonded in a 11-coordinate geometry to one Ni(1), four equivalent Ga(2), and six equivalent Ga(1) atoms. The Tm(1)-Ni(1) bond length is 2.74 Å. All Tm(1)-Ga(2) bond lengths are 2.92 Å. There are four shorter (3.16 Å) and two longer (3.20 Å) Tm(1)-Ga(1) bond lengths. Ni(1) is bonded in a 9-coordinate geometry to three equivalent Tm(1) and six equivalent Ga(1) atoms. All Ni(1)-Ga(1) bond lengths are 2.62 Å. There are two inequivalent Ga sites. In the first Ga site, Ga(1) is bonded to six equivalent Tm(1), two equivalent Ni(1), two equivalent Ga(1), and two equivalent Ga(2) atoms to form a mixture of distorted edge, face, and corner-sharing GaTm6Ga4Ni2 cuboctahedra. Both Ga(1)-Ga(1) bond lengths are 2.75 Å. Both Ga(1)-Ga(2) bond lengths are 2.65 Å. In the second Ga site, Ga(2) is bonded in a 9-coordinate geometry to six equivalent Tm(1) and three equivalent Ga(1) atoms.