TmNiGe2 crystallizes in the orthorhombic Cmcm space group. Tm(1) is bonded in a 14-coordinate geometry to four equivalent Ni(1), four equivalent Ge(2), and six equivalent Ge(1) atoms. Ni(1) is bonded in a 9-coordinate geometry to four equivalent Tm(1), one Ge(1), and four equivalent Ge(2) atoms. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded in a 9-coordinate geometry to six equivalent Tm(1), one Ni(1), and two equivalent Ge(1) atoms. In the second Ge site, Ge(2) is bonded in a 8-coordinate geometry to four equivalent Tm(1) and four equivalent Ni(1) atoms.
TmNiGe2 crystallizes in the orthorhombic Cmcm space group. Tm(1) is bonded in a 14-coordinate geometry to four equivalent Ni(1), four equivalent Ge(2), and six equivalent Ge(1) atoms. All Tm(1)-Ni(1) bond lengths are 3.12 Å. There are two shorter (3.07 Å) and two longer (3.19 Å) Tm(1)-Ge(2) bond lengths. There are four shorter (3.11 Å) and two longer (3.19 Å) Tm(1)-Ge(1) bond lengths. Ni(1) is bonded in a 9-coordinate geometry to four equivalent Tm(1), one Ge(1), and four equivalent Ge(2) atoms. The Ni(1)-Ge(1) bond length is 2.28 Å. There are two shorter (2.38 Å) and two longer (2.39 Å) Ni(1)-Ge(2) bond lengths. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded in a 9-coordinate geometry to six equivalent Tm(1), one Ni(1), and two equivalent Ge(1) atoms. Both Ge(1)-Ge(1) bond lengths are 2.48 Å. In the second Ge site, Ge(2) is bonded in a 8-coordinate geometry to four equivalent Tm(1) and four equivalent Ni(1) atoms.