Tm(FeGe)2 crystallizes in the tetragonal I4/mmm space group. Tm(1) is bonded in a 8-coordinate geometry to eight equivalent Ge(1) atoms. Fe(1) is bonded to four equivalent Ge(1) atoms to form a mixture of distorted corner and edge-sharing FeGe4 tetrahedra. Ge(1) is bonded in a 9-coordinate geometry to four equivalent Tm(1), four equivalent Fe(1), and one Ge(1) atom.
Tm(FeGe)2 crystallizes in the tetragonal I4/mmm space group. Tm(1) is bonded in a 8-coordinate geometry to eight equivalent Ge(1) atoms. All Tm(1)-Ge(1) bond lengths are 3.00 Å. Fe(1) is bonded to four equivalent Ge(1) atoms to form a mixture of distorted corner and edge-sharing FeGe4 tetrahedra. All Fe(1)-Ge(1) bond lengths are 2.44 Å. Ge(1) is bonded in a 9-coordinate geometry to four equivalent Tm(1), four equivalent Fe(1), and one Ge(1) atom. The Ge(1)-Ge(1) bond length is 2.45 Å.