MgTm4Ge4 crystallizes in the orthorhombic Pnma space group. Mg(1) is bonded to one Ge(2), two equivalent Ge(1), and two equivalent Ge(3) atoms to form distorted corner-sharing MgGe5 square pyramids. There are two inequivalent Tm sites. In the first Tm site, Tm(1) is bonded in a 7-coordinate geometry to one Ge(2), two equivalent Ge(3), and four equivalent Ge(1) atoms. In the second Tm site, Tm(2) is bonded in a 6-coordinate geometry to one Ge(3), two equivalent Ge(2), and three equivalent Ge(1) atoms. There are three inequivalent Ge sites. In the first Ge site, Ge(3) is bonded in a 9-coordinate geometry to two equivalent Mg(1), two equivalent Tm(2), four equivalent Tm(1), and one Ge(2) atom. In the second Ge site, Ge(1) is bonded in a 9-coordinate geometry to one Mg(1), three equivalent Tm(2), four equivalent Tm(1), and one Ge(1) atom. In the third Ge site, Ge(2) is bonded in a 8-coordinate geometry to one Mg(1), two equivalent Tm(1), four equivalent Tm(2), and one Ge(3) atom.
MgTm4Ge4 crystallizes in the orthorhombic Pnma space group. Mg(1) is bonded to one Ge(2), two equivalent Ge(1), and two equivalent Ge(3) atoms to form distorted corner-sharing MgGe5 square pyramids. The Mg(1)-Ge(2) bond length is 2.73 Å. Both Mg(1)-Ge(1) bond lengths are 3.10 Å. There is one shorter (2.81 Å) and one longer (2.82 Å) Mg(1)-Ge(3) bond length. There are two inequivalent Tm sites. In the first Tm site, Tm(1) is bonded in a 7-coordinate geometry to one Ge(2), two equivalent Ge(3), and four equivalent Ge(1) atoms. The Tm(1)-Ge(2) bond length is 3.09 Å. There is one shorter (3.00 Å) and one longer (3.11 Å) Tm(1)-Ge(3) bond length. There are a spread of Tm(1)-Ge(1) bond distances ranging from 2.94-3.25 Å. In the second Tm site, Tm(2) is bonded in a 6-coordinate geometry to one Ge(3), two equivalent Ge(2), and three equivalent Ge(1) atoms. The Tm(2)-Ge(3) bond length is 3.02 Å. There is one shorter (2.87 Å) and one longer (2.89 Å) Tm(2)-Ge(2) bond length. There are a spread of Tm(2)-Ge(1) bond distances ranging from 2.81-2.97 Å. There are three inequivalent Ge sites. In the first Ge site, Ge(3) is bonded in a 9-coordinate geometry to two equivalent Mg(1), two equivalent Tm(2), four equivalent Tm(1), and one Ge(2) atom. The Ge(3)-Ge(2) bond length is 2.59 Å. In the second Ge site, Ge(1) is bonded in a 9-coordinate geometry to one Mg(1), three equivalent Tm(2), four equivalent Tm(1), and one Ge(1) atom. The Ge(1)-Ge(1) bond length is 2.74 Å. In the third Ge site, Ge(2) is bonded in a 8-coordinate geometry to one Mg(1), two equivalent Tm(1), four equivalent Tm(2), and one Ge(3) atom.