MgTm2Se4 crystallizes in the tetragonal I-42d space group. Mg(1) is bonded in a 4-coordinate geometry to eight equivalent Se(1) atoms. Tm(1) is bonded in a 8-coordinate geometry to eight equivalent Se(1) atoms. Se(1) is bonded in a 6-coordinate geometry to two equivalent Mg(1) and four equivalent Tm(1) atoms.
MgTm2Se4 crystallizes in the tetragonal I-42d space group. Mg(1) is bonded in a 4-coordinate geometry to eight equivalent Se(1) atoms. There are four shorter (2.72 Å) and four longer (3.28 Å) Mg(1)-Se(1) bond lengths. Tm(1) is bonded in a 8-coordinate geometry to eight equivalent Se(1) atoms. There are a spread of Tm(1)-Se(1) bond distances ranging from 2.79-3.25 Å. Se(1) is bonded in a 6-coordinate geometry to two equivalent Mg(1) and four equivalent Tm(1) atoms.