MgTb3 crystallizes in the tetragonal P4/mmm space group. Mg(1) is bonded in a body-centered cubic geometry to eight equivalent Tb(1) atoms. There are two inequivalent Tb sites. In the first Tb site, Tb(1) is bonded in a 4-coordinate geometry to four equivalent Mg(1) and four equivalent Tb(2) atoms. In the second Tb site, Tb(2) is bonded to four equivalent Tb(2) and eight equivalent Tb(1) atoms to form a mixture of face and corner-sharing TbTb12 cuboctahedra.
MgTb3 crystallizes in the tetragonal P4/mmm space group. Mg(1) is bonded in a body-centered cubic geometry to eight equivalent Tb(1) atoms. All Mg(1)-Tb(1) bond lengths are 3.34 Å. There are two inequivalent Tb sites. In the first Tb site, Tb(1) is bonded in a 4-coordinate geometry to four equivalent Mg(1) and four equivalent Tb(2) atoms. All Tb(1)-Tb(2) bond lengths are 3.54 Å. In the second Tb site, Tb(2) is bonded to four equivalent Tb(2) and eight equivalent Tb(1) atoms to form a mixture of face and corner-sharing TbTb12 cuboctahedra. All Tb(2)-Tb(2) bond lengths are 3.62 Å.