Sm2CoGa8 crystallizes in the tetragonal P4/mmm space group. Sm(1) is bonded to four equivalent Ga(1), four equivalent Ga(2), and four equivalent Ga(3) atoms to form a mixture of face and corner-sharing SmGa12 cuboctahedra. Co(1) is bonded in a body-centered cubic geometry to eight equivalent Ga(1) atoms. There are three inequivalent Ga sites. In the first Ga site, Ga(1) is bonded in a 11-coordinate geometry to two equivalent Sm(1), two equivalent Co(1), two equivalent Ga(3), and five equivalent Ga(1) atoms. In the second Ga site, Ga(2) is bonded in a distorted square co-planar geometry to four equivalent Sm(1) atoms. In the third Ga site, Ga(3) is bonded in a distorted rectangular see-saw-like geometry to four equivalent Sm(1) and four equivalent Ga(1) atoms.
Sm2CoGa8 crystallizes in the tetragonal P4/mmm space group. Sm(1) is bonded to four equivalent Ga(1), four equivalent Ga(2), and four equivalent Ga(3) atoms to form a mixture of face and corner-sharing SmGa12 cuboctahedra. All Sm(1)-Ga(1) bond lengths are 3.03 Å. All Sm(1)-Ga(2) bond lengths are 3.08 Å. All Sm(1)-Ga(3) bond lengths are 3.04 Å. Co(1) is bonded in a body-centered cubic geometry to eight equivalent Ga(1) atoms. All Co(1)-Ga(1) bond lengths are 2.50 Å. There are three inequivalent Ga sites. In the first Ga site, Ga(1) is bonded in a 11-coordinate geometry to two equivalent Sm(1), two equivalent Co(1), two equivalent Ga(3), and five equivalent Ga(1) atoms. Both Ga(1)-Ga(3) bond lengths are 3.00 Å. There is one shorter (2.57 Å) and four longer (3.04 Å) Ga(1)-Ga(1) bond lengths. In the second Ga site, Ga(2) is bonded in a distorted square co-planar geometry to four equivalent Sm(1) atoms. In the third Ga site, Ga(3) is bonded in a distorted rectangular see-saw-like geometry to four equivalent Sm(1) and four equivalent Ga(1) atoms.