SmCoSi3 crystallizes in the tetragonal I4mm space group. Sm(1) is bonded in a 17-coordinate geometry to five equivalent Co(1), four equivalent Si(2), and eight equivalent Si(1) atoms. Co(1) is bonded in a 5-coordinate geometry to five equivalent Sm(1), one Si(2), and four equivalent Si(1) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 8-coordinate geometry to four equivalent Sm(1), two equivalent Co(1), and two equivalent Si(2) atoms. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to four equivalent Sm(1), one Co(1), and four equivalent Si(1) atoms.
SmCoSi3 crystallizes in the tetragonal I4mm space group. Sm(1) is bonded in a 17-coordinate geometry to five equivalent Co(1), four equivalent Si(2), and eight equivalent Si(1) atoms. There are four shorter (3.25 Å) and one longer (3.27 Å) Sm(1)-Co(1) bond length. All Sm(1)-Si(2) bond lengths are 2.98 Å. There are four shorter (3.09 Å) and four longer (3.19 Å) Sm(1)-Si(1) bond lengths. Co(1) is bonded in a 5-coordinate geometry to five equivalent Sm(1), one Si(2), and four equivalent Si(1) atoms. The Co(1)-Si(2) bond length is 2.23 Å. All Co(1)-Si(1) bond lengths are 2.25 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 8-coordinate geometry to four equivalent Sm(1), two equivalent Co(1), and two equivalent Si(2) atoms. Both Si(1)-Si(2) bond lengths are 2.59 Å. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to four equivalent Sm(1), one Co(1), and four equivalent Si(1) atoms.