LaCoSi2 crystallizes in the orthorhombic Cmcm space group. La(1) is bonded in a 14-coordinate geometry to four equivalent Co(1), four equivalent Si(2), and six equivalent Si(1) atoms. Co(1) is bonded in a 9-coordinate geometry to four equivalent La(1), one Si(1), and four equivalent Si(2) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to six equivalent La(1), one Co(1), and two equivalent Si(1) atoms. In the second Si site, Si(2) is bonded in a 8-coordinate geometry to four equivalent La(1) and four equivalent Co(1) atoms.
LaCoSi2 crystallizes in the orthorhombic Cmcm space group. La(1) is bonded in a 14-coordinate geometry to four equivalent Co(1), four equivalent Si(2), and six equivalent Si(1) atoms. All La(1)-Co(1) bond lengths are 3.18 Å. There are two shorter (3.11 Å) and two longer (3.15 Å) La(1)-Si(2) bond lengths. There are four shorter (3.13 Å) and two longer (3.29 Å) La(1)-Si(1) bond lengths. Co(1) is bonded in a 9-coordinate geometry to four equivalent La(1), one Si(1), and four equivalent Si(2) atoms. The Co(1)-Si(1) bond length is 2.28 Å. There are two shorter (2.33 Å) and two longer (2.40 Å) Co(1)-Si(2) bond lengths. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to six equivalent La(1), one Co(1), and two equivalent Si(1) atoms. Both Si(1)-Si(1) bond lengths are 2.50 Å. In the second Si site, Si(2) is bonded in a 8-coordinate geometry to four equivalent La(1) and four equivalent Co(1) atoms.