Th2CoSi3 is hexagonal omega structure-derived structured and crystallizes in the orthorhombic Imm2 space group. There are two inequivalent Th sites. In the first Th site, Th(1) is bonded to four equivalent Co(1), two equivalent Si(1), two equivalent Si(3), and four equivalent Si(2) atoms to form ThCo4Si8 cuboctahedra that share edges with four equivalent Th(1)Co4Si8 cuboctahedra, edges with eight equivalent Th(2)Co2Si10 cuboctahedra, faces with four equivalent Th(2)Co2Si10 cuboctahedra, and faces with four equivalent Th(1)Co4Si8 cuboctahedra. In the second Th site, Th(2) is bonded to two equivalent Co(1), two equivalent Si(2), four equivalent Si(1), and four equivalent Si(3) atoms to form ThCo2Si10 cuboctahedra that share edges with four equivalent Th(2)Co2Si10 cuboctahedra, edges with eight equivalent Th(1)Co4Si8 cuboctahedra, faces with four equivalent Th(2)Co2Si10 cuboctahedra, and faces with four equivalent Th(1)Co4Si8 cuboctahedra. Co(1) is bonded in a 9-coordinate geometry to two equivalent Th(2), four equivalent Th(1), one Si(2), and two equivalent Si(1) atoms. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to two equivalent Th(1), four equivalent Th(2), two equivalent Co(1), and one Si(3) atom. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to two equivalent Th(2), four equivalent Th(1), one Co(1), and two equivalent Si(3) atoms. In the third Si site, Si(3) is bonded in a 9-coordinate geometry to two equivalent Th(1), four equivalent Th(2), one Si(1), and two equivalent Si(2) atoms.
Th2CoSi3 is hexagonal omega structure-derived structured and crystallizes in the orthorhombic Imm2 space group. There are two inequivalent Th sites. In the first Th site, Th(1) is bonded to four equivalent Co(1), two equivalent Si(1), two equivalent Si(3), and four equivalent Si(2) atoms to form ThCo4Si8 cuboctahedra that share edges with four equivalent Th(1)Co4Si8 cuboctahedra, edges with eight equivalent Th(2)Co2Si10 cuboctahedra, faces with four equivalent Th(2)Co2Si10 cuboctahedra, and faces with four equivalent Th(1)Co4Si8 cuboctahedra. All Th(1)-Co(1) bond lengths are 3.15 Å. Both Th(1)-Si(1) bond lengths are 3.04 Å. Both Th(1)-Si(3) bond lengths are 3.11 Å. All Th(1)-Si(2) bond lengths are 3.10 Å. In the second Th site, Th(2) is bonded to two equivalent Co(1), two equivalent Si(2), four equivalent Si(1), and four equivalent Si(3) atoms to form ThCo2Si10 cuboctahedra that share edges with four equivalent Th(2)Co2Si10 cuboctahedra, edges with eight equivalent Th(1)Co4Si8 cuboctahedra, faces with four equivalent Th(2)Co2Si10 cuboctahedra, and faces with four equivalent Th(1)Co4Si8 cuboctahedra. Both Th(2)-Co(1) bond lengths are 3.01 Å. Both Th(2)-Si(2) bond lengths are 3.25 Å. All Th(2)-Si(1) bond lengths are 3.14 Å. All Th(2)-Si(3) bond lengths are 3.16 Å. Co(1) is bonded in a 9-coordinate geometry to two equivalent Th(2), four equivalent Th(1), one Si(2), and two equivalent Si(1) atoms. The Co(1)-Si(2) bond length is 2.25 Å. Both Co(1)-Si(1) bond lengths are 2.32 Å. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to two equivalent Th(1), four equivalent Th(2), two equivalent Co(1), and one Si(3) atom. The Si(1)-Si(3) bond length is 2.40 Å. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to two equivalent Th(2), four equivalent Th(1), one Co(1), and two equivalent Si(3) atoms. Both Si(2)-Si(3) bond lengths are 2.42 Å. In the third Si site, Si(3) is bonded in a 9-coordinate geometry to two equivalent Th(1), four equivalent Th(2), one Si(1), and two equivalent Si(2) atoms.