Sc4Ir7Si6 crystallizes in the cubic Im-3m space group. Sc(1) is bonded to six equivalent Ir(1) and six equivalent Si(1) atoms to form ScSi6Ir6 cuboctahedra that share corners with twelve equivalent Sc(1)Si6Ir6 cuboctahedra, faces with six equivalent Sc(1)Si6Ir6 cuboctahedra, and faces with two equivalent Ir(2)Si6 octahedra. There are two inequivalent Ir sites. In the first Ir site, Ir(2) is bonded to six equivalent Si(1) atoms to form IrSi6 octahedra that share faces with eight equivalent Sc(1)Si6Ir6 cuboctahedra. In the second Ir site, Ir(1) is bonded in a 8-coordinate geometry to four equivalent Sc(1) and four equivalent Si(1) atoms. Si(1) is bonded in a 9-coordinate geometry to four equivalent Sc(1), one Ir(2), and four equivalent Ir(1) atoms.
Sc4Ir7Si6 crystallizes in the cubic Im-3m space group. Sc(1) is bonded to six equivalent Ir(1) and six equivalent Si(1) atoms to form ScSi6Ir6 cuboctahedra that share corners with twelve equivalent Sc(1)Si6Ir6 cuboctahedra, faces with six equivalent Sc(1)Si6Ir6 cuboctahedra, and faces with two equivalent Ir(2)Si6 octahedra. All Sc(1)-Ir(1) bond lengths are 2.84 Å. All Sc(1)-Si(1) bond lengths are 2.89 Å. There are two inequivalent Ir sites. In the first Ir site, Ir(2) is bonded to six equivalent Si(1) atoms to form IrSi6 octahedra that share faces with eight equivalent Sc(1)Si6Ir6 cuboctahedra. All Ir(2)-Si(1) bond lengths are 2.56 Å. In the second Ir site, Ir(1) is bonded in a 8-coordinate geometry to four equivalent Sc(1) and four equivalent Si(1) atoms. All Ir(1)-Si(1) bond lengths are 2.48 Å. Si(1) is bonded in a 9-coordinate geometry to four equivalent Sc(1), one Ir(2), and four equivalent Ir(1) atoms.