La(IrSi)2 crystallizes in the tetragonal P4/nmm space group. La(1) is bonded in a 16-coordinate geometry to four equivalent Ir(1), four equivalent Ir(2), four equivalent Si(1), and four equivalent Si(2) atoms. There are two inequivalent Ir sites. In the first Ir site, Ir(1) is bonded in a 9-coordinate geometry to four equivalent La(1), one Si(1), and four equivalent Si(2) atoms. In the second Ir site, Ir(2) is bonded in a 4-coordinate geometry to four equivalent La(1) and four equivalent Si(1) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 5-coordinate geometry to four equivalent La(1), one Ir(1), and four equivalent Ir(2) atoms. In the second Si site, Si(2) is bonded in a 4-coordinate geometry to four equivalent La(1) and four equivalent Ir(1) atoms.
La(IrSi)2 crystallizes in the tetragonal P4/nmm space group. La(1) is bonded in a 16-coordinate geometry to four equivalent Ir(1), four equivalent Ir(2), four equivalent Si(1), and four equivalent Si(2) atoms. All La(1)-Ir(1) bond lengths are 3.20 Å. All La(1)-Ir(2) bond lengths are 3.31 Å. All La(1)-Si(1) bond lengths are 3.24 Å. All La(1)-Si(2) bond lengths are 3.21 Å. There are two inequivalent Ir sites. In the first Ir site, Ir(1) is bonded in a 9-coordinate geometry to four equivalent La(1), one Si(1), and four equivalent Si(2) atoms. The Ir(1)-Si(1) bond length is 2.45 Å. All Ir(1)-Si(2) bond lengths are 2.45 Å. In the second Ir site, Ir(2) is bonded in a 4-coordinate geometry to four equivalent La(1) and four equivalent Si(1) atoms. All Ir(2)-Si(1) bond lengths are 2.46 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 5-coordinate geometry to four equivalent La(1), one Ir(1), and four equivalent Ir(2) atoms. In the second Si site, Si(2) is bonded in a 4-coordinate geometry to four equivalent La(1) and four equivalent Ir(1) atoms.