UIr2Si2 crystallizes in the tetragonal P4/nmm space group. U(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 5-coordinate geometry to four equivalent U(1), one Si(1), and four equivalent Si(2) atoms. In the second Ir site, Ir(2) is bonded to four equivalent U(1) and four equivalent Si(1) atoms to form distorted IrU4Si4 tetrahedra that share corners with twelve equivalent Si(2)U4Ir4 tetrahedra, edges with two equivalent Si(2)U4Ir4 tetrahedra, edges with four equivalent Ir(2)U4Si4 tetrahedra, and faces with four equivalent Ir(2)U4Si4 tetrahedra. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 5-coordinate geometry to four equivalent U(1), one Ir(1), and four equivalent Ir(2) atoms. In the second Si site, Si(2) is bonded to four equivalent U(1) and four equivalent Ir(1) atoms to form distorted SiU4Ir4 tetrahedra that share corners with twelve equivalent Ir(2)U4Si4 tetrahedra, edges with two equivalent Ir(2)U4Si4 tetrahedra, edges with four equivalent Si(2)U4Ir4 tetrahedra, and faces with four equivalent Si(2)U4Ir4 tetrahedra.
UIr2Si2 crystallizes in the tetragonal P4/nmm space group. U(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 U(1)-Ir(1) bond lengths are 3.14 Å. All U(1)-Ir(2) bond lengths are 3.25 Å. All U(1)-Si(1) bond lengths are 3.17 Å. All U(1)-Si(2) bond lengths are 3.16 Å. There are two inequivalent Ir sites. In the first Ir site, Ir(1) is bonded in a 5-coordinate geometry to four equivalent U(1), one Si(1), and four equivalent Si(2) atoms. The Ir(1)-Si(1) bond length is 2.36 Å. All Ir(1)-Si(2) bond lengths are 2.42 Å. In the second Ir site, Ir(2) is bonded to four equivalent U(1) and four equivalent Si(1) atoms to form distorted IrU4Si4 tetrahedra that share corners with twelve equivalent Si(2)U4Ir4 tetrahedra, edges with two equivalent Si(2)U4Ir4 tetrahedra, edges with four equivalent Ir(2)U4Si4 tetrahedra, and faces with four equivalent Ir(2)U4Si4 tetrahedra. All Ir(2)-Si(1) bond lengths are 2.44 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 5-coordinate geometry to four equivalent U(1), one Ir(1), and four equivalent Ir(2) atoms. In the second Si site, Si(2) is bonded to four equivalent U(1) and four equivalent Ir(1) atoms to form distorted SiU4Ir4 tetrahedra that share corners with twelve equivalent Ir(2)U4Si4 tetrahedra, edges with two equivalent Ir(2)U4Si4 tetrahedra, edges with four equivalent Si(2)U4Ir4 tetrahedra, and faces with four equivalent Si(2)U4Ir4 tetrahedra.