Ir4Si5 crystallizes in the monoclinic P2_1/m space group. There are four inequivalent Ir sites. In the first Ir site, Ir(1) is bonded in a 7-coordinate geometry to one Si(3), three equivalent Si(4), and three equivalent Si(5) atoms. In the second Ir site, Ir(2) is bonded in a 6-coordinate geometry to one Si(2), one Si(3), two equivalent Si(1), and two equivalent Si(4) atoms. In the third Ir site, Ir(3) is bonded in a 6-coordinate geometry to three equivalent Si(1) and three equivalent Si(2) atoms. In the fourth Ir site, Ir(4) is bonded in a 7-coordinate geometry to one Si(1), one Si(4), one Si(5), two equivalent Si(2), and two equivalent Si(3) atoms. There are five inequivalent Si sites. In the first Si site, Si(1) is bonded in a 6-coordinate geometry to one Ir(4), two equivalent Ir(2), and three equivalent Ir(3) atoms. In the second Si site, Si(2) is bonded in a 6-coordinate geometry to one Ir(2), two equivalent Ir(4), and three equivalent Ir(3) atoms. In the third Si site, Si(3) is bonded in a 4-coordinate geometry to one Ir(1), one Ir(2), and two equivalent Ir(4) atoms. In the fourth Si site, Si(4) is bonded in a 6-coordinate geometry to one Ir(4), two equivalent Ir(2), and three equivalent Ir(1) atoms. In the fifth Si site, Si(5) is bonded to one Ir(4) and three equivalent Ir(1) atoms to form a mixture of distorted corner and edge-sharing SiIr4 tetrahedra.
Ir4Si5 crystallizes in the monoclinic P2_1/m space group. There are four inequivalent Ir sites. In the first Ir site, Ir(1) is bonded in a 7-coordinate geometry to one Si(3), three equivalent Si(4), and three equivalent Si(5) atoms. The Ir(1)-Si(3) bond length is 2.43 Å. There is one shorter (2.45 Å) and two longer (2.69 Å) Ir(1)-Si(4) bond lengths. There is one shorter (2.46 Å) and two longer (2.49 Å) Ir(1)-Si(5) bond lengths. In the second Ir site, Ir(2) is bonded in a 6-coordinate geometry to one Si(2), one Si(3), two equivalent Si(1), and two equivalent Si(4) atoms. The Ir(2)-Si(2) bond length is 2.45 Å. The Ir(2)-Si(3) bond length is 2.35 Å. Both Ir(2)-Si(1) bond lengths are 2.49 Å. Both Ir(2)-Si(4) bond lengths are 2.49 Å. In the third Ir site, Ir(3) is bonded in a 6-coordinate geometry to three equivalent Si(1) and three equivalent Si(2) atoms. There is one shorter (2.41 Å) and two longer (2.58 Å) Ir(3)-Si(1) bond lengths. There are two shorter (2.42 Å) and one longer (2.46 Å) Ir(3)-Si(2) bond length. In the fourth Ir site, Ir(4) is bonded in a 7-coordinate geometry to one Si(1), one Si(4), one Si(5), two equivalent Si(2), and two equivalent Si(3) atoms. The Ir(4)-Si(1) bond length is 2.58 Å. The Ir(4)-Si(4) bond length is 2.44 Å. The Ir(4)-Si(5) bond length is 2.46 Å. Both Ir(4)-Si(2) bond lengths are 2.74 Å. Both Ir(4)-Si(3) bond lengths are 2.32 Å. There are five inequivalent Si sites. In the first Si site, Si(1) is bonded in a 6-coordinate geometry to one Ir(4), two equivalent Ir(2), and three equivalent Ir(3) atoms. In the second Si site, Si(2) is bonded in a 6-coordinate geometry to one Ir(2), two equivalent Ir(4), and three equivalent Ir(3) atoms. In the third Si site, Si(3) is bonded in a 4-coordinate geometry to one Ir(1), one Ir(2), and two equivalent Ir(4) atoms. In the fourth Si site, Si(4) is bonded in a 6-coordinate geometry to one Ir(4), two equivalent Ir(2), and three equivalent Ir(1) atoms. In the fifth Si site, Si(5) is bonded to one Ir(4) and three equivalent Ir(1) atoms to form a mixture of distorted corner and edge-sharing SiIr4 tetrahedra.