MgIr3Si7 crystallizes in the trigonal R-3c space group. Mg(1) is bonded in a 18-coordinate geometry to six equivalent Ir(1) and twelve equivalent Si(1) atoms. Ir(1) is bonded in a 9-coordinate geometry to two equivalent Mg(1), one Si(2), and six equivalent Si(1) atoms. There are two inequivalent Si sites. In the first Si site, Si(2) is bonded in a distorted trigonal planar geometry to three equivalent Ir(1) atoms. In the second Si site, Si(1) is bonded in a 3-coordinate geometry to two equivalent Mg(1) and three equivalent Ir(1) atoms.
MgIr3Si7 crystallizes in the trigonal R-3c space group. Mg(1) is bonded in a 18-coordinate geometry to six equivalent Ir(1) and twelve equivalent Si(1) atoms. All Mg(1)-Ir(1) bond lengths are 3.04 Å. There are six shorter (3.10 Å) and six longer (3.17 Å) Mg(1)-Si(1) bond lengths. Ir(1) is bonded in a 9-coordinate geometry to two equivalent Mg(1), one Si(2), and six equivalent Si(1) atoms. The Ir(1)-Si(2) bond length is 2.44 Å. There are a spread of Ir(1)-Si(1) bond distances ranging from 2.42-2.50 Å. There are two inequivalent Si sites. In the first Si site, Si(2) is bonded in a distorted trigonal planar geometry to three equivalent Ir(1) atoms. In the second Si site, Si(1) is bonded in a 3-coordinate geometry to two equivalent Mg(1) and three equivalent Ir(1) atoms.