CaIrSi3 crystallizes in the tetragonal I4mm space group. Ca(1) is bonded in a 16-coordinate geometry to four equivalent Ir(1), four equivalent Si(1), and eight equivalent Si(2) atoms. Ir(1) is bonded in a 5-coordinate geometry to four equivalent Ca(1), one Si(1), and four equivalent Si(2) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to four equivalent Ca(1), one Ir(1), and four equivalent Si(2) atoms. In the second Si site, Si(2) is bonded in a distorted bent 120 degrees geometry to four equivalent Ca(1), two equivalent Ir(1), and two equivalent Si(1) atoms.
CaIrSi3 crystallizes in the tetragonal I4mm space group. Ca(1) is bonded in a 16-coordinate geometry to four equivalent Ir(1), four equivalent Si(1), and eight equivalent Si(2) atoms. All Ca(1)-Ir(1) bond lengths are 3.30 Å. All Ca(1)-Si(1) bond lengths are 3.10 Å. There are four shorter (3.17 Å) and four longer (3.31 Å) Ca(1)-Si(2) bond lengths. Ir(1) is bonded in a 5-coordinate geometry to four equivalent Ca(1), one Si(1), and four equivalent Si(2) atoms. The Ir(1)-Si(1) bond length is 2.35 Å. All Ir(1)-Si(2) bond lengths are 2.37 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to four equivalent Ca(1), one Ir(1), and four equivalent Si(2) atoms. All Si(1)-Si(2) bond lengths are 2.57 Å. In the second Si site, Si(2) is bonded in a distorted bent 120 degrees geometry to four equivalent Ca(1), two equivalent Ir(1), and two equivalent Si(1) atoms.