CaPtSi3 crystallizes in the tetragonal I4mm space group. Ca(1) is bonded in a 16-coordinate geometry to four equivalent Pt(1), four equivalent Si(1), and eight equivalent Si(2) atoms. Pt(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 distorted single-bond geometry to four equivalent Ca(1), one Pt(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 Pt(1), and two equivalent Si(1) atoms.
CaPtSi3 crystallizes in the tetragonal I4mm space group. Ca(1) is bonded in a 16-coordinate geometry to four equivalent Pt(1), four equivalent Si(1), and eight equivalent Si(2) atoms. All Ca(1)-Pt(1) bond lengths are 3.30 Å. All Ca(1)-Si(1) bond lengths are 3.15 Å. There are four shorter (3.18 Å) and four longer (3.32 Å) Ca(1)-Si(2) bond lengths. Pt(1) is bonded in a 5-coordinate geometry to four equivalent Ca(1), one Si(1), and four equivalent Si(2) atoms. The Pt(1)-Si(1) bond length is 2.38 Å. All Pt(1)-Si(2) bond lengths are 2.41 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a distorted single-bond geometry to four equivalent Ca(1), one Pt(1), and four equivalent Si(2) atoms. All Si(1)-Si(2) bond lengths are 2.53 Å. In the second Si site, Si(2) is bonded in a distorted bent 120 degrees geometry to four equivalent Ca(1), two equivalent Pt(1), and two equivalent Si(1) atoms.