CePtSi3 crystallizes in the tetragonal I4mm space group. Ce(1) is bonded in a 17-coordinate geometry to five equivalent Pt(1), four equivalent Si(2), and eight equivalent Si(1) atoms. Pt(1) is bonded in a 5-coordinate geometry to five equivalent Ce(1), one Si(2), and four equivalent Si(1) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a distorted bent 120 degrees geometry to four equivalent Ce(1) and two equivalent Pt(1) atoms. In the second Si site, Si(2) is bonded in a distorted single-bond geometry to four equivalent Ce(1) and one Pt(1) atom.
CePtSi3 crystallizes in the tetragonal I4mm space group. Ce(1) is bonded in a 17-coordinate geometry to five equivalent Pt(1), four equivalent Si(2), and eight equivalent Si(1) atoms. There is one shorter (3.37 Å) and four longer (3.38 Å) Ce(1)-Pt(1) bond lengths. All Ce(1)-Si(2) bond lengths are 3.20 Å. There are four shorter (3.14 Å) and four longer (3.33 Å) Ce(1)-Si(1) bond lengths. Pt(1) is bonded in a 5-coordinate geometry to five equivalent Ce(1), one Si(2), and four equivalent Si(1) atoms. The Pt(1)-Si(2) bond length is 2.41 Å. All Pt(1)-Si(1) bond lengths are 2.42 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a distorted bent 120 degrees geometry to four equivalent Ce(1) and two equivalent Pt(1) atoms. In the second Si site, Si(2) is bonded in a distorted single-bond geometry to four equivalent Ce(1) and one Pt(1) atom.