Ca2Pt3Si5 crystallizes in the monoclinic C2/c space group. Ca(1) is bonded in a 17-coordinate geometry to two equivalent Pt(1); five equivalent Pt(2); two equivalent Si(3); four equivalent Si(1); and four Si(2,2) atoms. There are two inequivalent Pt sites. In the first Pt site, Pt(1) is bonded in a 6-coordinate geometry to four equivalent Ca(1); two Si(2,2); and four equivalent Si(1) atoms. In the second Pt site, Pt(2) is bonded in a 5-coordinate geometry to five equivalent Ca(1); one Si(1); two Si(2,2); and two equivalent Si(3) atoms. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to four equivalent Ca(1); one Pt(2); two equivalent Pt(1); and two Si(2,2) atoms. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to four equivalent Ca(1), one Pt(1), two equivalent Pt(2), and two equivalent Si(1) atoms. In the third Si site, Si(2) is bonded in a 9-coordinate geometry to four equivalent Ca(1), one Pt(1), two equivalent Pt(2), and two equivalent Si(1) atoms. In the fourth Si site, Si(3) is bonded in a 8-coordinate geometry to four equivalent Ca(1) and four equivalent Pt(2) atoms.
Ca2Pt3Si5 crystallizes in the monoclinic C2/c space group. Ca(1) is bonded in a 17-coordinate geometry to two equivalent Pt(1); five equivalent Pt(2); two equivalent Si(3); four equivalent Si(1); and four Si(2,2) atoms. There is one shorter (3.40 Å) and one longer (3.41 Å) Ca(1)-Pt(1) bond length. There are a spread of Ca(1)-Pt(2) bond distances ranging from 3.11-3.51 Å. Both Ca(1)-Si(3) bond lengths are 3.15 Å. There are a spread of Ca(1)-Si(1) bond distances ranging from 3.02-3.20 Å. There are two shorter (3.22 Å) and two longer (3.28 Å) Ca(1)-Si(2,2) bond lengths. There are two inequivalent Pt sites. In the first Pt site, Pt(1) is bonded in a 6-coordinate geometry to four equivalent Ca(1); two Si(2,2); and four equivalent Si(1) atoms. Both Pt(1)-Si(2,2) bond lengths are 2.65 Å. There are two shorter (2.47 Å) and two longer (2.48 Å) Pt(1)-Si(1) bond lengths. In the second Pt site, Pt(2) is bonded in a 5-coordinate geometry to five equivalent Ca(1); one Si(1); two Si(2,2); and two equivalent Si(3) atoms. The Pt(2)-Si(1) bond length is 2.38 Å. Both Pt(2)-Si(2,2) bond lengths are 2.44 Å. There is one shorter (2.45 Å) and one longer (2.46 Å) Pt(2)-Si(3) bond length. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to four equivalent Ca(1); one Pt(2); two equivalent Pt(1); and two Si(2,2) atoms. There is one shorter (2.51 Å) and one longer (2.52 Å) Si(1)-Si(2,2) bond length. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to four equivalent Ca(1), one Pt(1), two equivalent Pt(2), and two equivalent Si(1) atoms. In the third Si site, Si(2) is bonded in a 9-coordinate geometry to four equivalent Ca(1), one Pt(1), two equivalent Pt(2), and two equivalent Si(1) atoms. In the fourth Si site, Si(3) is bonded in a 8-coordinate geometry to four equivalent Ca(1) and four equivalent Pt(2) atoms.