Sm2PtSi3 is hexagonal omega structure-derived structured and crystallizes in the orthorhombic Imm2 space group. There are two inequivalent Sm sites. In the first Sm site, Sm(1) is bonded to two equivalent Pt(1), two equivalent Si(3), four equivalent Si(1), and four equivalent Si(2) atoms to form SmSi10Pt2 cuboctahedra that share edges with four equivalent Sm(1)Si10Pt2 cuboctahedra, edges with eight equivalent Sm(2)Si8Pt4 cuboctahedra, faces with four equivalent Sm(1)Si10Pt2 cuboctahedra, and faces with four equivalent Sm(2)Si8Pt4 cuboctahedra. In the second Sm site, Sm(2) is bonded to four equivalent Pt(1), two equivalent Si(1), two equivalent Si(2), and four equivalent Si(3) atoms to form SmSi8Pt4 cuboctahedra that share edges with four equivalent Sm(2)Si8Pt4 cuboctahedra, edges with eight equivalent Sm(1)Si10Pt2 cuboctahedra, faces with four equivalent Sm(1)Si10Pt2 cuboctahedra, and faces with four equivalent Sm(2)Si8Pt4 cuboctahedra. Pt(1) is bonded in a 9-coordinate geometry to two equivalent Sm(1), four equivalent Sm(2), one Si(3), and two equivalent Si(2) atoms. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to two equivalent Sm(2), four equivalent Sm(1), one Si(2), and two equivalent Si(3) atoms. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to two equivalent Sm(2), four equivalent Sm(1), two equivalent Pt(1), and one Si(1) atom. In the third Si site, Si(3) is bonded in a distorted single-bond geometry to two equivalent Sm(1), four equivalent Sm(2), one Pt(1), and two equivalent Si(1) atoms.
Sm2PtSi3 is hexagonal omega structure-derived structured and crystallizes in the orthorhombic Imm2 space group. There are two inequivalent Sm sites. In the first Sm site, Sm(1) is bonded to two equivalent Pt(1), two equivalent Si(3), four equivalent Si(1), and four equivalent Si(2) atoms to form SmSi10Pt2 cuboctahedra that share edges with four equivalent Sm(1)Si10Pt2 cuboctahedra, edges with eight equivalent Sm(2)Si8Pt4 cuboctahedra, faces with four equivalent Sm(1)Si10Pt2 cuboctahedra, and faces with four equivalent Sm(2)Si8Pt4 cuboctahedra. Both Sm(1)-Pt(1) bond lengths are 3.15 Å. Both Sm(1)-Si(3) bond lengths are 3.16 Å. All Sm(1)-Si(1) bond lengths are 3.12 Å. All Sm(1)-Si(2) bond lengths are 3.18 Å. In the second Sm site, Sm(2) is bonded to four equivalent Pt(1), two equivalent Si(1), two equivalent Si(2), and four equivalent Si(3) atoms to form SmSi8Pt4 cuboctahedra that share edges with four equivalent Sm(2)Si8Pt4 cuboctahedra, edges with eight equivalent Sm(1)Si10Pt2 cuboctahedra, faces with four equivalent Sm(1)Si10Pt2 cuboctahedra, and faces with four equivalent Sm(2)Si8Pt4 cuboctahedra. All Sm(2)-Pt(1) bond lengths are 3.17 Å. Both Sm(2)-Si(1) bond lengths are 3.17 Å. Both Sm(2)-Si(2) bond lengths are 3.14 Å. All Sm(2)-Si(3) bond lengths are 3.13 Å. Pt(1) is bonded in a 9-coordinate geometry to two equivalent Sm(1), four equivalent Sm(2), one Si(3), and two equivalent Si(2) atoms. The Pt(1)-Si(3) bond length is 2.35 Å. Both Pt(1)-Si(2) bond lengths are 2.39 Å. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to two equivalent Sm(2), four equivalent Sm(1), one Si(2), and two equivalent Si(3) atoms. The Si(1)-Si(2) bond length is 2.35 Å. Both Si(1)-Si(3) bond lengths are 2.40 Å. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to two equivalent Sm(2), four equivalent Sm(1), two equivalent Pt(1), and one Si(1) atom. In the third Si site, Si(3) is bonded in a distorted single-bond geometry to two equivalent Sm(1), four equivalent Sm(2), one Pt(1), and two equivalent Si(1) atoms.