Gd2PtAl6Si4 crystallizes in the trigonal R-3m space group. Gd(1) is bonded to three equivalent Si(1) and three equivalent Si(2) atoms to form GdSi6 octahedra that share corners with three equivalent Al(2)Si3Pt tetrahedra, corners with three equivalent Al(1)SiPt3 tetrahedra, corners with six equivalent Al(3)Si4 tetrahedra, edges with six equivalent Gd(1)Si6 octahedra, edges with three equivalent Al(2)Si3Pt tetrahedra, and edges with three equivalent Al(3)Si4 tetrahedra. Pt(1) is bonded in a body-centered cubic geometry to two equivalent Al(2) and six equivalent Al(1) atoms. There are three inequivalent Al sites. In the first Al site, Al(1) is bonded to three equivalent Pt(1) and one Si(2) atom to form distorted AlSiPt3 tetrahedra that share corners with three equivalent Gd(1)Si6 octahedra, corners with three equivalent Al(2)Si3Pt tetrahedra, corners with nine equivalent Al(1)SiPt3 tetrahedra, edges with three equivalent Al(2)Si3Pt tetrahedra, and edges with three equivalent Al(1)SiPt3 tetrahedra. The corner-sharing octahedral tilt angles are 55°. In the second Al site, Al(2) is bonded to one Pt(1) and three equivalent Si(2) atoms to form AlSi3Pt tetrahedra that share corners with three equivalent Gd(1)Si6 octahedra, corners with three equivalent Al(1)SiPt3 tetrahedra, corners with seven equivalent Al(2)Si3Pt tetrahedra, edges with three equivalent Gd(1)Si6 octahedra, and edges with three equivalent Al(1)SiPt3 tetrahedra. The corner-sharing octahedral tilt angles are 15°. In the third Al site, Al(3) is bonded to four equivalent Si(1) atoms to form AlSi4 tetrahedra that share corners with six equivalent Gd(1)Si6 octahedra, corners with six equivalent Al(3)Si4 tetrahedra, edges with three equivalent Gd(1)Si6 octahedra, and edges with three equivalent Al(3)Si4 tetrahedra. The corner-sharing octahedral tilt angles range from 21-53°. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to three equivalent Gd(1) and four equivalent Al(3) atoms to form a mixture of distorted edge and corner-sharing SiGd3Al4 pentagonal bipyramids. In the second Si site, Si(2) is bonded to three equivalent Gd(1), one Al(1), and three equivalent Al(2) atoms to form a mixture of distorted edge and corner-sharing SiGd3Al4 pentagonal bipyramids.
Gd2PtAl6Si4 crystallizes in the trigonal R-3m space group. Gd(1) is bonded to three equivalent Si(1) and three equivalent Si(2) atoms to form GdSi6 octahedra that share corners with three equivalent Al(2)Si3Pt tetrahedra, corners with three equivalent Al(1)SiPt3 tetrahedra, corners with six equivalent Al(3)Si4 tetrahedra, edges with six equivalent Gd(1)Si6 octahedra, edges with three equivalent Al(2)Si3Pt tetrahedra, and edges with three equivalent Al(3)Si4 tetrahedra. All Gd(1)-Si(1) bond lengths are 2.99 Å. All Gd(1)-Si(2) bond lengths are 2.95 Å. Pt(1) is bonded in a body-centered cubic geometry to two equivalent Al(2) and six equivalent Al(1) atoms. Both Pt(1)-Al(2) bond lengths are 2.53 Å. All Pt(1)-Al(1) bond lengths are 2.52 Å. There are three inequivalent Al sites. In the first Al site, Al(1) is bonded to three equivalent Pt(1) and one Si(2) atom to form distorted AlSiPt3 tetrahedra that share corners with three equivalent Gd(1)Si6 octahedra, corners with three equivalent Al(2)Si3Pt tetrahedra, corners with nine equivalent Al(1)SiPt3 tetrahedra, edges with three equivalent Al(2)Si3Pt tetrahedra, and edges with three equivalent Al(1)SiPt3 tetrahedra. The corner-sharing octahedral tilt angles are 55°. The Al(1)-Si(2) bond length is 2.65 Å. In the second Al site, Al(2) is bonded to one Pt(1) and three equivalent Si(2) atoms to form AlSi3Pt tetrahedra that share corners with three equivalent Gd(1)Si6 octahedra, corners with three equivalent Al(1)SiPt3 tetrahedra, corners with seven equivalent Al(2)Si3Pt tetrahedra, edges with three equivalent Gd(1)Si6 octahedra, and edges with three equivalent Al(1)SiPt3 tetrahedra. The corner-sharing octahedral tilt angles are 15°. All Al(2)-Si(2) bond lengths are 2.56 Å. In the third Al site, Al(3) is bonded to four equivalent Si(1) atoms to form AlSi4 tetrahedra that share corners with six equivalent Gd(1)Si6 octahedra, corners with six equivalent Al(3)Si4 tetrahedra, edges with three equivalent Gd(1)Si6 octahedra, and edges with three equivalent Al(3)Si4 tetrahedra. The corner-sharing octahedral tilt angles range from 21-53°. There are three shorter (2.49 Å) and one longer (2.55 Å) Al(3)-Si(1) bond length. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to three equivalent Gd(1) and four equivalent Al(3) atoms to form a mixture of distorted edge and corner-sharing SiGd3Al4 pentagonal bipyramids. In the second Si site, Si(2) is bonded to three equivalent Gd(1), one Al(1), and three equivalent Al(2) atoms to form a mixture of distorted edge and corner-sharing SiGd3Al4 pentagonal bipyramids.