Dy2AuAl6Si4 crystallizes in the trigonal R-3m space group. Dy(1) is bonded to three equivalent Si(1) and three equivalent Si(2) atoms to form distorted DySi6 octahedra that share corners with three equivalent Al(2)Si3Au tetrahedra, corners with three equivalent Al(3)SiAu3 tetrahedra, corners with six equivalent Al(1)Si4 tetrahedra, edges with six equivalent Dy(1)Si6 octahedra, edges with three equivalent Al(2)Si3Au tetrahedra, and edges with three equivalent Al(1)Si4 tetrahedra. Au(1) is bonded in a body-centered cubic geometry to two equivalent Al(2) and six equivalent Al(3) atoms. There are three inequivalent Al sites. In the first Al site, Al(1) is bonded to four equivalent Si(2) atoms to form distorted AlSi4 tetrahedra that share corners with six equivalent Dy(1)Si6 octahedra, corners with six equivalent Al(1)Si4 tetrahedra, edges with three equivalent Dy(1)Si6 octahedra, and edges with three equivalent Al(1)Si4 tetrahedra. The corner-sharing octahedral tilt angles range from 20-55°. In the second Al site, Al(2) is bonded to one Au(1) and three equivalent Si(1) atoms to form AlSi3Au tetrahedra that share corners with three equivalent Dy(1)Si6 octahedra, corners with three equivalent Al(3)SiAu3 tetrahedra, corners with seven equivalent Al(2)Si3Au tetrahedra, edges with three equivalent Dy(1)Si6 octahedra, and edges with three equivalent Al(3)SiAu3 tetrahedra. The corner-sharing octahedral tilt angles are 17°. In the third Al site, Al(3) is bonded to three equivalent Au(1) and one Si(1) atom to form distorted AlSiAu3 tetrahedra that share corners with three equivalent Dy(1)Si6 octahedra, corners with three equivalent Al(2)Si3Au tetrahedra, corners with nine equivalent Al(3)SiAu3 tetrahedra, edges with three equivalent Al(2)Si3Au tetrahedra, and edges with three equivalent Al(3)SiAu3 tetrahedra. The corner-sharing octahedral tilt angles are 55°. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to three equivalent Dy(1), one Al(3), and three equivalent Al(2) atoms to form a mixture of distorted corner and edge-sharing SiDy3Al4 pentagonal bipyramids. In the second Si site, Si(2) is bonded to three equivalent Dy(1) and four equivalent Al(1) atoms to form a mixture of distorted corner and edge-sharing SiDy3Al4 pentagonal bipyramids.
Dy2AuAl6Si4 crystallizes in the trigonal R-3m space group. Dy(1) is bonded to three equivalent Si(1) and three equivalent Si(2) atoms to form distorted DySi6 octahedra that share corners with three equivalent Al(2)Si3Au tetrahedra, corners with three equivalent Al(3)SiAu3 tetrahedra, corners with six equivalent Al(1)Si4 tetrahedra, edges with six equivalent Dy(1)Si6 octahedra, edges with three equivalent Al(2)Si3Au tetrahedra, and edges with three equivalent Al(1)Si4 tetrahedra. All Dy(1)-Si(1) bond lengths are 2.96 Å. All Dy(1)-Si(2) bond lengths are 2.97 Å. Au(1) is bonded in a body-centered cubic geometry to two equivalent Al(2) and six equivalent Al(3) atoms. Both Au(1)-Al(2) bond lengths are 2.63 Å. All Au(1)-Al(3) bond lengths are 2.57 Å. There are three inequivalent Al sites. In the first Al site, Al(1) is bonded to four equivalent Si(2) atoms to form distorted AlSi4 tetrahedra that share corners with six equivalent Dy(1)Si6 octahedra, corners with six equivalent Al(1)Si4 tetrahedra, edges with three equivalent Dy(1)Si6 octahedra, and edges with three equivalent Al(1)Si4 tetrahedra. The corner-sharing octahedral tilt angles range from 20-55°. There are three shorter (2.51 Å) and one longer (2.54 Å) Al(1)-Si(2) bond length. In the second Al site, Al(2) is bonded to one Au(1) and three equivalent Si(1) atoms to form AlSi3Au tetrahedra that share corners with three equivalent Dy(1)Si6 octahedra, corners with three equivalent Al(3)SiAu3 tetrahedra, corners with seven equivalent Al(2)Si3Au tetrahedra, edges with three equivalent Dy(1)Si6 octahedra, and edges with three equivalent Al(3)SiAu3 tetrahedra. The corner-sharing octahedral tilt angles are 17°. All Al(2)-Si(1) bond lengths are 2.55 Å. In the third Al site, Al(3) is bonded to three equivalent Au(1) and one Si(1) atom to form distorted AlSiAu3 tetrahedra that share corners with three equivalent Dy(1)Si6 octahedra, corners with three equivalent Al(2)Si3Au tetrahedra, corners with nine equivalent Al(3)SiAu3 tetrahedra, edges with three equivalent Al(2)Si3Au tetrahedra, and edges with three equivalent Al(3)SiAu3 tetrahedra. The corner-sharing octahedral tilt angles are 55°. The Al(3)-Si(1) bond length is 2.58 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to three equivalent Dy(1), one Al(3), and three equivalent Al(2) atoms to form a mixture of distorted corner and edge-sharing SiDy3Al4 pentagonal bipyramids. In the second Si site, Si(2) is bonded to three equivalent Dy(1) and four equivalent Al(1) atoms to form a mixture of distorted corner and edge-sharing SiDy3Al4 pentagonal bipyramids.