Ag7Al2Si crystallizes in the monoclinic P2_1 space group. There are seven inequivalent Ag sites. In the first Ag site, Ag(1) is bonded in a 12-coordinate geometry to one Ag(5), one Ag(6), two equivalent Ag(2), two equivalent Ag(3), two equivalent Ag(7), one Al(1), two equivalent Al(2), and one Si(1) atom. In the second Ag site, Ag(2) is bonded in a 12-coordinate geometry to one Ag(3), one Ag(4), two equivalent Ag(1), two equivalent Ag(6), two equivalent Ag(7), one Al(1), two equivalent Al(2), and one Si(1) atom. In the third Ag site, Ag(3) is bonded in a 12-coordinate geometry to one Ag(2), one Ag(4), one Ag(7), two equivalent Ag(1), two equivalent Ag(5), one Al(1), two equivalent Al(2), and two equivalent Si(1) atoms. In the fourth Ag site, Ag(4) is bonded in a 12-coordinate geometry to one Ag(2), one Ag(3), one Ag(7), two equivalent Ag(5), two equivalent Ag(6), one Al(2), two equivalent Al(1), and two equivalent Si(1) atoms. In the fifth Ag site, Ag(5) is bonded in a 12-coordinate geometry to one Ag(1), one Ag(6), one Ag(7), two equivalent Ag(3), two equivalent Ag(4), one Al(2), two equivalent Al(1), and two equivalent Si(1) atoms. In the sixth Ag site, Ag(6) is bonded in a 12-coordinate geometry to one Ag(1), one Ag(5), two equivalent Ag(2), two equivalent Ag(4), two equivalent Ag(7), one Al(2), two equivalent Al(1), and one Si(1) atom. In the seventh Ag site, Ag(7) is bonded in a distorted trigonal planar geometry to one Ag(3), one Ag(4), one Ag(5), two equivalent Ag(1), two equivalent Ag(2), two equivalent Ag(6), one Al(1), and two equivalent Al(2) atoms. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to one Ag(1), one Ag(2), one Ag(3), one Ag(7), two equivalent Ag(4), two equivalent Ag(5), two equivalent Ag(6), and two equivalent Si(1) atoms to form distorted AlSi2Ag10 cuboctahedra that share corners with two equivalent Al(1)Si2Ag10 cuboctahedra, corners with four equivalent Al(2)SiAg11 cuboctahedra, faces with two equivalent Al(1)Si2Ag10 cuboctahedra, and faces with four equivalent Al(2)SiAg11 cuboctahedra. In the second Al site, Al(2) is bonded to one Ag(4), one Ag(5), one Ag(6), two equivalent Ag(1), two equivalent Ag(2), two equivalent Ag(3), two equivalent Ag(7), and one Si(1) atom to form distorted AlSiAg11 cuboctahedra that share corners with two equivalent Al(2)SiAg11 cuboctahedra, corners with four equivalent Al(1)Si2Ag10 cuboctahedra, faces with two equivalent Al(2)SiAg11 cuboctahedra, and faces with four equivalent Al(1)Si2Ag10 cuboctahedra. Si(1) is bonded in a 12-coordinate geometry to one Ag(1), one Ag(2), one Ag(6), two equivalent Ag(3), two equivalent Ag(4), two equivalent Ag(5), one Al(2), and two equivalent Al(1) atoms.
Ag7Al2Si crystallizes in the monoclinic P2_1 space group. There are seven inequivalent Ag sites. In the first Ag site, Ag(1) is bonded in a 12-coordinate geometry to one Ag(5), one Ag(6), two equivalent Ag(2), two equivalent Ag(3), two equivalent Ag(7), one Al(1), two equivalent Al(2), and one Si(1) atom. The Ag(1)-Ag(5) bond length is 2.91 Å. The Ag(1)-Ag(6) bond length is 2.96 Å. There is one shorter (2.94 Å) and one longer (3.00 Å) Ag(1)-Ag(2) bond length. There is one shorter (2.91 Å) and one longer (3.01 Å) Ag(1)-Ag(3) bond length. There is one shorter (2.95 Å) and one longer (2.96 Å) Ag(1)-Ag(7) bond length. The Ag(1)-Al(1) bond length is 2.98 Å. There is one shorter (2.85 Å) and one longer (2.96 Å) Ag(1)-Al(2) bond length. The Ag(1)-Si(1) bond length is 2.80 Å. In the second Ag site, Ag(2) is bonded in a 12-coordinate geometry to one Ag(3), one Ag(4), two equivalent Ag(1), two equivalent Ag(6), two equivalent Ag(7), one Al(1), two equivalent Al(2), and one Si(1) atom. The Ag(2)-Ag(3) bond length is 2.93 Å. The Ag(2)-Ag(4) bond length is 2.97 Å. Both Ag(2)-Ag(6) bond lengths are 2.92 Å. There is one shorter (2.91 Å) and one longer (2.94 Å) Ag(2)-Ag(7) bond length. The Ag(2)-Al(1) bond length is 2.80 Å. There is one shorter (2.92 Å) and one longer (3.06 Å) Ag(2)-Al(2) bond length. The Ag(2)-Si(1) bond length is 2.95 Å. In the third Ag site, Ag(3) is bonded in a 12-coordinate geometry to one Ag(2), one Ag(4), one Ag(7), two equivalent Ag(1), two equivalent Ag(5), one Al(1), two equivalent Al(2), and two equivalent Si(1) atoms. The Ag(3)-Ag(4) bond length is 2.90 Å. The Ag(3)-Ag(7) bond length is 2.93 Å. Both Ag(3)-Ag(5) bond lengths are 2.95 Å. The Ag(3)-Al(1) bond length is 3.02 Å. There is one shorter (2.81 Å) and one longer (2.94 Å) Ag(3)-Al(2) bond length. There is one shorter (2.83 Å) and one longer (2.99 Å) Ag(3)-Si(1) bond length. In the fourth Ag site, Ag(4) is bonded in a 12-coordinate geometry to one Ag(2), one Ag(3), one Ag(7), two equivalent Ag(5), two equivalent Ag(6), one Al(2), two equivalent Al(1), and two equivalent Si(1) atoms. The Ag(4)-Ag(7) bond length is 2.91 Å. There is one shorter (2.91 Å) and one longer (2.96 Å) Ag(4)-Ag(5) bond length. There is one shorter (2.93 Å) and one longer (2.94 Å) Ag(4)-Ag(6) bond length. The Ag(4)-Al(2) bond length is 3.01 Å. There is one shorter (2.79 Å) and one longer (2.96 Å) Ag(4)-Al(1) bond length. There is one shorter (2.96 Å) and one longer (2.99 Å) Ag(4)-Si(1) bond length. In the fifth Ag site, Ag(5) is bonded in a 12-coordinate geometry to one Ag(1), one Ag(6), one Ag(7), two equivalent Ag(3), two equivalent Ag(4), one Al(2), two equivalent Al(1), and two equivalent Si(1) atoms. The Ag(5)-Ag(6) bond length is 3.00 Å. The Ag(5)-Ag(7) bond length is 2.97 Å. The Ag(5)-Al(2) bond length is 2.82 Å. There is one shorter (2.91 Å) and one longer (3.01 Å) Ag(5)-Al(1) bond length. There is one shorter (2.85 Å) and one longer (2.94 Å) Ag(5)-Si(1) bond length. In the sixth Ag site, Ag(6) is bonded in a 12-coordinate geometry to one Ag(1), one Ag(5), two equivalent Ag(2), two equivalent Ag(4), two equivalent Ag(7), one Al(2), two equivalent Al(1), and one Si(1) atom. There is one shorter (2.91 Å) and one longer (2.97 Å) Ag(6)-Ag(7) bond length. The Ag(6)-Al(2) bond length is 2.90 Å. There is one shorter (2.78 Å) and one longer (3.03 Å) Ag(6)-Al(1) bond length. The Ag(6)-Si(1) bond length is 2.92 Å. In the seventh Ag site, Ag(7) is bonded in a distorted trigonal planar geometry to one Ag(3), one Ag(4), one Ag(5), two equivalent Ag(1), two equivalent Ag(2), two equivalent Ag(6), one Al(1), and two equivalent Al(2) atoms. The Ag(7)-Al(1) bond length is 2.62 Å. Both Ag(7)-Al(2) bond lengths are 2.64 Å. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to one Ag(1), one Ag(2), one Ag(3), one Ag(7), two equivalent Ag(4), two equivalent Ag(5), two equivalent Ag(6), and two equivalent Si(1) atoms to form distorted AlSi2Ag10 cuboctahedra that share corners with two equivalent Al(1)Si2Ag10 cuboctahedra, corners with four equivalent Al(2)SiAg11 cuboctahedra, faces with two equivalent Al(1)Si2Ag10 cuboctahedra, and faces with four equivalent Al(2)SiAg11 cuboctahedra. There is one shorter (2.63 Å) and one longer (2.64 Å) Al(1)-Si(1) bond length. In the second Al site, Al(2) is bonded to one Ag(4), one Ag(5), one Ag(6), two equivalent Ag(1), two equivalent Ag(2), two equivalent Ag(3), two equivalent Ag(7), and one Si(1) atom to form distorted AlSiAg11 cuboctahedra that share corners with two equivalent Al(2)SiAg11 cuboctahedra, corners with four equivalent Al(1)Si2Ag10 cuboctahedra, faces with two equivalent Al(2)SiAg11 cuboctahedra, and faces with four equivalent Al(1)Si2Ag10 cuboctahedra. The Al(2)-Si(1) bond length is 2.61 Å. Si(1) is bonded in a 12-coordinate geometry to one Ag(1), one Ag(2), one Ag(6), two equivalent Ag(3), two equivalent Ag(4), two equivalent Ag(5), one Al(2), and two equivalent Al(1) atoms.