Al4Si19 is beta beryllia-like structured and crystallizes in the triclinic P1 space group. There are eight inequivalent Al sites. In the first Al site, Al(1) is bonded to one Si(20), one Si(22), one Si(35), and one Si(37) atom to form AlSi4 tetrahedra that share  a cornercorner with one Al(4)Si4 tetrahedra,  a cornercorner with one Si(5)Al2Si2 tetrahedra,  a cornercorner with one Si(12)AlSi3 tetrahedra,  a cornercorner with one Si(17)AlSi3 tetrahedra,  a cornercorner with one Si(11)Si4 tetrahedra,  a cornercorner with one Si(14)Si4 tetrahedra,  a cornercorner with one Si(18)Si4 tetrahedra,  a cornercorner with one Si(21)Si4 tetrahedra,  a cornercorner with one Si(36)Si4 tetrahedra,  a cornercorner with one Si(38)Si4 tetrahedra,  a cornercorner with one Si(7)Si4 tetrahedra, and  a cornercorner with one Si(8)Si4 tetrahedra. In the second Al site, Al(2) is bonded to one Si(24), one Si(25), one Si(33), and one Si(34) atom to form AlSi4 tetrahedra that share  a cornercorner with one Al(5)Si4 tetrahedra,  a cornercorner with one Al(8)Si4 tetrahedra,  a cornercorner with one Si(10)AlSi3 tetrahedra,  a cornercorner with one Si(12)AlSi3 tetrahedra,  a cornercorner with one Si(17)AlSi3 tetrahedra,  a cornercorner with one Si(11)Si4 tetrahedra,  a cornercorner with one Si(13)Si4 tetrahedra,  a cornercorner with one Si(16)Si4 tetrahedra,  a cornercorner with one Si(23)Si4 tetrahedra,  a cornercorner with one Si(32)Si4 tetrahedra,  a cornercorner with one Si(6)Si4 tetrahedra, and  a cornercorner with one Si(7)Si4 tetrahedra. In the third Al site, Al(3) is bonded to one Si(26), one Si(28), one Si(30), and one Si(31) atom to form AlSi4 tetrahedra that share  a cornercorner with one Al(6)Si4 tetrahedra,  a cornercorner with one Al(7)Si4 tetrahedra,  a cornercorner with one Si(4)AlSi3 tetrahedra,  a cornercorner with one Si(9)AlSi3 tetrahedra,  a cornercorner with one Si(11)Si4 tetrahedra,  a cornercorner with one Si(13)Si4 tetrahedra,  a cornercorner with one Si(14)Si4 tetrahedra,  a cornercorner with one Si(16)Si4 tetrahedra,  a cornercorner with one Si(18)Si4 tetrahedra,  a cornercorner with one Si(27)Si4 tetrahedra,  a cornercorner with one Si(29)Si4 tetrahedra, and  a cornercorner with one Si(7)Si4 tetrahedra. In the fourth Al site, Al(4) is bonded to one Si(1), one Si(15), one Si(20), and one Si(4) atom to form AlSi4 tetrahedra that share  a cornercorner with one Al(1)Si4 tetrahedra,  a cornercorner with one Al(5)Si4 tetrahedra,  a cornercorner with one Si(5)Al2Si2 tetrahedra,  a cornercorner with one Si(19)AlSi3 tetrahedra,  a cornercorner with one Si(26)AlSi3 tetrahedra,  a cornercorner with one Si(9)AlSi3 tetrahedra,  a cornercorner with one Si(14)Si4 tetrahedra,  a cornercorner with one Si(21)Si4 tetrahedra,  a cornercorner with one Si(23)Si4 tetrahedra,  a cornercorner with one Si(27)Si4 tetrahedra,  a cornercorner with one Si(36)Si4 tetrahedra, and  a cornercorner with one Si(38)Si4 tetrahedra. In the fifth Al site, Al(5) is bonded to one Si(15), one Si(2), one Si(25), and one Si(5) atom to form AlSi4 tetrahedra that share  a cornercorner with one Al(2)Si4 tetrahedra,  a cornercorner with one Al(4)Si4 tetrahedra,  a cornercorner with one Al(6)Si4 tetrahedra,  a cornercorner with one Al(8)Si4 tetrahedra,  a cornercorner with one Si(20)Al2Si2 tetrahedra,  a cornercorner with one Si(12)AlSi3 tetrahedra,  a cornercorner with one Si(19)AlSi3 tetrahedra,  a cornercorner with one Si(23)Si4 tetrahedra,  a cornercorner with one Si(27)Si4 tetrahedra,  a cornercorner with one Si(32)Si4 tetrahedra,  a cornercorner with one Si(6)Si4 tetrahedra, and  a cornercorner with one Si(8)Si4 tetrahedra. In the sixth Al site, Al(6) is bonded to one Si(12), one Si(28), one Si(3), and one Si(5) atom to form AlSi4 tetrahedra that share  a cornercorner with one Al(3)Si4 tetrahedra,  a cornercorner with one Al(5)Si4 tetrahedra,  a cornercorner with one Al(7)Si4 tetrahedra,  a cornercorner with one Si(20)Al2Si2 tetrahedra,  a cornercorner with one Si(25)Al2Si2 tetrahedra,  a cornercorner with one Si(17)AlSi3 tetrahedra,  a cornercorner with one Si(22)AlSi3 tetrahedra,  a cornercorner with one Si(14)Si4 tetrahedra,  a cornercorner with one Si(27)Si4 tetrahedra,  a cornercorner with one Si(29)Si4 tetrahedra,  a cornercorner with one Si(7)Si4 tetrahedra, and  a cornercorner with one Si(8)Si4 tetrahedra. In the seventh Al site, Al(7) is bonded to one Si(10), one Si(17), one Si(3), and one Si(31) atom to form AlSi4 tetrahedra that share  a cornercorner with one Al(3)Si4 tetrahedra,  a cornercorner with one Al(6)Si4 tetrahedra,  a cornercorner with one Si(34)Al2Si2 tetrahedra,  a cornercorner with one Si(12)AlSi3 tetrahedra,  a cornercorner with one Si(33)AlSi3 tetrahedra,  a cornercorner with one Si(35)AlSi3 tetrahedra,  a cornercorner with one Si(11)Si4 tetrahedra,  a cornercorner with one Si(16)Si4 tetrahedra,  a cornercorner with one Si(27)Si4 tetrahedra,  a cornercorner with one Si(29)Si4 tetrahedra,  a cornercorner with one Si(36)Si4 tetrahedra, and  a cornercorner with one Si(6)Si4 tetrahedra. In the eighth Al site, Al(8) is bonded to one Si(19), one Si(2), one Si(34), and one Si(9) atom to form AlSi4 tetrahedra that share  a cornercorner with one Al(2)Si4 tetrahedra,  a cornercorner with one Al(5)Si4 tetrahedra,  a cornercorner with one Si(15)Al2Si2 tetrahedra,  a cornercorner with one Si(10)AlSi3 tetrahedra,  a cornercorner with one Si(30)AlSi3 tetrahedra,  a cornercorner with one Si(4)AlSi3 tetrahedra,  a cornercorner with one Si(16)Si4 tetrahedra,  a cornercorner with one Si(23)Si4 tetrahedra,  a cornercorner with one Si(29)Si4 tetrahedra,  a cornercorner with one Si(32)Si4 tetrahedra,  a cornercorner with one Si(36)Si4 tetrahedra, and  a cornercorner with one Si(38)Si4 tetrahedra. There are thirty-eight inequivalent Si sites. In the first Si site, Si(1) is bonded to one Al(4), one Si(21), one Si(36), and one Si(38) atom to form SiAlSi3 tetrahedra that share  a cornercorner with one Si(15)Al2Si2 tetrahedra,  a cornercorner with one Si(20)Al2Si2 tetrahedra,  a cornercorner with one Si(10)AlSi3 tetrahedra,  a cornercorner with one Si(19)AlSi3 tetrahedra,  a cornercorner with one Si(22)AlSi3 tetrahedra,  a cornercorner with one Si(35)AlSi3 tetrahedra,  a cornercorner with one Si(37)AlSi3 tetrahedra,  a cornercorner with one Si(4)AlSi3 tetrahedra,  a cornercorner with one Si(9)AlSi3 tetrahedra,  a cornercorner with one Si(13)Si4 tetrahedra,  a cornercorner with one Si(16)Si4 tetrahedra, and  a cornercorner with one Si(6)Si4 tetrahedra. In the second Si site, Si(2) is bonded to one Al(5), one Al(8), one Si(23), and one Si(32) atom to form SiAl2Si2 tetrahedra that share  a cornercorner with one Si(15)Al2Si2 tetrahedra,  a cornercorner with one Si(25)Al2Si2 tetrahedra,  a cornercorner with one Si(34)Al2Si2 tetrahedra,  a cornercorner with one Si(5)Al2Si2 tetrahedra,  a cornercorner with one Si(19)AlSi3 tetrahedra,  a cornercorner with one Si(24)AlSi3 tetrahedra,  a cornercorner with one Si(33)AlSi3 tetrahedra,  a cornercorner with one Si(4)AlSi3 tetrahedra,  a cornercorner with one Si(9)AlSi3 tetrahedra,  a cornercorner with one Si(14)Si4 tetrahedra,  a cornercorner with one Si(18)Si4 tetrahedra, and  a cornercorner with one Si(8)Si4 tetrahedra. In the third Si site, Si(3) is bonded to one Al(6), one Al(7), one Si(27), and one Si(29) atom to form SiAl2Si2 tetrahedra that share  a cornercorner with one Si(15)Al2Si2 tetrahedra,  a cornercorner with one Si(28)Al2Si2 tetrahedra,  a cornercorner with one Si(31)Al2Si2 tetrahedra,  a cornercorner with one Si(5)Al2Si2 tetrahedra,  a cornercorner with one Si(10)AlSi3 tetrahedra,  a cornercorner with one Si(12)AlSi3 tetrahedra,  a cornercorner with one Si(17)AlSi3 tetrahedra,  a cornercorner with one Si(19)AlSi3 tetrahedra,  a cornercorner with one Si(26)AlSi3 tetrahedra,  a cornercorner with one Si(30)AlSi3 tetrahedra,  a cornercorner with one Si(6)Si4 tetrahedra, and  a cornercorner with one Si(8)Si4 tetrahedra. In the fourth Si site, Si(4) is bonded to one Al(4), one Si(23), one Si(26), and one Si(9) atom to form SiAlSi3 tetrahedra that share  a cornercorner with one Al(3)Si4 tetrahedra,  a cornercorner with one Al(8)Si4 tetrahedra,  a cornercorner with one Si(15)Al2Si2 tetrahedra,  a cornercorner with one Si(2)Al2Si2 tetrahedra,  a cornercorner with one Si(20)Al2Si2 tetrahedra,  a cornercorner with one Si(1)AlSi3 tetrahedra,  a cornercorner with one Si(24)AlSi3 tetrahedra,  a cornercorner with one Si(30)AlSi3 tetrahedra,  a cornercorner with one Si(13)Si4 tetrahedra,  a cornercorner with one Si(14)Si4 tetrahedra,  a cornercorner with one Si(27)Si4 tetrahedra, and  a cornercorner with one Si(38)Si4 tetrahedra. In the fifth Si site, Si(5) is bonded to one Al(5), one Al(6), one Si(20), and one Si(8) atom to form SiAl2Si2 tetrahedra that share  a cornercorner with one Al(1)Si4 tetrahedra,  a cornercorner with one Al(4)Si4 tetrahedra,  a cornercorner with one Si(15)Al2Si2 tetrahedra,  a cornercorner with one Si(2)Al2Si2 tetrahedra,  a cornercorner with one Si(25)Al2Si2 tetrahedra,  a cornercorner with one Si(28)Al2Si2 tetrahedra,  a cornercorner with one Si(3)Al2Si2 tetrahedra,  a cornercorner with one Si(12)AlSi3 tetrahedra,  a cornercorner with one Si(35)AlSi3 tetrahedra,  a cornercorner with one Si(14)Si4 tetrahedra,  a cornercorner with one Si(29)Si4 tetrahedra, and  a cornercorner with one Si(32)Si4 tetrahedra. In the sixth Si site, Si(6) is bonded to one Si(10), one Si(21), one Si(25), and one Si(27) atom to form SiSi4 tetrahedra that share  a cornercorner with one Al(2)Si4 tetrahedra,  a cornercorner with one Al(5)Si4 tetrahedra,  a cornercorner with one Al(7)Si4 tetrahedra,  a cornercorner with one Si(15)Al2Si2 tetrahedra,  a cornercorner with one Si(3)Al2Si2 tetrahedra,  a cornercorner with one Si(34)Al2Si2 tetrahedra,  a cornercorner with one Si(1)AlSi3 tetrahedra,  a cornercorner with one Si(12)AlSi3 tetrahedra,  a cornercorner with one Si(22)AlSi3 tetrahedra,  a cornercorner with one Si(26)AlSi3 tetrahedra,  a cornercorner with one Si(13)Si4 tetrahedra, and  a cornercorner with one Si(36)Si4 tetrahedra. In the seventh Si site, Si(7) is bonded to one Si(11), one Si(22), one Si(24), and one Si(28) atom to form SiSi4 tetrahedra that share  a cornercorner with one Al(1)Si4 tetrahedra,  a cornercorner with one Al(2)Si4 tetrahedra,  a cornercorner with one Al(3)Si4 tetrahedra,  a cornercorner with one Al(6)Si4 tetrahedra,  a cornercorner with one Si(31)Al2Si2 tetrahedra,  a cornercorner with one Si(12)AlSi3 tetrahedra,  a cornercorner with one Si(33)AlSi3 tetrahedra,  a cornercorner with one Si(37)AlSi3 tetrahedra,  a cornercorner with one Si(13)Si4 tetrahedra,  a cornercorner with one Si(14)Si4 tetrahedra,  a cornercorner with one Si(21)Si4 tetrahedra, and  a cornercorner with one Si(23)Si4 tetrahedra. In the eighth Si site, Si(8) is bonded to one Si(29), one Si(32), one Si(35), and one Si(5) atom to form SiSi4 tetrahedra that share  a cornercorner with one Al(1)Si4 tetrahedra,  a cornercorner with one Al(5)Si4 tetrahedra,  a cornercorner with one Al(6)Si4 tetrahedra,  a cornercorner with one Si(2)Al2Si2 tetrahedra,  a cornercorner with one Si(20)Al2Si2 tetrahedra,  a cornercorner with one Si(3)Al2Si2 tetrahedra,  a cornercorner with one Si(17)AlSi3 tetrahedra,  a cornercorner with one Si(19)AlSi3 tetrahedra,  a cornercorner with one Si(30)AlSi3 tetrahedra,  a cornercorner with one Si(33)AlSi3 tetrahedra,  a cornercorner with one Si(18)Si4 tetrahedra, and  a cornercorner with one Si(36)Si4 tetrahedra. In the ninth Si site, Si(9) is bonded to one Al(8), one Si(30), one Si(38), and one Si(4) atom to form SiAlSi3 tetrahedra that share  a cornercorner with one Al(3)Si4 tetrahedra,  a cornercorner with one Al(4)Si4 tetrahedra,  a cornercorner with one Si(2)Al2Si2 tetrahedra,  a cornercorner with one Si(34)Al2Si2 tetrahedra,  a cornercorner with one Si(1)AlSi3 tetrahedra,  a cornercorner with one Si(19)AlSi3 tetrahedra,  a cornercorner with one Si(26)AlSi3 tetrahedra,  a cornercorner with one Si(37)AlSi3 tetrahedra,  a cornercorner with one Si(16)Si4 tetrahedra,  a cornercorner with one Si(18)Si4 tetrahedra,  a cornercorner with one Si(23)Si4 tetrahedra, and  a cornercorner with one Si(29)Si4 tetrahedra. In the tenth Si site, Si(10) is bonded to one Al(7), one Si(34), one Si(36), and one Si(6) atom to form SiAlSi3 tetrahedra that share  a cornercorner with one Al(2)Si4 tetrahedra,  a cornercorner with one Al(8)Si4 tetrahedra,  a cornercorner with one Si(25)Al2Si2 tetrahedra,  a cornercorner with one Si(3)Al2Si2 tetrahedra,  a cornercorner with one Si(31)Al2Si2 tetrahedra,  a cornercorner with one Si(1)AlSi3 tetrahedra,  a cornercorner with one Si(17)AlSi3 tetrahedra,  a cornercorner with one Si(19)AlSi3 tetrahedra,  a cornercorner with one Si(35)AlSi3 tetrahedra,  a cornercorner with one Si(16)Si4 tetrahedra,  a cornercorner with one Si(21)Si4 tetrahedra, and  a cornercorner with one Si(27)Si4 tetrahedra. In the eleventh Si site, Si(11) is bonded to one Si(31), one Si(33), one Si(37), and one Si(7) atom to form SiSi4 tetrahedra that share  a cornercorner with one Al(1)Si4 tetrahedra,  a cornercorner with one Al(2)Si4 tetrahedra,  a cornercorner with one Al(3)Si4 tetrahedra,  a cornercorner with one Al(7)Si4 tetrahedra,  a cornercorner with one Si(28)Al2Si2 tetrahedra,  a cornercorner with one Si(17)AlSi3 tetrahedra,  a cornercorner with one Si(22)AlSi3 tetrahedra,  a cornercorner with one Si(24)AlSi3 tetrahedra,  a cornercorner with one Si(16)Si4 tetrahedra,  a cornercorner with one Si(18)Si4 tetrahedra,  a cornercorner with one Si(32)Si4 tetrahedra, and  a cornercorner with one Si(38)Si4 tetrahedra. In the twelfth Si site, Si(12) is bonded to one Al(6), one Si(17), one Si(22), and one Si(25) atom to form SiAlSi3 tetrahedra that share  a cornercorner with one Al(1)Si4 tetrahedra,  a cornercorner with one Al(2)Si4 tetrahedra,  a cornercorner with one Al(5)Si4 tetrahedra,  a cornercorner with one Al(7)Si4 tetrahedra,  a cornercorner with one Si(28)Al2Si2 tetrahedra,  a cornercorner with one Si(3)Al2Si2 tetrahedra,  a cornercorner with one Si(5)Al2Si2 tetrahedra,  a cornercorner with one Si(33)AlSi3 tetrahedra,  a cornercorner with one Si(35)AlSi3 tetrahedra,  a cornercorner with one Si(21)Si4 tetrahedra,  a cornercorner with one Si(6)Si4 tetrahedra, and  a cornercorner with one Si(7)Si4 tetrahedra. In the thirteenth Si site, Si(13) is bonded to one Si(16), one Si(21), one Si(24), and one Si(26) atom to form SiSi4 tetrahedra that share  a cornercorner with one Al(2)Si4 tetrahedra,  a cornercorner with one Al(3)Si4 tetrahedra,  a cornercorner with one Si(31)Al2Si2 tetrahedra,  a cornercorner with one Si(34)Al2Si2 tetrahedra,  a cornercorner with one Si(1)AlSi3 tetrahedra,  a cornercorner with one Si(22)AlSi3 tetrahedra,  a cornercorner with one Si(4)AlSi3 tetrahedra,  a cornercorner with one Si(23)Si4 tetrahedra,  a cornercorner with one Si(27)Si4 tetrahedra,  a cornercorner with one Si(38)Si4 tetrahedra,  a cornercorner with one Si(6)Si4 tetrahedra, and  a cornercorner with one Si(7)Si4 tetrahedra. In the fourteenth Si site, Si(14) is bonded to one Si(18), one Si(20), one Si(23), and one Si(28) atom to form SiSi4 tetrahedra that share  a cornercorner with one Al(1)Si4 tetrahedra,  a cornercorner with one Al(3)Si4 tetrahedra,  a cornercorner with one Al(4)Si4 tetrahedra,  a cornercorner with one Al(6)Si4 tetrahedra,  a cornercorner with one Si(2)Al2Si2 tetrahedra,  a cornercorner with one Si(5)Al2Si2 tetrahedra,  a cornercorner with one Si(24)AlSi3 tetrahedra,  a cornercorner with one Si(30)AlSi3 tetrahedra,  a cornercorner with one Si(37)AlSi3 tetrahedra,  a cornercorner with one Si(4)AlSi3 tetrahedra,  a cornercorner with one Si(32)Si4 tetrahedra, and  a cornercorner with one Si(7)Si4 tetrahedra. In the fifteenth Si site, Si(15) is bonded to one Al(4), one Al(5), one Si(19), and one Si(27) atom to form SiAl2Si2 tetrahedra that share  a cornercorner with one Al(8)Si4 tetrahedra,  a cornercorner with one Si(2)Al2Si2 tetrahedra,  a cornercorner with one Si(20)Al2Si2 tetrahedra,  a cornercorner with one Si(25)Al2Si2 tetrahedra,  a cornercorner with one Si(3)Al2Si2 tetrahedra,  a cornercorner with one Si(5)Al2Si2 tetrahedra,  a cornercorner with one Si(1)AlSi3 tetrahedra,  a cornercorner with one Si(26)AlSi3 tetrahedra,  a cornercorner with one Si(4)AlSi3 tetrahedra,  a cornercorner with one Si(29)Si4 tetrahedra,  a cornercorner with one Si(36)Si4 tetrahedra, and  a cornercorner with one Si(6)Si4 tetrahedra. In the sixteenth Si site, Si(16) is bonded to one Si(13), one Si(31), one Si(34), and one Si(38) atom to form SiSi4 tetrahedra that share  a cornercorner with one Al(2)Si4 tetrahedra,  a cornercorner with one Al(3)Si4 tetrahedra,  a cornercorner with one Al(7)Si4 tetrahedra,  a cornercorner with one Al(8)Si4 tetrahedra,  a cornercorner with one Si(1)AlSi3 tetrahedra,  a cornercorner with one Si(10)AlSi3 tetrahedra,  a cornercorner with one Si(24)AlSi3 tetrahedra,  a cornercorner with one Si(26)AlSi3 tetrahedra,  a cornercorner with one Si(37)AlSi3 tetrahedra,  a cornercorner with one Si(9)AlSi3 tetrahedra,  a cornercorner with one Si(11)Si4 tetrahedra, and  a cornercorner with one Si(21)Si4 tetrahedra. In the seventeenth Si site, Si(17) is bonded to one Al(7), one Si(12), one Si(33), and one Si(35) atom to form SiAlSi3 tetrahedra that share  a cornercorner with one Al(1)Si4 tetrahedra,  a cornercorner with one Al(2)Si4 tetrahedra,  a cornercorner with one Al(6)Si4 tetrahedra,  a cornercorner with one Si(25)Al2Si2 tetrahedra,  a cornercorner with one Si(3)Al2Si2 tetrahedra,  a cornercorner with one Si(31)Al2Si2 tetrahedra,  a cornercorner with one Si(10)AlSi3 tetrahedra,  a cornercorner with one Si(22)AlSi3 tetrahedra,  a cornercorner with one Si(11)Si4 tetrahedra,  a cornercorner with one Si(32)Si4 tetrahedra,  a cornercorner with one Si(36)Si4 tetrahedra, and  a cornercorner with one Si(8)Si4 tetrahedra. In the eighteenth Si site, Si(18) is bonded to one Si(14), one Si(30), one Si(32), and one Si(37) atom to form SiSi4 tetrahedra that share  a cornercorner with one Al(1)Si4 tetrahedra,  a cornercorner with one Al(3)Si4 tetrahedra,  a cornercorner with one Si(2)Al2Si2 tetrahedra,  a cornercorner with one Si(20)Al2Si2 tetrahedra,  a cornercorner with one Si(28)Al2Si2 tetrahedra,  a cornercorner with one Si(33)AlSi3 tetrahedra,  a cornercorner with one Si(9)AlSi3 tetrahedra,  a cornercorner with one Si(11)Si4 tetrahedra,  a cornercorner with one Si(23)Si4 tetrahedra,  a cornercorner with one Si(29)Si4 tetrahedra,  a cornercorner with one Si(38)Si4 tetrahedra, and  a cornercorner with one Si(8)Si4 tetrahedra. In the nineteenth Si site, Si(19) is bonded to one Al(8), one Si(15), one Si(29), and one Si(36) atom to form SiAlSi3 tetrahedra that share  a cornercorner with one Al(4)Si4 tetrahedra,  a cornercorner with one Al(5)Si4 tetrahedra,  a cornercorner with one Si(2)Al2Si2 tetrahedra,  a cornercorner with one Si(3)Al2Si2 tetrahedra,  a cornercorner with one Si(34)Al2Si2 tetrahedra,  a cornercorner with one Si(1)AlSi3 tetrahedra,  a cornercorner with one Si(10)AlSi3 tetrahedra,  a cornercorner with one Si(30)AlSi3 tetrahedra,  a cornercorner with one Si(35)AlSi3 tetrahedra,  a cornercorner with one Si(9)AlSi3 tetrahedra,  a cornercorner with one Si(27)Si4 tetrahedra, and  a cornercorner with one Si(8)Si4 tetrahedra. In the twentieth Si site, Si(20) is bonded to one Al(1), one Al(4), one Si(14), and one Si(5) atom to form SiAl2Si2 tetrahedra that share  a cornercorner with one Al(5)Si4 tetrahedra,  a cornercorner with one Al(6)Si4 tetrahedra,  a cornercorner with one Si(15)Al2Si2 tetrahedra,  a cornercorner with one Si(28)Al2Si2 tetrahedra,  a cornercorner with one Si(1)AlSi3 tetrahedra,  a cornercorner with one Si(22)AlSi3 tetrahedra,  a cornercorner with one Si(35)AlSi3 tetrahedra,  a cornercorner with one Si(37)AlSi3 tetrahedra,  a cornercorner with one Si(4)AlSi3 tetrahedra,  a cornercorner with one Si(18)Si4 tetrahedra,  a cornercorner with one Si(23)Si4 tetrahedra, and  a cornercorner with one Si(8)Si4 tetrahedra. In the twenty-first Si site, Si(21) is bonded to one Si(1), one Si(13), one Si(22), and one Si(6) atom to form SiSi4 tetrahedra that share  a cornercorner with one Al(1)Si4 tetrahedra,  a cornercorner with one Al(4)Si4 tetrahedra,  a cornercorner with one Si(25)Al2Si2 tetrahedra,  a cornercorner with one Si(10)AlSi3 tetrahedra,  a cornercorner with one Si(12)AlSi3 tetrahedra,  a cornercorner with one Si(24)AlSi3 tetrahedra,  a cornercorner with one Si(26)AlSi3 tetrahedra,  a cornercorner with one Si(16)Si4 tetrahedra,  a cornercorner with one Si(27)Si4 tetrahedra,  a cornercorner with one Si(36)Si4 tetrahedra,  a cornercorner with one Si(38)Si4 tetrahedra, and  a cornercorner with one Si(7)Si4 tetrahedra. In the twenty-second Si site, Si(22) is bonded to one Al(1), one Si(12), one Si(21), and one Si(7) atom to form distorted SiAlSi3 tetrahedra that share  a cornercorner with one Al(6)Si4 tetrahedra,  a cornercorner with one Si(20)Al2Si2 tetrahedra,  a cornercorner with one Si(25)Al2Si2 tetrahedra,  a cornercorner with one Si(28)Al2Si2 tetrahedra,  a cornercorner with one Si(1)AlSi3 tetrahedra,  a cornercorner with one Si(17)AlSi3 tetrahedra,  a cornercorner with one Si(24)AlSi3 tetrahedra,  a cornercorner with one Si(35)AlSi3 tetrahedra,  a cornercorner with one Si(37)AlSi3 tetrahedra,  a cornercorner with one Si(11)Si4 tetrahedra,  a cornercorner with one Si(13)Si4 tetrahedra, and  a cornercorner with one Si(6)Si4 tetrahedra. In the twenty-third Si site, Si(23) is bonded to one Si(14), one Si(2), one Si(24), and one Si(4) atom to form SiSi4 tetrahedra that share  a cornercorner with one Al(2)Si4 tetrahedra,  a cornercorner with one Al(4)Si4 tetrahedra,  a cornercorner with one Al(5)Si4 tetrahedra,  a cornercorner with one Al(8)Si4 tetrahedra,  a cornercorner with one Si(20)Al2Si2 tetrahedra,  a cornercorner with one Si(28)Al2Si2 tetrahedra,  a cornercorner with one Si(26)AlSi3 tetrahedra,  a cornercorner with one Si(9)AlSi3 tetrahedra,  a cornercorner with one Si(13)Si4 tetrahedra,  a cornercorner with one Si(18)Si4 tetrahedra,  a cornercorner with one Si(32)Si4 tetrahedra, and  a cornercorner with one Si(7)Si4 tetrahedra. In the twenty-fourth Si site, Si(24) is bonded to one Al(2), one Si(13), one Si(23), and one Si(7) atom to form distorted SiAlSi3 tetrahedra that share  a cornercorner with one Si(2)Al2Si2 tetrahedra,  a cornercorner with one Si(25)Al2Si2 tetrahedra,  a cornercorner with one Si(28)Al2Si2 tetrahedra,  a cornercorner with one Si(34)Al2Si2 tetrahedra,  a cornercorner with one Si(22)AlSi3 tetrahedra,  a cornercorner with one Si(26)AlSi3 tetrahedra,  a cornercorner with one Si(33)AlSi3 tetrahedra,  a cornercorner with one Si(4)AlSi3 tetrahedra,  a cornercorner with one Si(11)Si4 tetrahedra,  a cornercorner with one Si(14)Si4 tetrahedra,  a cornercorner with one Si(16)Si4 tetrahedra, and  a cornercorner with one Si(21)Si4 tetrahedra. In the twenty-fifth Si site, Si(25) is bonded to one Al(2), one Al(5), one Si(12), and one Si(6) atom to form SiAl2Si2 tetrahedra that share  a cornercorner with one Al(6)Si4 tetrahedra,  a cornercorner with one Si(15)Al2Si2 tetrahedra,  a cornercorner with one Si(2)Al2Si2 tetrahedra,  a cornercorner with one Si(34)Al2Si2 tetrahedra,  a cornercorner with one Si(5)Al2Si2 tetrahedra,  a cornercorner with one Si(10)AlSi3 tetrahedra,  a cornercorner with one Si(17)AlSi3 tetrahedra,  a cornercorner with one Si(22)AlSi3 tetrahedra,  a cornercorner with one Si(24)AlSi3 tetrahedra,  a cornercorner with one Si(33)AlSi3 tetrahedra,  a cornercorner with one Si(21)Si4 tetrahedra, and  a cornercorner with one Si(27)Si4 tetrahedra. In the twenty-sixth Si site, Si(26) is bonded to one Al(3), one Si(13), one Si(27), and one Si(4) atom to form distorted SiAlSi3 tetrahedra that share  a cornercorner with one Al(4)Si4 tetrahedra,  a cornercorner with one Si(15)Al2Si2 tetrahedra,  a cornercorner with one Si(28)Al2Si2 tetrahedra,  a cornercorner with one Si(3)Al2Si2 tetrahedra,  a cornercorner with one Si(31)Al2Si2 tetrahedra,  a cornercorner with one Si(24)AlSi3 tetrahedra,  a cornercorner with one Si(30)AlSi3 tetrahedra,  a cornercorner with one Si(9)AlSi3 tetrahedra,  a cornercorner with one Si(16)Si4 tetrahedra,  a cornercorner with one Si(21)Si4 tetrahedra,  a cornercorner with one Si(23)Si4 tetrahedra, and  a cornercorner with one Si(6)Si4 tetrahedra. In the twenty-seventh Si site, Si(27) is bonded to one Si(15), one Si(26), one Si(3), and one Si(6) atom to form SiSi4 tetrahedra that share  a cornercorner with one Al(3)Si4 tetrahedra,  a cornercorner with one Al(4)Si4 tetrahedra,  a cornercorner with one Al(5)Si4 tetrahedra,  a cornercorner with one Al(6)Si4 tetrahedra,  a cornercorner with one Al(7)Si4 tetrahedra,  a cornercorner with one Si(25)Al2Si2 tetrahedra,  a cornercorner with one Si(10)AlSi3 tetrahedra,  a cornercorner with one Si(19)AlSi3 tetrahedra,  a cornercorner with one Si(4)AlSi3 tetrahedra,  a cornercorner with one Si(13)Si4 tetrahedra,  a cornercorner with one Si(21)Si4 tetrahedra, and  a cornercorner with one Si(29)Si4 tetrahedra. In the twenty-eighth Si site, Si(28) is bonded to one Al(3), one Al(6), one Si(14), and one Si(7) atom to form SiAl2Si2 tetrahedra that share  a cornercorner with one Si(20)Al2Si2 tetrahedra,  a cornercorner with one Si(3)Al2Si2 tetrahedra,  a cornercorner with one Si(31)Al2Si2 tetrahedra,  a cornercorner with one Si(5)Al2Si2 tetrahedra,  a cornercorner with one Si(12)AlSi3 tetrahedra,  a cornercorner with one Si(22)AlSi3 tetrahedra,  a cornercorner with one Si(24)AlSi3 tetrahedra,  a cornercorner with one Si(26)AlSi3 tetrahedra,  a cornercorner with one Si(30)AlSi3 tetrahedra,  a cornercorner with one Si(11)Si4 tetrahedra,  a cornercorner with one Si(18)Si4 tetrahedra, and  a cornercorner with one Si(23)Si4 tetrahedra. In the twenty-ninth Si site, Si(29) is bonded to one Si(19), one Si(3), one Si(30), and one Si(8) atom to form SiSi4 tetrahedra that share  a cornercorner with one Al(3)Si4 tetrahedra,  a cornercorner with one Al(6)Si4 tetrahedra,  a cornercorner with one Al(7)Si4 tetrahedra,  a cornercorner with one Al(8)Si4 tetrahedra,  a cornercorner with one Si(15)Al2Si2 tetrahedra,  a cornercorner with one Si(5)Al2Si2 tetrahedra,  a cornercorner with one Si(35)AlSi3 tetrahedra,  a cornercorner with one Si(9)AlSi3 tetrahedra,  a cornercorner with one Si(18)Si4 tetrahedra,  a cornercorner with one Si(27)Si4 tetrahedra,  a cornercorner with one Si(32)Si4 tetrahedra, and  a cornercorner with one Si(36)Si4 tetrahedra. In the thirtieth Si site, Si(30) is bonded to one Al(3), one Si(18), one Si(29), and one Si(9) atom to form distorted SiAlSi3 tetrahedra that share  a cornercorner with one Al(8)Si4 tetrahedra,  a cornercorner with one Si(28)Al2Si2 tetrahedra,  a cornercorner with one Si(3)Al2Si2 tetrahedra,  a cornercorner with one Si(31)Al2Si2 tetrahedra,  a cornercorner with one Si(19)AlSi3 tetrahedra,  a cornercorner with one Si(26)AlSi3 tetrahedra,  a cornercorner with one Si(37)AlSi3 tetrahedra,  a cornercorner with one Si(4)AlSi3 tetrahedra,  a cornercorner with one Si(14)Si4 tetrahedra,  a cornercorner with one Si(32)Si4 tetrahedra,  a cornercorner with one Si(38)Si4 tetrahedra, and  a cornercorner with one Si(8)Si4 tetrahedra. In the thirty-first Si site, Si(31) is bonded to one Al(3), one Al(7), one Si(11), and one Si(16) atom to form SiAl2Si2 tetrahedra that share  a cornercorner with one Si(28)Al2Si2 tetrahedra,  a cornercorner with one Si(3)Al2Si2 tetrahedra,  a cornercorner with one Si(34)Al2Si2 tetrahedra,  a cornercorner with one Si(10)AlSi3 tetrahedra,  a cornercorner with one Si(17)AlSi3 tetrahedra,  a cornercorner with one Si(26)AlSi3 tetrahedra,  a cornercorner with one Si(30)AlSi3 tetrahedra,  a cornercorner with one Si(33)AlSi3 tetrahedra,  a cornercorner with one Si(37)AlSi3 tetrahedra,  a cornercorner with one Si(13)Si4 tetrahedra,  a cornercorner with one Si(38)Si4 tetrahedra, and  a cornercorner with one Si(7)Si4 tetrahedra. In the thirty-second Si site, Si(32) is bonded to one Si(18), one Si(2), one Si(33), and one Si(8) atom to form SiSi4 tetrahedra that share  a cornercorner with one Al(2)Si4 tetrahedra,  a cornercorner with one Al(5)Si4 tetrahedra,  a cornercorner with one Al(8)Si4 tetrahedra,  a cornercorner with one Si(5)Al2Si2 tetrahedra,  a cornercorner with one Si(17)AlSi3 tetrahedra,  a cornercorner with one Si(30)AlSi3 tetrahedra,  a cornercorner with one Si(35)AlSi3 tetrahedra,  a cornercorner with one Si(37)AlSi3 tetrahedra,  a cornercorner with one Si(11)Si4 tetrahedra,  a cornercorner with one Si(14)Si4 tetrahedra,  a cornercorner with one Si(23)Si4 tetrahedra, and  a cornercorner with one Si(29)Si4 tetrahedra. In the thirty-third Si site, Si(33) is bonded to one Al(2), one Si(11), one Si(17), and one Si(32) atom to form distorted SiAlSi3 tetrahedra that share  a cornercorner with one Al(7)Si4 tetrahedra,  a cornercorner with one Si(2)Al2Si2 tetrahedra,  a cornercorner with one Si(25)Al2Si2 tetrahedra,  a cornercorner with one Si(31)Al2Si2 tetrahedra,  a cornercorner with one Si(34)Al2Si2 tetrahedra,  a cornercorner with one Si(12)AlSi3 tetrahedra,  a cornercorner with one Si(24)AlSi3 tetrahedra,  a cornercorner with one Si(35)AlSi3 tetrahedra,  a cornercorner with one Si(37)AlSi3 tetrahedra,  a cornercorner with one Si(18)Si4 tetrahedra,  a cornercorner with one Si(7)Si4 tetrahedra, and  a cornercorner with one Si(8)Si4 tetrahedra. In the thirty-fourth Si site, Si(34) is bonded to one Al(2), one Al(8), one Si(10), and one Si(16) atom to form SiAl2Si2 tetrahedra that share  a cornercorner with one Al(7)Si4 tetrahedra,  a cornercorner with one Si(2)Al2Si2 tetrahedra,  a cornercorner with one Si(25)Al2Si2 tetrahedra,  a cornercorner with one Si(31)Al2Si2 tetrahedra,  a cornercorner with one Si(19)AlSi3 tetrahedra,  a cornercorner with one Si(24)AlSi3 tetrahedra,  a cornercorner with one Si(33)AlSi3 tetrahedra,  a cornercorner with one Si(9)AlSi3 tetrahedra,  a cornercorner with one Si(13)Si4 tetrahedra,  a cornercorner with one Si(36)Si4 tetrahedra,  a cornercorner with one Si(38)Si4 tetrahedra, and  a cornercorner with one Si(6)Si4 tetrahedra. In the thirty-fifth Si site, Si(35) is bonded to one Al(1), one Si(17), one Si(36), and one Si(8) atom to form distorted SiAlSi3 tetrahedra that share  a cornercorner with one Al(7)Si4 tetrahedra,  a cornercorner with one Si(20)Al2Si2 tetrahedra,  a cornercorner with one Si(5)Al2Si2 tetrahedra,  a cornercorner with one Si(1)AlSi3 tetrahedra,  a cornercorner with one Si(10)AlSi3 tetrahedra,  a cornercorner with one Si(12)AlSi3 tetrahedra,  a cornercorner with one Si(19)AlSi3 tetrahedra,  a cornercorner with one Si(22)AlSi3 tetrahedra,  a cornercorner with one Si(33)AlSi3 tetrahedra,  a cornercorner with one Si(37)AlSi3 tetrahedra,  a cornercorner with one Si(29)Si4 tetrahedra, and  a cornercorner with one Si(32)Si4 tetrahedra. In the thirty-sixth Si site, Si(36) is bonded to one Si(1), one Si(10), one Si(19), and one Si(35) atom to form SiSi4 tetrahedra that share  a cornercorner with one Al(1)Si4 tetrahedra,  a cornercorner with one Al(4)Si4 tetrahedra,  a cornercorner with one Al(7)Si4 tetrahedra,  a cornercorner with one Al(8)Si4 tetrahedra,  a cornercorner with one Si(15)Al2Si2 tetrahedra,  a cornercorner with one Si(34)Al2Si2 tetrahedra,  a cornercorner with one Si(17)AlSi3 tetrahedra,  a cornercorner with one Si(21)Si4 tetrahedra,  a cornercorner with one Si(29)Si4 tetrahedra,  a cornercorner with one Si(38)Si4 tetrahedra,  a cornercorner with one Si(6)Si4 tetrahedra, and  a cornercorner with one Si(8)Si4 tetrahedra. In the thirty-seventh Si site, Si(37) is bonded to one Al(1), one Si(11), one Si(18), and one Si(38) atom to form SiAlSi3 tetrahedra that share  a cornercorner with one Si(20)Al2Si2 tetrahedra,  a cornercorner with one Si(31)Al2Si2 tetrahedra,  a cornercorner with one Si(1)AlSi3 tetrahedra,  a cornercorner with one Si(22)AlSi3 tetrahedra,  a cornercorner with one Si(30)AlSi3 tetrahedra,  a cornercorner with one Si(33)AlSi3 tetrahedra,  a cornercorner with one Si(35)AlSi3 tetrahedra,  a cornercorner with one Si(9)AlSi3 tetrahedra,  a cornercorner with one Si(14)Si4 tetrahedra,  a cornercorner with one Si(16)Si4 tetrahedra,  a cornercorner with one Si(32)Si4 tetrahedra, and  a cornercorner with one Si(7)Si4 tetrahedra. In the thirty-eighth Si site, Si(38) is bonded to one Si(1), one Si(16), one Si(37), and one Si(9) atom to form SiSi4 tetrahedra that share  a cornercorner with one Al(1)Si4 tetrahedra,  a cornercorner with one Al(4)Si4 tetrahedra,  a cornercorner with one Al(8)Si4 tetrahedra,  a cornercorner with one Si(31)Al2Si2 tetrahedra,  a cornercorner with one Si(34)Al2Si2 tetrahedra,  a cornercorner with one Si(30)AlSi3 tetrahedra,  a cornercorner with one Si(4)AlSi3 tetrahedra,  a cornercorner with one Si(11)Si4 tetrahedra,  a cornercorner with one Si(13)Si4 tetrahedra,  a cornercorner with one Si(18)Si4 tetrahedra,  a cornercorner with one Si(21)Si4 tetrahedra, and  a cornercorner with one Si(36)Si4 tetrahedra.
Al4Si19 is beta beryllia-like structured and crystallizes in the triclinic P1 space group. There are eight inequivalent Al sites. In the first Al site, Al(1) is bonded to one Si(20), one Si(22), one Si(35), and one Si(37) atom to form AlSi4 tetrahedra that share  a cornercorner with one Al(4)Si4 tetrahedra,  a cornercorner with one Si(5)Al2Si2 tetrahedra,  a cornercorner with one Si(12)AlSi3 tetrahedra,  a cornercorner with one Si(17)AlSi3 tetrahedra,  a cornercorner with one Si(11)Si4 tetrahedra,  a cornercorner with one Si(14)Si4 tetrahedra,  a cornercorner with one Si(18)Si4 tetrahedra,  a cornercorner with one Si(21)Si4 tetrahedra,  a cornercorner with one Si(36)Si4 tetrahedra,  a cornercorner with one Si(38)Si4 tetrahedra,  a cornercorner with one Si(7)Si4 tetrahedra, and  a cornercorner with one Si(8)Si4 tetrahedra. The Al(1)-Si(20) bond length is 2.49 Å. The Al(1)-Si(22) bond length is 2.51 Å. The Al(1)-Si(35) bond length is 2.49 Å. The Al(1)-Si(37) bond length is 2.48 Å. In the second Al site, Al(2) is bonded to one Si(24), one Si(25), one Si(33), and one Si(34) atom to form AlSi4 tetrahedra that share  a cornercorner with one Al(5)Si4 tetrahedra,  a cornercorner with one Al(8)Si4 tetrahedra,  a cornercorner with one Si(10)AlSi3 tetrahedra,  a cornercorner with one Si(12)AlSi3 tetrahedra,  a cornercorner with one Si(17)AlSi3 tetrahedra,  a cornercorner with one Si(11)Si4 tetrahedra,  a cornercorner with one Si(13)Si4 tetrahedra,  a cornercorner with one Si(16)Si4 tetrahedra,  a cornercorner with one Si(23)Si4 tetrahedra,  a cornercorner with one Si(32)Si4 tetrahedra,  a cornercorner with one Si(6)Si4 tetrahedra, and  a cornercorner with one Si(7)Si4 tetrahedra. The Al(2)-Si(24) bond length is 2.46 Å. The Al(2)-Si(25) bond length is 2.54 Å. The Al(2)-Si(33) bond length is 2.50 Å. The Al(2)-Si(34) bond length is 2.49 Å. In the third Al site, Al(3) is bonded to one Si(26), one Si(28), one Si(30), and one Si(31) atom to form AlSi4 tetrahedra that share  a cornercorner with one Al(6)Si4 tetrahedra,  a cornercorner with one Al(7)Si4 tetrahedra,  a cornercorner with one Si(4)AlSi3 tetrahedra,  a cornercorner with one Si(9)AlSi3 tetrahedra,  a cornercorner with one Si(11)Si4 tetrahedra,  a cornercorner with one Si(13)Si4 tetrahedra,  a cornercorner with one Si(14)Si4 tetrahedra,  a cornercorner with one Si(16)Si4 tetrahedra,  a cornercorner with one Si(18)Si4 tetrahedra,  a cornercorner with one Si(27)Si4 tetrahedra,  a cornercorner with one Si(29)Si4 tetrahedra, and  a cornercorner with one Si(7)Si4 tetrahedra. The Al(3)-Si(26) bond length is 2.49 Å. The Al(3)-Si(28) bond length is 2.50 Å. The Al(3)-Si(30) bond length is 2.51 Å. The Al(3)-Si(31) bond length is 2.51 Å. In the fourth Al site, Al(4) is bonded to one Si(1), one Si(15), one Si(20), and one Si(4) atom to form AlSi4 tetrahedra that share  a cornercorner with one Al(1)Si4 tetrahedra,  a cornercorner with one Al(5)Si4 tetrahedra,  a cornercorner with one Si(5)Al2Si2 tetrahedra,  a cornercorner with one Si(19)AlSi3 tetrahedra,  a cornercorner with one Si(26)AlSi3 tetrahedra,  a cornercorner with one Si(9)AlSi3 tetrahedra,  a cornercorner with one Si(14)Si4 tetrahedra,  a cornercorner with one Si(21)Si4 tetrahedra,  a cornercorner with one Si(23)Si4 tetrahedra,  a cornercorner with one Si(27)Si4 tetrahedra,  a cornercorner with one Si(36)Si4 tetrahedra, and  a cornercorner with one Si(38)Si4 tetrahedra. The Al(4)-Si(1) bond length is 2.49 Å. The Al(4)-Si(15) bond length is 2.49 Å. The Al(4)-Si(20) bond length is 2.46 Å. The Al(4)-Si(4) bond length is 2.52 Å. In the fifth Al site, Al(5) is bonded to one Si(15), one Si(2), one Si(25), and one Si(5) atom to form AlSi4 tetrahedra that share  a cornercorner with one Al(2)Si4 tetrahedra,  a cornercorner with one Al(4)Si4 tetrahedra,  a cornercorner with one Al(6)Si4 tetrahedra,  a cornercorner with one Al(8)Si4 tetrahedra,  a cornercorner with one Si(20)Al2Si2 tetrahedra,  a cornercorner with one Si(12)AlSi3 tetrahedra,  a cornercorner with one Si(19)AlSi3 tetrahedra,  a cornercorner with one Si(23)Si4 tetrahedra,  a cornercorner with one Si(27)Si4 tetrahedra,  a cornercorner with one Si(32)Si4 tetrahedra,  a cornercorner with one Si(6)Si4 tetrahedra, and  a cornercorner with one Si(8)Si4 tetrahedra. The Al(5)-Si(15) bond length is 2.50 Å. The Al(5)-Si(2) bond length is 2.49 Å. The Al(5)-Si(25) bond length is 2.51 Å. The Al(5)-Si(5) bond length is 2.56 Å. In the sixth Al site, Al(6) is bonded to one Si(12), one Si(28), one Si(3), and one Si(5) atom to form AlSi4 tetrahedra that share  a cornercorner with one Al(3)Si4 tetrahedra,  a cornercorner with one Al(5)Si4 tetrahedra,  a cornercorner with one Al(7)Si4 tetrahedra,  a cornercorner with one Si(20)Al2Si2 tetrahedra,  a cornercorner with one Si(25)Al2Si2 tetrahedra,  a cornercorner with one Si(17)AlSi3 tetrahedra,  a cornercorner with one Si(22)AlSi3 tetrahedra,  a cornercorner with one Si(14)Si4 tetrahedra,  a cornercorner with one Si(27)Si4 tetrahedra,  a cornercorner with one Si(29)Si4 tetrahedra,  a cornercorner with one Si(7)Si4 tetrahedra, and  a cornercorner with one Si(8)Si4 tetrahedra. The Al(6)-Si(12) bond length is 2.57 Å. The Al(6)-Si(28) bond length is 2.47 Å. The Al(6)-Si(3) bond length is 2.50 Å. The Al(6)-Si(5) bond length is 2.55 Å. In the seventh Al site, Al(7) is bonded to one Si(10), one Si(17), one Si(3), and one Si(31) atom to form AlSi4 tetrahedra that share  a cornercorner with one Al(3)Si4 tetrahedra,  a cornercorner with one Al(6)Si4 tetrahedra,  a cornercorner with one Si(34)Al2Si2 tetrahedra,  a cornercorner with one Si(12)AlSi3 tetrahedra,  a cornercorner with one Si(33)AlSi3 tetrahedra,  a cornercorner with one Si(35)AlSi3 tetrahedra,  a cornercorner with one Si(11)Si4 tetrahedra,  a cornercorner with one Si(16)Si4 tetrahedra,  a cornercorner with one Si(27)Si4 tetrahedra,  a cornercorner with one Si(29)Si4 tetrahedra,  a cornercorner with one Si(36)Si4 tetrahedra, and  a cornercorner with one Si(6)Si4 tetrahedra. The Al(7)-Si(10) bond length is 2.53 Å. The Al(7)-Si(17) bond length is 2.53 Å. The Al(7)-Si(3) bond length is 2.48 Å. The Al(7)-Si(31) bond length is 2.44 Å. In the eighth Al site, Al(8) is bonded to one Si(19), one Si(2), one Si(34), and one Si(9) atom to form AlSi4 tetrahedra that share  a cornercorner with one Al(2)Si4 tetrahedra,  a cornercorner with one Al(5)Si4 tetrahedra,  a cornercorner with one Si(15)Al2Si2 tetrahedra,  a cornercorner with one Si(10)AlSi3 tetrahedra,  a cornercorner with one Si(30)AlSi3 tetrahedra,  a cornercorner with one Si(4)AlSi3 tetrahedra,  a cornercorner with one Si(16)Si4 tetrahedra,  a cornercorner with one Si(23)Si4 tetrahedra,  a cornercorner with one Si(29)Si4 tetrahedra,  a cornercorner with one Si(32)Si4 tetrahedra,  a cornercorner with one Si(36)Si4 tetrahedra, and  a cornercorner with one Si(38)Si4 tetrahedra. The Al(8)-Si(19) bond length is 2.49 Å. The Al(8)-Si(2) bond length is 2.49 Å. The Al(8)-Si(34) bond length is 2.49 Å. The Al(8)-Si(9) bond length is 2.52 Å. There are thirty-eight inequivalent Si sites. In the first Si site, Si(1) is bonded to one Al(4), one Si(21), one Si(36), and one Si(38) atom to form SiAlSi3 tetrahedra that share  a cornercorner with one Si(15)Al2Si2 tetrahedra,  a cornercorner with one Si(20)Al2Si2 tetrahedra,  a cornercorner with one Si(10)AlSi3 tetrahedra,  a cornercorner with one Si(19)AlSi3 tetrahedra,  a cornercorner with one Si(22)AlSi3 tetrahedra,  a cornercorner with one Si(35)AlSi3 tetrahedra,  a cornercorner with one Si(37)AlSi3 tetrahedra,  a cornercorner with one Si(4)AlSi3 tetrahedra,  a cornercorner with one Si(9)AlSi3 tetrahedra,  a cornercorner with one Si(13)Si4 tetrahedra,  a cornercorner with one Si(16)Si4 tetrahedra, and  a cornercorner with one Si(6)Si4 tetrahedra. The Si(1)-Si(21) bond length is 2.38 Å. The Si(1)-Si(36) bond length is 2.37 Å. The Si(1)-Si(38) bond length is 2.38 Å. In the second Si site, Si(2) is bonded to one Al(5), one Al(8), one Si(23), and one Si(32) atom to form SiAl2Si2 tetrahedra that share  a cornercorner with one Si(15)Al2Si2 tetrahedra,  a cornercorner with one Si(25)Al2Si2 tetrahedra,  a cornercorner with one Si(34)Al2Si2 tetrahedra,  a cornercorner with one Si(5)Al2Si2 tetrahedra,  a cornercorner with one Si(19)AlSi3 tetrahedra,  a cornercorner with one Si(24)AlSi3 tetrahedra,  a cornercorner with one Si(33)AlSi3 tetrahedra,  a cornercorner with one Si(4)AlSi3 tetrahedra,  a cornercorner with one Si(9)AlSi3 tetrahedra,  a cornercorner with one Si(14)Si4 tetrahedra,  a cornercorner with one Si(18)Si4 tetrahedra, and  a cornercorner with one Si(8)Si4 tetrahedra. The Si(2)-Si(23) bond length is 2.37 Å. The Si(2)-Si(32) bond length is 2.37 Å. In the third Si site, Si(3) is bonded to one Al(6), one Al(7), one Si(27), and one Si(29) atom to form SiAl2Si2 tetrahedra that share  a cornercorner with one Si(15)Al2Si2 tetrahedra,  a cornercorner with one Si(28)Al2Si2 tetrahedra,  a cornercorner with one Si(31)Al2Si2 tetrahedra,  a cornercorner with one Si(5)Al2Si2 tetrahedra,  a cornercorner with one Si(10)AlSi3 tetrahedra,  a cornercorner with one Si(12)AlSi3 tetrahedra,  a cornercorner with one Si(17)AlSi3 tetrahedra,  a cornercorner with one Si(19)AlSi3 tetrahedra,  a cornercorner with one Si(26)AlSi3 tetrahedra,  a cornercorner with one Si(30)AlSi3 tetrahedra,  a cornercorner with one Si(6)Si4 tetrahedra, and  a cornercorner with one Si(8)Si4 tetrahedra. The Si(3)-Si(27) bond length is 2.39 Å. The Si(3)-Si(29) bond length is 2.40 Å. In the fourth Si site, Si(4) is bonded to one Al(4), one Si(23), one Si(26), and one Si(9) atom to form SiAlSi3 tetrahedra that share  a cornercorner with one Al(3)Si4 tetrahedra,  a cornercorner with one Al(8)Si4 tetrahedra,  a cornercorner with one Si(15)Al2Si2 tetrahedra,  a cornercorner with one Si(2)Al2Si2 tetrahedra,  a cornercorner with one Si(20)Al2Si2 tetrahedra,  a cornercorner with one Si(1)AlSi3 tetrahedra,  a cornercorner with one Si(24)AlSi3 tetrahedra,  a cornercorner with one Si(30)AlSi3 tetrahedra,  a cornercorner with one Si(13)Si4 tetrahedra,  a cornercorner with one Si(14)Si4 tetrahedra,  a cornercorner with one Si(27)Si4 tetrahedra, and  a cornercorner with one Si(38)Si4 tetrahedra. The Si(4)-Si(23) bond length is 2.37 Å. The Si(4)-Si(26) bond length is 2.35 Å. The Si(4)-Si(9) bond length is 2.37 Å. In the fifth Si site, Si(5) is bonded to one Al(5), one Al(6), one Si(20), and one Si(8) atom to form SiAl2Si2 tetrahedra that share  a cornercorner with one Al(1)Si4 tetrahedra,  a cornercorner with one Al(4)Si4 tetrahedra,  a cornercorner with one Si(15)Al2Si2 tetrahedra,  a cornercorner with one Si(2)Al2Si2 tetrahedra,  a cornercorner with one Si(25)Al2Si2 tetrahedra,  a cornercorner with one Si(28)Al2Si2 tetrahedra,  a cornercorner with one Si(3)Al2Si2 tetrahedra,  a cornercorner with one Si(12)AlSi3 tetrahedra,  a cornercorner with one Si(35)AlSi3 tetrahedra,  a cornercorner with one Si(14)Si4 tetrahedra,  a cornercorner with one Si(29)Si4 tetrahedra, and  a cornercorner with one Si(32)Si4 tetrahedra. The Si(5)-Si(20) bond length is 2.35 Å. The Si(5)-Si(8) bond length is 2.37 Å. In the sixth Si site, Si(6) is bonded to one Si(10), one Si(21), one Si(25), and one Si(27) atom to form SiSi4 tetrahedra that share  a cornercorner with one Al(2)Si4 tetrahedra,  a cornercorner with one Al(5)Si4 tetrahedra,  a cornercorner with one Al(7)Si4 tetrahedra,  a cornercorner with one Si(15)Al2Si2 tetrahedra,  a cornercorner with one Si(3)Al2Si2 tetrahedra,  a cornercorner with one Si(34)Al2Si2 tetrahedra,  a cornercorner with one Si(1)AlSi3 tetrahedra,  a cornercorner with one Si(12)AlSi3 tetrahedra,  a cornercorner with one Si(22)AlSi3 tetrahedra,  a cornercorner with one Si(26)AlSi3 tetrahedra,  a cornercorner with one Si(13)Si4 tetrahedra, and  a cornercorner with one Si(36)Si4 tetrahedra. The Si(6)-Si(10) bond length is 2.36 Å. The Si(6)-Si(21) bond length is 2.37 Å. The Si(6)-Si(25) bond length is 2.35 Å. The Si(6)-Si(27) bond length is 2.38 Å. In the seventh Si site, Si(7) is bonded to one Si(11), one Si(22), one Si(24), and one Si(28) atom to form SiSi4 tetrahedra that share  a cornercorner with one Al(1)Si4 tetrahedra,  a cornercorner with one Al(2)Si4 tetrahedra,  a cornercorner with one Al(3)Si4 tetrahedra,  a cornercorner with one Al(6)Si4 tetrahedra,  a cornercorner with one Si(31)Al2Si2 tetrahedra,  a cornercorner with one Si(12)AlSi3 tetrahedra,  a cornercorner with one Si(33)AlSi3 tetrahedra,  a cornercorner with one Si(37)AlSi3 tetrahedra,  a cornercorner with one Si(13)Si4 tetrahedra,  a cornercorner with one Si(14)Si4 tetrahedra,  a cornercorner with one Si(21)Si4 tetrahedra, and  a cornercorner with one Si(23)Si4 tetrahedra. The Si(7)-Si(11) bond length is 2.40 Å. The Si(7)-Si(22) bond length is 2.39 Å. The Si(7)-Si(24) bond length is 2.37 Å. The Si(7)-Si(28) bond length is 2.36 Å. In the eighth Si site, Si(8) is bonded to one Si(29), one Si(32), one Si(35), and one Si(5) atom to form SiSi4 tetrahedra that share  a cornercorner with one Al(1)Si4 tetrahedra,  a cornercorner with one Al(5)Si4 tetrahedra,  a cornercorner with one Al(6)Si4 tetrahedra,  a cornercorner with one Si(2)Al2Si2 tetrahedra,  a cornercorner with one Si(20)Al2Si2 tetrahedra,  a cornercorner with one Si(3)Al2Si2 tetrahedra,  a cornercorner with one Si(17)AlSi3 tetrahedra,  a cornercorner with one Si(19)AlSi3 tetrahedra,  a cornercorner with one Si(30)AlSi3 tetrahedra,  a cornercorner with one Si(33)AlSi3 tetrahedra,  a cornercorner with one Si(18)Si4 tetrahedra, and  a cornercorner with one Si(36)Si4 tetrahedra. The Si(8)-Si(29) bond length is 2.37 Å. The Si(8)-Si(32) bond length is 2.39 Å. The Si(8)-Si(35) bond length is 2.36 Å. In the ninth Si site, Si(9) is bonded to one Al(8), one Si(30), one Si(38), and one Si(4) atom to form SiAlSi3 tetrahedra that share  a cornercorner with one Al(3)Si4 tetrahedra,  a cornercorner with one Al(4)Si4 tetrahedra,  a cornercorner with one Si(2)Al2Si2 tetrahedra,  a cornercorner with one Si(34)Al2Si2 tetrahedra,  a cornercorner with one Si(1)AlSi3 tetrahedra,  a cornercorner with one Si(19)AlSi3 tetrahedra,  a cornercorner with one Si(26)AlSi3 tetrahedra,  a cornercorner with one Si(37)AlSi3 tetrahedra,  a cornercorner with one Si(16)Si4 tetrahedra,  a cornercorner with one Si(18)Si4 tetrahedra,  a cornercorner with one Si(23)Si4 tetrahedra, and  a cornercorner with one Si(29)Si4 tetrahedra. The Si(9)-Si(30) bond length is 2.37 Å. The Si(9)-Si(38) bond length is 2.37 Å. In the tenth Si site, Si(10) is bonded to one Al(7), one Si(34), one Si(36), and one Si(6) atom to form SiAlSi3 tetrahedra that share  a cornercorner with one Al(2)Si4 tetrahedra,  a cornercorner with one Al(8)Si4 tetrahedra,  a cornercorner with one Si(25)Al2Si2 tetrahedra,  a cornercorner with one Si(3)Al2Si2 tetrahedra,  a cornercorner with one Si(31)Al2Si2 tetrahedra,  a cornercorner with one Si(1)AlSi3 tetrahedra,  a cornercorner with one Si(17)AlSi3 tetrahedra,  a cornercorner with one Si(19)AlSi3 tetrahedra,  a cornercorner with one Si(35)AlSi3 tetrahedra,  a cornercorner with one Si(16)Si4 tetrahedra,  a cornercorner with one Si(21)Si4 tetrahedra, and  a cornercorner with one Si(27)Si4 tetrahedra. The Si(10)-Si(34) bond length is 2.35 Å. The Si(10)-Si(36) bond length is 2.37 Å. In the eleventh Si site, Si(11) is bonded to one Si(31), one Si(33), one Si(37), and one Si(7) atom to form SiSi4 tetrahedra that share  a cornercorner with one Al(1)Si4 tetrahedra,  a cornercorner with one Al(2)Si4 tetrahedra,  a cornercorner with one Al(3)Si4 tetrahedra,  a cornercorner with one Al(7)Si4 tetrahedra,  a cornercorner with one Si(28)Al2Si2 tetrahedra,  a cornercorner with one Si(17)AlSi3 tetrahedra,  a cornercorner with one Si(22)AlSi3 tetrahedra,  a cornercorner with one Si(24)AlSi3 tetrahedra,  a cornercorner with one Si(16)Si4 tetrahedra,  a cornercorner with one Si(18)Si4 tetrahedra,  a cornercorner with one Si(32)Si4 tetrahedra, and  a cornercorner with one Si(38)Si4 tetrahedra. The Si(11)-Si(31) bond length is 2.36 Å. The Si(11)-Si(33) bond length is 2.40 Å. The Si(11)-Si(37) bond length is 2.38 Å. In the twelfth Si site, Si(12) is bonded to one Al(6), one Si(17), one Si(22), and one Si(25) atom to form SiAlSi3 tetrahedra that share  a cornercorner with one Al(1)Si4 tetrahedra,  a cornercorner with one Al(2)Si4 tetrahedra,  a cornercorner with one Al(5)Si4 tetrahedra,  a cornercorner with one Al(7)Si4 tetrahedra,  a cornercorner with one Si(28)Al2Si2 tetrahedra,  a cornercorner with one Si(3)Al2Si2 tetrahedra,  a cornercorner with one Si(5)Al2Si2 tetrahedra,  a cornercorner with one Si(33)AlSi3 tetrahedra,  a cornercorner with one Si(35)AlSi3 tetrahedra,  a cornercorner with one Si(21)Si4 tetrahedra,  a cornercorner with one Si(6)Si4 tetrahedra, and  a cornercorner with one Si(7)Si4 tetrahedra. The Si(12)-Si(17) bond length is 2.39 Å. The Si(12)-Si(22) bond length is 2.38 Å. The Si(12)-Si(25) bond length is 2.33 Å. In the thirteenth Si site, Si(13) is bonded to one Si(16), one Si(21), one Si(24), and one Si(26) atom to form SiSi4 tetrahedra that share  a cornercorner with one Al(2)Si4 tetrahedra,  a cornercorner with one Al(3)Si4 tetrahedra,  a cornercorner with one Si(31)Al2Si2 tetrahedra,  a cornercorner with one Si(34)Al2Si2 tetrahedra,  a cornercorner with one Si(1)AlSi3 tetrahedra,  a cornercorner with one Si(22)AlSi3 tetrahedra,  a cornercorner with one Si(4)AlSi3 tetrahedra,  a cornercorner with one Si(23)Si4 tetrahedra,  a cornercorner with one Si(27)Si4 tetrahedra,  a cornercorner with one Si(38)Si4 tetrahedra,  a cornercorner with one Si(6)Si4 tetrahedra, and  a cornercorner with one Si(7)Si4 tetrahedra. The Si(13)-Si(16) bond length is 2.40 Å. The Si(13)-Si(21) bond length is 2.37 Å. The Si(13)-Si(24) bond length is 2.37 Å. The Si(13)-Si(26) bond length is 2.36 Å. In the fourteenth Si site, Si(14) is bonded to one Si(18), one Si(20), one Si(23), and one Si(28) atom to form SiSi4 tetrahedra that share  a cornercorner with one Al(1)Si4 tetrahedra,  a cornercorner with one Al(3)Si4 tetrahedra,  a cornercorner with one Al(4)Si4 tetrahedra,  a cornercorner with one Al(6)Si4 tetrahedra,  a cornercorner with one Si(2)Al2Si2 tetrahedra,  a cornercorner with one Si(5)Al2Si2 tetrahedra,  a cornercorner with one Si(24)AlSi3 tetrahedra,  a cornercorner with one Si(30)AlSi3 tetrahedra,  a cornercorner with one Si(37)AlSi3 tetrahedra,  a cornercorner with one Si(4)AlSi3 tetrahedra,  a cornercorner with one Si(32)Si4 tetrahedra, and  a cornercorner with one Si(7)Si4 tetrahedra. The Si(14)-Si(18) bond length is 2.40 Å. The Si(14)-Si(20) bond length is 2.38 Å. The Si(14)-Si(23) bond length is 2.40 Å. The Si(14)-Si(28) bond length is 2.36 Å. In the fifteenth Si site, Si(15) is bonded to one Al(4), one Al(5), one Si(19), and one Si(27) atom to form SiAl2Si2 tetrahedra that share  a cornercorner with one Al(8)Si4 tetrahedra,  a cornercorner with one Si(2)Al2Si2 tetrahedra,  a cornercorner with one Si(20)Al2Si2 tetrahedra,  a cornercorner with one Si(25)Al2Si2 tetrahedra,  a cornercorner with one Si(3)Al2Si2 tetrahedra,  a cornercorner with one Si(5)Al2Si2 tetrahedra,  a cornercorner with one Si(1)AlSi3 tetrahedra,  a cornercorner with one Si(26)AlSi3 tetrahedra,  a cornercorner with one Si(4)AlSi3 tetrahedra,  a cornercorner with one Si(29)Si4 tetrahedra,  a cornercorner with one Si(36)Si4 tetrahedra, and  a cornercorner with one Si(6)Si4 tetrahedra. The Si(15)-Si(19) bond length is 2.33 Å. The Si(15)-Si(27) bond length is 2.34 Å. In the sixteenth Si site, Si(16) is bonded to one Si(13), one Si(31), one Si(34), and one Si(38) atom to form SiSi4 tetrahedra that share  a cornercorner with one Al(2)Si4 tetrahedra,  a cornercorner with one Al(3)Si4 tetrahedra,  a cornercorner with one Al(7)Si4 tetrahedra,  a cornercorner with one Al(8)Si4 tetrahedra,  a cornercorner with one Si(1)AlSi3 tetrahedra,  a cornercorner with one Si(10)AlSi3 tetrahedra,  a cornercorner with one Si(24)AlSi3 tetrahedra,  a cornercorner with one Si(26)AlSi3 tetrahedra,  a cornercorner with one Si(37)AlSi3 tetrahedra,  a cornercorner with one Si(9)AlSi3 tetrahedra,  a cornercorner with one Si(11)Si4 tetrahedra, and  a cornercorner with one Si(21)Si4 tetrahedra. The Si(16)-Si(31) bond length is 2.36 Å. The Si(16)-Si(34) bond length is 2.39 Å. The Si(16)-Si(38) bond length is 2.40 Å. In the seventeenth Si site, Si(17) is bonded to one Al(7), one Si(12), one Si(33), and one Si(35) atom to form SiAlSi3 tetrahedra that share  a cornercorner with one Al(1)Si4 tetrahedra,  a cornercorner with one Al(2)Si4 tetrahedra,  a cornercorner with one Al(6)Si4 tetrahedra,  a cornercorner with one Si(25)Al2Si2 tetrahedra,  a cornercorner with one Si(3)Al2Si2 tetrahedra,  a cornercorner with one Si(31)Al2Si2 tetrahedra,  a cornercorner with one Si(10)AlSi3 tetrahedra,  a cornercorner with one Si(22)AlSi3 tetrahedra,  a cornercorner with one Si(11)Si4 tetrahedra,  a cornercorner with one Si(32)Si4 tetrahedra,  a cornercorner with one Si(36)Si4 tetrahedra, and  a cornercorner with one Si(8)Si4 tetrahedra. The Si(17)-Si(33) bond length is 2.38 Å. The Si(17)-Si(35) bond length is 2.36 Å. In the eighteenth Si site, Si(18) is bonded to one Si(14), one Si(30), one Si(32), and one Si(37) atom to form SiSi4 tetrahedra that share  a cornercorner with one Al(1)Si4 tetrahedra,  a cornercorner with one Al(3)Si4 tetrahedra,  a cornercorner with one Si(2)Al2Si2 tetrahedra,  a cornercorner with one Si(20)Al2Si2 tetrahedra,  a cornercorner with one Si(28)Al2Si2 tetrahedra,  a cornercorner with one Si(33)AlSi3 tetrahedra,  a cornercorner with one Si(9)AlSi3 tetrahedra,  a cornercorner with one Si(11)Si4 tetrahedra,  a cornercorner with one Si(23)Si4 tetrahedra,  a cornercorner with one Si(29)Si4 tetrahedra,  a cornercorner with one Si(38)Si4 tetrahedra, and  a cornercorner with one Si(8)Si4 tetrahedra. The Si(18)-Si(30) bond length is 2.36 Å. The Si(18)-Si(32) bond length is 2.37 Å. The Si(18)-Si(37) bond length is 2.38 Å. In the nineteenth Si site, Si(19) is bonded to one Al(8), one Si(15), one Si(29), and one Si(36) atom to form SiAlSi3 tetrahedra that share  a cornercorner with one Al(4)Si4 tetrahedra,  a cornercorner with one Al(5)Si4 tetrahedra,  a cornercorner with one Si(2)Al2Si2 tetrahedra,  a cornercorner with one Si(3)Al2Si2 tetrahedra,  a cornercorner with one Si(34)Al2Si2 tetrahedra,  a cornercorner with one Si(1)AlSi3 tetrahedra,  a cornercorner with one Si(10)AlSi3 tetrahedra,  a cornercorner with one Si(30)AlSi3 tetrahedra,  a cornercorner with one Si(35)AlSi3 tetrahedra,  a cornercorner with one Si(9)AlSi3 tetrahedra,  a cornercorner with one Si(27)Si4 tetrahedra, and  a cornercorner with one Si(8)Si4 tetrahedra. The Si(19)-Si(29) bond length is 2.34 Å. The Si(19)-Si(36) bond length is 2.38 Å. In the twentieth Si site, Si(20) is bonded to one Al(1), one Al(4), one Si(14), and one Si(5) atom to form SiAl2Si2 tetrahedra that share  a cornercorner with one Al(5)Si4 tetrahedra,  a cornercorner with one Al(6)Si4 tetrahedra,  a cornercorner with one Si(15)Al2Si2 tetrahedra,  a cornercorner with one Si(28)Al2Si2 tetrahedra,  a cornercorner with one Si(1)AlSi3 tetrahedra,  a cornercorner with one Si(22)AlSi3 tetrahedra,  a cornercorner with one Si(35)AlSi3 tetrahedra,  a cornercorner with one Si(37)AlSi3 tetrahedra,  a cornercorner with one Si(4)AlSi3 tetrahedra,  a cornercorner with one Si(18)Si4 tetrahedra,  a cornercorner with one Si(23)Si4 tetrahedra, and  a cornercorner with one Si(8)Si4 tetrahedra. In the twenty-first Si site, Si(21) is bonded to one Si(1), one Si(13), one Si(22), and one Si(6) atom to form SiSi4 tetrahedra that share  a cornercorner with one Al(1)Si4 tetrahedra,  a cornercorner with one Al(4)Si4 tetrahedra,  a cornercorner with one Si(25)Al2Si2 tetrahedra,  a cornercorner with one Si(10)AlSi3 tetrahedra,  a cornercorner with one Si(12)AlSi3 tetrahedra,  a cornercorner with one Si(24)AlSi3 tetrahedra,  a cornercorner with one Si(26)AlSi3 tetrahedra,  a cornercorner with one Si(16)Si4 tetrahedra,  a cornercorner with one Si(27)Si4 tetrahedra,  a cornercorner with one Si(36)Si4 tetrahedra,  a cornercorner with one Si(38)Si4 tetrahedra, and  a cornercorner with one Si(7)Si4 tetrahedra. The Si(21)-Si(22) bond length is 2.36 Å. In the twenty-second Si site, Si(22) is bonded to one Al(1), one Si(12), one Si(21), and one Si(7) atom to form distorted SiAlSi3 tetrahedra that share  a cornercorner with one Al(6)Si4 tetrahedra,  a cornercorner with one Si(20)Al2Si2 tetrahedra,  a cornercorner with one Si(25)Al2Si2 tetrahedra,  a cornercorner with one Si(28)Al2Si2 tetrahedra,  a cornercorner with one Si(1)AlSi3 tetrahedra,  a cornercorner with one Si(17)AlSi3 tetrahedra,  a cornercorner with one Si(24)AlSi3 tetrahedra,  a cornercorner with one Si(35)AlSi3 tetrahedra,  a cornercorner with one Si(37)AlSi3 tetrahedra,  a cornercorner with one Si(11)Si4 tetrahedra,  a cornercorner with one Si(13)Si4 tetrahedra, and  a cornercorner with one Si(6)Si4 tetrahedra. In the twenty-third Si site, Si(23) is bonded to one Si(14), one Si(2), one Si(24), and one Si(4) atom to form SiSi4 tetrahedra that share  a cornercorner with one Al(2)Si4 tetrahedra,  a cornercorner with one Al(4)Si4 tetrahedra,  a cornercorner with one Al(5)Si4 tetrahedra,  a cornercorner with one Al(8)Si4 tetrahedra,  a cornercorner with one Si(20)Al2Si2 tetrahedra,  a cornercorner with one Si(28)Al2Si2 tetrahedra,  a cornercorner with one Si(26)AlSi3 tetrahedra,  a cornercorner with one Si(9)AlSi3 tetrahedra,  a cornercorner with one Si(13)Si4 tetrahedra,  a cornercorner with one Si(18)Si4 tetrahedra,  a cornercorner with one Si(32)Si4 tetrahedra, and  a cornercorner with one Si(7)Si4 tetrahedra. The Si(23)-Si(24) bond length is 2.37 Å. In the twenty-fourth Si site, Si(24) is bonded to one Al(2), one Si(13), one Si(23), and one Si(7) atom to form distorted SiAlSi3 tetrahedra that share  a cornercorner with one Si(2)Al2Si2 tetrahedra,  a cornercorner with one Si(25)Al2Si2 tetrahedra,  a cornercorner with one Si(28)Al2Si2 tetrahedra,  a cornercorner with one Si(34)Al2Si2 tetrahedra,  a cornercorner with one Si(22)AlSi3 tetrahedra,  a cornercorner with one Si(26)AlSi3 tetrahedra,  a cornercorner with one Si(33)AlSi3 tetrahedra,  a cornercorner with one Si(4)AlSi3 tetrahedra,  a cornercorner with one Si(11)Si4 tetrahedra,  a cornercorner with one Si(14)Si4 tetrahedra,  a cornercorner with one Si(16)Si4 tetrahedra, and  a cornercorner with one Si(21)Si4 tetrahedra. In the twenty-fifth Si site, Si(25) is bonded to one Al(2), one Al(5), one Si(12), and one Si(6) atom to form SiAl2Si2 tetrahedra that share  a cornercorner with one Al(6)Si4 tetrahedra,  a cornercorner with one Si(15)Al2Si2 tetrahedra,  a cornercorner with one Si(2)Al2Si2 tetrahedra,  a cornercorner with one Si(34)Al2Si2 tetrahedra,  a cornercorner with one Si(5)Al2Si2 tetrahedra,  a cornercorner with one Si(10)AlSi3 tetrahedra,  a cornercorner with one Si(17)AlSi3 tetrahedra,  a cornercorner with one Si(22)AlSi3 tetrahedra,  a cornercorner with one Si(24)AlSi3 tetrahedra,  a cornercorner with one Si(33)AlSi3 tetrahedra,  a cornercorner with one Si(21)Si4 tetrahedra, and  a cornercorner with one Si(27)Si4 tetrahedra. In the twenty-sixth Si site, Si(26) is bonded to one Al(3), one Si(13), one Si(27), and one Si(4) atom to form distorted SiAlSi3 tetrahedra that share  a cornercorner with one Al(4)Si4 tetrahedra,  a cornercorner with one Si(15)Al2Si2 tetrahedra,  a cornercorner with one Si(28)Al2Si2 tetrahedra,  a cornercorner with one Si(3)Al2Si2 tetrahedra,  a cornercorner with one Si(31)Al2Si2 tetrahedra,  a cornercorner with one Si(24)AlSi3 tetrahedra,  a cornercorner with one Si(30)AlSi3 tetrahedra,  a cornercorner with one Si(9)AlSi3 tetrahedra,  a cornercorner with one Si(16)Si4 tetrahedra,  a cornercorner with one Si(21)Si4 tetrahedra,  a cornercorner with one Si(23)Si4 tetrahedra, and  a cornercorner with one Si(6)Si4 tetrahedra. The Si(26)-Si(27) bond length is 2.37 Å. In the twenty-seventh Si site, Si(27) is bonded to one Si(15), one Si(26), one Si(3), and one Si(6) atom to form SiSi4 tetrahedra that share  a cornercorner with one Al(3)Si4 tetrahedra,  a cornercorner with one Al(4)Si4 tetrahedra,  a cornercorner with one Al(5)Si4 tetrahedra,  a cornercorner with one Al(6)Si4 tetrahedra,  a cornercorner with one Al(7)Si4 tetrahedra,  a cornercorner with one Si(25)Al2Si2 tetrahedra,  a cornercorner with one Si(10)AlSi3 tetrahedra,  a cornercorner with one Si(19)AlSi3 tetrahedra,  a cornercorner with one Si(4)AlSi3 tetrahedra,  a cornercorner with one Si(13)Si4 tetrahedra,  a cornercorner with one Si(21)Si4 tetrahedra, and  a cornercorner with one Si(29)Si4 tetrahedra. In the twenty-eighth Si site, Si(28) is bonded to one Al(3), one Al(6), one Si(14), and one Si(7) atom to form SiAl2Si2 tetrahedra that share  a cornercorner with one Si(20)Al2Si2 tetrahedra,  a cornercorner with one Si(3)Al2Si2 tetrahedra,  a cornercorner with one Si(31)Al2Si2 tetrahedra,  a cornercorner with one Si(5)Al2Si2 tetrahedra,  a cornercorner with one Si(12)AlSi3 tetrahedra,  a cornercorner with one Si(22)AlSi3 tetrahedra,  a cornercorner with one Si(24)AlSi3 tetrahedra,  a cornercorner with one Si(26)AlSi3 tetrahedra,  a cornercorner with one Si(30)AlSi3 tetrahedra,  a cornercorner with one Si(11)Si4 tetrahedra,  a cornercorner with one Si(18)Si4 tetrahedra, and  a cornercorner with one Si(23)Si4 tetrahedra. In the twenty-ninth Si site, Si(29) is bonded to one Si(19), one Si(3), one Si(30), and one Si(8) atom to form SiSi4 tetrahedra that share  a cornercorner with one Al(3)Si4 tetrahedra,  a cornercorner with one Al(6)Si4 tetrahedra,  a cornercorner with one Al(7)Si4 tetrahedra,  a cornercorner with one Al(8)Si4 tetrahedra,  a cornercorner with one Si(15)Al2Si2 tetrahedra,  a cornercorner with one Si(5)Al2Si2 tetrahedra,  a cornercorner with one Si(35)AlSi3 tetrahedra,  a cornercorner with one Si(9)AlSi3 tetrahedra,  a cornercorner with one Si(18)Si4 tetrahedra,  a cornercorner with one Si(27)Si4 tetrahedra,  a cornercorner with one Si(32)Si4 tetrahedra, and  a cornercorner with one Si(36)Si4 tetrahedra. The Si(29)-Si(30) bond length is 2.38 Å. In the thirtieth Si site, Si(30) is bonded to one Al(3), one Si(18), one Si(29), and one Si(9) atom to form distorted SiAlSi3 tetrahedra that share  a cornercorner with one Al(8)Si4 tetrahedra,  a cornercorner with one Si(28)Al2Si2 tetrahedra,  a cornercorner with one Si(3)Al2Si2 tetrahedra,  a cornercorner with one Si(31)Al2Si2 tetrahedra,  a cornercorner with one Si(19)AlSi3 tetrahedra,  a cornercorner with one Si(26)AlSi3 tetrahedra,  a cornercorner with one Si(37)AlSi3 tetrahedra,  a cornercorner with one Si(4)AlSi3 tetrahedra,  a cornercorner with one Si(14)Si4 tetrahedra,  a cornercorner with one Si(32)Si4 tetrahedra,  a cornercorner with one Si(38)Si4 tetrahedra, and  a cornercorner with one Si(8)Si4 tetrahedra. In the thirty-first Si site, Si(31) is bonded to one Al(3), one Al(7), one Si(11), and one Si(16) atom to form SiAl2Si2 tetrahedra that share  a cornercorner with one Si(28)Al2Si2 tetrahedra,  a cornercorner with one Si(3)Al2Si2 tetrahedra,  a cornercorner with one Si(34)Al2Si2 tetrahedra,  a cornercorner with one Si(10)AlSi3 tetrahedra,  a cornercorner with one Si(17)AlSi3 tetrahedra,  a cornercorner with one Si(26)AlSi3 tetrahedra,  a cornercorner with one Si(30)AlSi3 tetrahedra,  a cornercorner with one Si(33)AlSi3 tetrahedra,  a cornercorner with one Si(37)AlSi3 tetrahedra,  a cornercorner with one Si(13)Si4 tetrahedra,  a cornercorner with one Si(38)Si4 tetrahedra, and  a cornercorner with one Si(7)Si4 tetrahedra. In the thirty-second Si site, Si(32) is bonded to one Si(18), one Si(2), one Si(33), and one Si(8) atom to form SiSi4 tetrahedra that share  a cornercorner with one Al(2)Si4 tetrahedra,  a cornercorner with one Al(5)Si4 tetrahedra,  a cornercorner with one Al(8)Si4 tetrahedra,  a cornercorner with one Si(5)Al2Si2 tetrahedra,  a cornercorner with one Si(17)AlSi3 tetrahedra,  a cornercorner with one Si(30)AlSi3 tetrahedra,  a cornercorner with one Si(35)AlSi3 tetrahedra,  a cornercorner with one Si(37)AlSi3 tetrahedra,  a cornercorner with one Si(11)Si4 tetrahedra,  a cornercorner with one Si(14)Si4 tetrahedra,  a cornercorner with one Si(23)Si4 tetrahedra, and  a cornercorner with one Si(29)Si4 tetrahedra. The Si(32)-Si(33) bond length is 2.36 Å. In the thirty-third Si site, Si(33) is bonded to one Al(2), one Si(11), one Si(17), and one Si(32) atom to form distorted SiAlSi3 tetrahedra that share  a cornercorner with one Al(7)Si4 tetrahedra,  a cornercorner with one Si(2)Al2Si2 tetrahedra,  a cornercorner with one Si(25)Al2Si2 tetrahedra,  a cornercorner with one Si(31)Al2Si2 tetrahedra,  a cornercorner with one Si(34)Al2Si2 tetrahedra,  a cornercorner with one Si(12)AlSi3 tetrahedra,  a cornercorner with one Si(24)AlSi3 tetrahedra,  a cornercorner with one Si(35)AlSi3 tetrahedra,  a cornercorner with one Si(37)AlSi3 tetrahedra,  a cornercorner with one Si(18)Si4 tetrahedra,  a cornercorner with one Si(7)Si4 tetrahedra, and  a cornercorner with one Si(8)Si4 tetrahedra. In the thirty-fourth Si site, Si(34) is bonded to one Al(2), one Al(8), one Si(10), and one Si(16) atom to form SiAl2Si2 tetrahedra that share  a cornercorner with one Al(7)Si4 tetrahedra,  a cornercorner with one Si(2)Al2Si2 tetrahedra,  a cornercorner with one Si(25)Al2Si2 tetrahedra,  a cornercorner with one Si(31)Al2Si2 tetrahedra,  a cornercorner with one Si(19)AlSi3 tetrahedra,  a cornercorner with one Si(24)AlSi3 tetrahedra,  a cornercorner with one Si(33)AlSi3 tetrahedra,  a cornercorner with one Si(9)AlSi3 tetrahedra,  a cornercorner with one Si(13)Si4 tetrahedra,  a cornercorner with one Si(36)Si4 tetrahedra,  a cornercorner with one Si(38)Si4 tetrahedra, and  a cornercorner with one Si(6)Si4 tetrahedra. In the thirty-fifth Si site, Si(35) is bonded to one Al(1), one Si(17), one Si(36), and one Si(8) atom to form distorted SiAlSi3 tetrahedra that share  a cornercorner with one Al(7)Si4 tetrahedra,  a cornercorner with one Si(20)Al2Si2 tetrahedra,  a cornercorner with one Si(5)Al2Si2 tetrahedra,  a cornercorner with one Si(1)AlSi3 tetrahedra,  a cornercorner with one Si(10)AlSi3 tetrahedra,  a cornercorner with one Si(12)AlSi3 tetrahedra,  a cornercorner with one Si(19)AlSi3 tetrahedra,  a cornercorner with one Si(22)AlSi3 tetrahedra,  a cornercorner with one Si(33)AlSi3 tetrahedra,  a cornercorner with one Si(37)AlSi3 tetrahedra,  a cornercorner with one Si(29)Si4 tetrahedra, and  a cornercorner with one Si(32)Si4 tetrahedra. The Si(35)-Si(36) bond length is 2.37 Å. In the thirty-sixth Si site, Si(36) is bonded to one Si(1), one Si(10), one Si(19), and one Si(35) atom to form SiSi4 tetrahedra that share  a cornercorner with one Al(1)Si4 tetrahedra,  a cornercorner with one Al(4)Si4 tetrahedra,  a cornercorner with one Al(7)Si4 tetrahedra,  a cornercorner with one Al(8)Si4 tetrahedra,  a cornercorner with one Si(15)Al2Si2 tetrahedra,  a cornercorner with one Si(34)Al2Si2 tetrahedra,  a cornercorner with one Si(17)AlSi3 tetrahedra,  a cornercorner with one Si(21)Si4 tetrahedra,  a cornercorner with one Si(29)Si4 tetrahedra,  a cornercorner with one Si(38)Si4 tetrahedra,  a cornercorner with one Si(6)Si4 tetrahedra, and  a cornercorner with one Si(8)Si4 tetrahedra. In the thirty-seventh Si site, Si(37) is bonded to one Al(1), one Si(11), one Si(18), and one Si(38) atom to form SiAlSi3 tetrahedra that share  a cornercorner with one Si(20)Al2Si2 tetrahedra,  a cornercorner with one Si(31)Al2Si2 tetrahedra,  a cornercorner with one Si(1)AlSi3 tetrahedra,  a cornercorner with one Si(22)AlSi3 tetrahedra,  a cornercorner with one Si(30)AlSi3 tetrahedra,  a cornercorner with one Si(33)AlSi3 tetrahedra,  a cornercorner with one Si(35)AlSi3 tetrahedra,  a cornercorner with one Si(9)AlSi3 tetrahedra,  a cornercorner with one Si(14)Si4 tetrahedra,  a cornercorner with one Si(16)Si4 tetrahedra,  a cornercorner with one Si(32)Si4 tetrahedra, and  a cornercorner with one Si(7)Si4 tetrahedra. The Si(37)-Si(38) bond length is 2.36 Å. In the thirty-eighth Si site, Si(38) is bonded to one Si(1), one Si(16), one Si(37), and one Si(9) atom to form SiSi4 tetrahedra that share  a cornercorner with one Al(1)Si4 tetrahedra,  a cornercorner with one Al(4)Si4 tetrahedra,  a cornercorner with one Al(8)Si4 tetrahedra,  a cornercorner with one Si(31)Al2Si2 tetrahedra,  a cornercorner with one Si(34)Al2Si2 tetrahedra,  a cornercorner with one Si(30)AlSi3 tetrahedra,  a cornercorner with one Si(4)AlSi3 tetrahedra,  a cornercorner with one Si(11)Si4 tetrahedra,  a cornercorner with one Si(13)Si4 tetrahedra,  a cornercorner with one Si(18)Si4 tetrahedra,  a cornercorner with one Si(21)Si4 tetrahedra, and  a cornercorner with one Si(36)Si4 tetrahedra.