Al10Si2O19 crystallizes in the monoclinic Pm space group. There are ten inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(14), one O(2), two equivalent O(10), and two equivalent O(7) atoms to form distorted AlO6 octahedra that share corners with two equivalent Al(3)O4 tetrahedra, corners with two equivalent Al(5)O4 tetrahedra, corners with two equivalent Al(7)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, and edges with two equivalent Al(1)O6 octahedra. In the second Al site, Al(2) is bonded to one O(15), one O(17), two equivalent O(13), and two equivalent O(5) atoms to form AlO6 octahedra that share corners with two equivalent Al(4)O4 tetrahedra, corners with two equivalent Al(6)O4 tetrahedra, corners with two equivalent Al(8)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and edges with two equivalent Al(2)O6 octahedra. In the third Al site, Al(3) is bonded to one O(10), one O(11), and two equivalent O(18) atoms to form AlO4 tetrahedra that share corners with two equivalent Al(1)O6 octahedra, corners with two equivalent Al(10)O6 octahedra,  a cornercorner with one Al(5)O4 tetrahedra,  a cornercorner with one Al(7)O4 tetrahedra, and corners with two equivalent Al(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 55-64°. In the fourth Al site, Al(4) is bonded to one O(5), one O(8), and two equivalent O(16) atoms to form AlO4 tetrahedra that share corners with two equivalent Al(2)O6 octahedra, corners with two equivalent Al(9)O6 octahedra,  a cornercorner with one Al(8)O4 tetrahedra,  a cornercorner with one Si(1)O4 tetrahedra, and corners with two equivalent Al(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 52-64°. In the fifth Al site, Al(5) is bonded to one O(11), one O(7), and two equivalent O(1) atoms to form AlO4 tetrahedra that share corners with two equivalent Al(1)O6 octahedra, corners with two equivalent Al(9)O6 octahedra,  a cornercorner with one Al(3)O4 tetrahedra,  a cornercorner with one Al(7)O4 tetrahedra, and corners with two equivalent Al(5)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 55-57°. In the sixth Al site, Al(6) is bonded to one O(13), one O(9), and two equivalent O(19) atoms to form AlO4 tetrahedra that share corners with two equivalent Al(10)O6 octahedra, corners with two equivalent Al(2)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, and corners with two equivalent Al(6)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 55-65°. In the seventh Al site, Al(7) is bonded to one O(11), one O(12), and two equivalent O(2) atoms to form AlO4 tetrahedra that share corners with two equivalent Al(1)O6 octahedra, corners with two equivalent Al(10)O6 octahedra,  a cornercorner with one Al(3)O4 tetrahedra,  a cornercorner with one Al(5)O4 tetrahedra, and corners with two equivalent Al(7)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 53-65°. In the eighth Al site, Al(8) is bonded to one O(4), one O(8), and two equivalent O(17) atoms to form AlO4 tetrahedra that share corners with two equivalent Al(2)O6 octahedra, corners with two equivalent Al(9)O6 octahedra,  a cornercorner with one Al(4)O4 tetrahedra,  a cornercorner with one Si(1)O4 tetrahedra, and corners with two equivalent Al(8)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 53-63°. In the ninth Al site, Al(9) is bonded to one O(1), one O(16), two equivalent O(3), and two equivalent O(4) atoms to form AlO6 octahedra that share corners with two equivalent Al(4)O4 tetrahedra, corners with two equivalent Al(5)O4 tetrahedra, corners with two equivalent Al(8)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, and edges with two equivalent Al(9)O6 octahedra. In the tenth Al site, Al(10) is bonded to one O(18), one O(19), two equivalent O(12), and two equivalent O(6) atoms to form AlO6 octahedra that share corners with two equivalent Al(3)O4 tetrahedra, corners with two equivalent Al(6)O4 tetrahedra, corners with two equivalent Al(7)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and edges with two equivalent Al(10)O6 octahedra. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(3), one O(8), and two equivalent O(14) atoms to form SiO4 tetrahedra that share corners with two equivalent Al(1)O6 octahedra, corners with two equivalent Al(9)O6 octahedra,  a cornercorner with one Al(4)O4 tetrahedra,  a cornercorner with one Al(8)O4 tetrahedra, and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 50-62°. In the second Si site, Si(2) is bonded to one O(6), one O(9), and two equivalent O(15) atoms to form SiO4 tetrahedra that share corners with two equivalent Al(10)O6 octahedra, corners with two equivalent Al(2)O6 octahedra,  a cornercorner with one Al(6)O4 tetrahedra, and corners with two equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 49-67°. There are nineteen inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Al(9) and two equivalent Al(5) atoms. In the second O site, O(2) is bonded in a trigonal non-coplanar geometry to one Al(1) and two equivalent Al(7) atoms. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to two equivalent Al(9) and one Si(1) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Al(8) and two equivalent Al(9) atoms. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one Al(4) and two equivalent Al(2) atoms. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to two equivalent Al(10) and one Si(2) atom. In the seventh O site, O(7) is bonded in a trigonal planar geometry to one Al(5) and two equivalent Al(1) atoms. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Al(4), one Al(8), and one Si(1) atom. In the ninth O site, O(9) is bonded in a bent 120 degrees geometry to one Al(6) and one Si(2) atom. In the tenth O site, O(10) is bonded in a trigonal planar geometry to one Al(3) and two equivalent Al(1) atoms. In the eleventh O site, O(11) is bonded in a trigonal planar geometry to one Al(3), one Al(5), and one Al(7) atom. In the twelfth O site, O(12) is bonded in a distorted trigonal planar geometry to one Al(7) and two equivalent Al(10) atoms. In the thirteenth O site, O(13) is bonded in a trigonal planar geometry to one Al(6) and two equivalent Al(2) atoms. In the fourteenth O site, O(14) is bonded in a trigonal planar geometry to one Al(1) and two equivalent Si(1) atoms. In the fifteenth O site, O(15) is bonded in a trigonal non-coplanar geometry to one Al(2) and two equivalent Si(2) atoms. In the sixteenth O site, O(16) is bonded in a trigonal non-coplanar geometry to one Al(9) and two equivalent Al(4) atoms. In the seventeenth O site, O(17) is bonded in a trigonal planar geometry to one Al(2) and two equivalent Al(8) atoms. In the eighteenth O site, O(18) is bonded in a trigonal non-coplanar geometry to one Al(10) and two equivalent Al(3) atoms. In the nineteenth O site, O(19) is bonded in a trigonal non-coplanar geometry to one Al(10) and two equivalent Al(6) atoms.
Al10Si2O19 crystallizes in the monoclinic Pm space group. There are ten inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(14), one O(2), two equivalent O(10), and two equivalent O(7) atoms to form distorted AlO6 octahedra that share corners with two equivalent Al(3)O4 tetrahedra, corners with two equivalent Al(5)O4 tetrahedra, corners with two equivalent Al(7)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, and edges with two equivalent Al(1)O6 octahedra. The Al(1)-O(14) bond length is 2.28 Å. The Al(1)-O(2) bond length is 1.90 Å. Both Al(1)-O(10) bond lengths are 1.91 Å. Both Al(1)-O(7) bond lengths are 1.91 Å. In the second Al site, Al(2) is bonded to one O(15), one O(17), two equivalent O(13), and two equivalent O(5) atoms to form AlO6 octahedra that share corners with two equivalent Al(4)O4 tetrahedra, corners with two equivalent Al(6)O4 tetrahedra, corners with two equivalent Al(8)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and edges with two equivalent Al(2)O6 octahedra. The Al(2)-O(15) bond length is 2.11 Å. The Al(2)-O(17) bond length is 1.95 Å. Both Al(2)-O(13) bond lengths are 1.89 Å. Both Al(2)-O(5) bond lengths are 1.95 Å. In the third Al site, Al(3) is bonded to one O(10), one O(11), and two equivalent O(18) atoms to form AlO4 tetrahedra that share corners with two equivalent Al(1)O6 octahedra, corners with two equivalent Al(10)O6 octahedra,  a cornercorner with one Al(5)O4 tetrahedra,  a cornercorner with one Al(7)O4 tetrahedra, and corners with two equivalent Al(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 55-64°. The Al(3)-O(10) bond length is 1.77 Å. The Al(3)-O(11) bond length is 1.81 Å. Both Al(3)-O(18) bond lengths are 1.76 Å. In the fourth Al site, Al(4) is bonded to one O(5), one O(8), and two equivalent O(16) atoms to form AlO4 tetrahedra that share corners with two equivalent Al(2)O6 octahedra, corners with two equivalent Al(9)O6 octahedra,  a cornercorner with one Al(8)O4 tetrahedra,  a cornercorner with one Si(1)O4 tetrahedra, and corners with two equivalent Al(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 52-64°. The Al(4)-O(5) bond length is 1.73 Å. The Al(4)-O(8) bond length is 1.96 Å. Both Al(4)-O(16) bond lengths are 1.76 Å. In the fifth Al site, Al(5) is bonded to one O(11), one O(7), and two equivalent O(1) atoms to form AlO4 tetrahedra that share corners with two equivalent Al(1)O6 octahedra, corners with two equivalent Al(9)O6 octahedra,  a cornercorner with one Al(3)O4 tetrahedra,  a cornercorner with one Al(7)O4 tetrahedra, and corners with two equivalent Al(5)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 55-57°. The Al(5)-O(11) bond length is 1.78 Å. The Al(5)-O(7) bond length is 1.75 Å. Both Al(5)-O(1) bond lengths are 1.76 Å. In the sixth Al site, Al(6) is bonded to one O(13), one O(9), and two equivalent O(19) atoms to form AlO4 tetrahedra that share corners with two equivalent Al(10)O6 octahedra, corners with two equivalent Al(2)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, and corners with two equivalent Al(6)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 55-65°. The Al(6)-O(13) bond length is 1.81 Å. The Al(6)-O(9) bond length is 1.79 Å. Both Al(6)-O(19) bond lengths are 1.77 Å. In the seventh Al site, Al(7) is bonded to one O(11), one O(12), and two equivalent O(2) atoms to form AlO4 tetrahedra that share corners with two equivalent Al(1)O6 octahedra, corners with two equivalent Al(10)O6 octahedra,  a cornercorner with one Al(3)O4 tetrahedra,  a cornercorner with one Al(5)O4 tetrahedra, and corners with two equivalent Al(7)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 53-65°. The Al(7)-O(11) bond length is 1.86 Å. The Al(7)-O(12) bond length is 1.75 Å. Both Al(7)-O(2) bond lengths are 1.77 Å. In the eighth Al site, Al(8) is bonded to one O(4), one O(8), and two equivalent O(17) atoms to form AlO4 tetrahedra that share corners with two equivalent Al(2)O6 octahedra, corners with two equivalent Al(9)O6 octahedra,  a cornercorner with one Al(4)O4 tetrahedra,  a cornercorner with one Si(1)O4 tetrahedra, and corners with two equivalent Al(8)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 53-63°. The Al(8)-O(4) bond length is 1.76 Å. The Al(8)-O(8) bond length is 1.87 Å. Both Al(8)-O(17) bond lengths are 1.74 Å. In the ninth Al site, Al(9) is bonded to one O(1), one O(16), two equivalent O(3), and two equivalent O(4) atoms to form AlO6 octahedra that share corners with two equivalent Al(4)O4 tetrahedra, corners with two equivalent Al(5)O4 tetrahedra, corners with two equivalent Al(8)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, and edges with two equivalent Al(9)O6 octahedra. The Al(9)-O(1) bond length is 1.88 Å. The Al(9)-O(16) bond length is 1.98 Å. Both Al(9)-O(3) bond lengths are 1.98 Å. Both Al(9)-O(4) bond lengths are 1.89 Å. In the tenth Al site, Al(10) is bonded to one O(18), one O(19), two equivalent O(12), and two equivalent O(6) atoms to form AlO6 octahedra that share corners with two equivalent Al(3)O4 tetrahedra, corners with two equivalent Al(6)O4 tetrahedra, corners with two equivalent Al(7)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and edges with two equivalent Al(10)O6 octahedra. The Al(10)-O(18) bond length is 1.93 Å. The Al(10)-O(19) bond length is 1.90 Å. Both Al(10)-O(12) bond lengths are 1.92 Å. Both Al(10)-O(6) bond lengths are 1.95 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(3), one O(8), and two equivalent O(14) atoms to form SiO4 tetrahedra that share corners with two equivalent Al(1)O6 octahedra, corners with two equivalent Al(9)O6 octahedra,  a cornercorner with one Al(4)O4 tetrahedra,  a cornercorner with one Al(8)O4 tetrahedra, and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 50-62°. The Si(1)-O(3) bond length is 1.61 Å. The Si(1)-O(8) bond length is 1.66 Å. Both Si(1)-O(14) bond lengths are 1.68 Å. In the second Si site, Si(2) is bonded to one O(6), one O(9), and two equivalent O(15) atoms to form SiO4 tetrahedra that share corners with two equivalent Al(10)O6 octahedra, corners with two equivalent Al(2)O6 octahedra,  a cornercorner with one Al(6)O4 tetrahedra, and corners with two equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 49-67°. The Si(2)-O(6) bond length is 1.63 Å. The Si(2)-O(9) bond length is 1.60 Å. Both Si(2)-O(15) bond lengths are 1.73 Å. There are nineteen inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Al(9) and two equivalent Al(5) atoms. In the second O site, O(2) is bonded in a trigonal non-coplanar geometry to one Al(1) and two equivalent Al(7) atoms. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to two equivalent Al(9) and one Si(1) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Al(8) and two equivalent Al(9) atoms. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one Al(4) and two equivalent Al(2) atoms. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to two equivalent Al(10) and one Si(2) atom. In the seventh O site, O(7) is bonded in a trigonal planar geometry to one Al(5) and two equivalent Al(1) atoms. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Al(4), one Al(8), and one Si(1) atom. In the ninth O site, O(9) is bonded in a bent 120 degrees geometry to one Al(6) and one Si(2) atom. In the tenth O site, O(10) is bonded in a trigonal planar geometry to one Al(3) and two equivalent Al(1) atoms. In the eleventh O site, O(11) is bonded in a trigonal planar geometry to one Al(3), one Al(5), and one Al(7) atom. In the twelfth O site, O(12) is bonded in a distorted trigonal planar geometry to one Al(7) and two equivalent Al(10) atoms. In the thirteenth O site, O(13) is bonded in a trigonal planar geometry to one Al(6) and two equivalent Al(2) atoms. In the fourteenth O site, O(14) is bonded in a trigonal planar geometry to one Al(1) and two equivalent Si(1) atoms. In the fifteenth O site, O(15) is bonded in a trigonal non-coplanar geometry to one Al(2) and two equivalent Si(2) atoms. In the sixteenth O site, O(16) is bonded in a trigonal non-coplanar geometry to one Al(9) and two equivalent Al(4) atoms. In the seventeenth O site, O(17) is bonded in a trigonal planar geometry to one Al(2) and two equivalent Al(8) atoms. In the eighteenth O site, O(18) is bonded in a trigonal non-coplanar geometry to one Al(10) and two equivalent Al(3) atoms. In the nineteenth O site, O(19) is bonded in a trigonal non-coplanar geometry to one Al(10) and two equivalent Al(6) atoms.