The structure described by 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. is represented by the CIF file [CIF]
data_Al10Si2O19
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   2.950
_cell_length_b   7.485
_cell_length_c   16.050
_cell_angle_alpha   89.806
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   354.438
_cell_formula_units_Z   1
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  Al  Al0  1  0.000  0.011  0.006  1.0
  Al  Al1  1  0.000  0.986  0.498  1.0
  Al  Al2  1  0.500  0.349  0.914  1.0
  Al  Al3  1  0.500  0.254  0.361  1.0
  Al  Al4  1  0.500  0.649  0.071  1.0
  Al  Al5  1  0.500  0.769  0.650  1.0
  Al  Al6  1  0.500  0.747  0.889  1.0
  Al  Al7  1  0.500  0.839  0.339  1.0
  Al  Al8  1  0.000  0.519  0.237  1.0
  Al  Al9  1  0.000  0.482  0.754  1.0
  Si  Si10  1  0.500  0.146  0.186  1.0
  Si  Si11  1  0.500  0.155  0.657  1.0
  O  O12  1  0.000  0.597  0.125  1.0
  O  O13  1  0.000  0.873  0.907  1.0
  O  O14  1  0.500  0.358  0.203  1.0
  O  O15  1  0.500  0.661  0.268  1.0
  O  O16  1  0.500  0.124  0.450  1.0
  O  O17  1  0.500  0.340  0.710  1.0
  O  O18  1  0.500  0.879  0.049  1.0
  O  O19  1  0.500  0.057  0.281  1.0
  O  O20  1  0.500  0.972  0.709  1.0
  O  O21  1  0.500  0.168  0.986  1.0
  O  O22  1  0.500  0.562  0.967  1.0
  O  O23  1  0.500  0.615  0.799  1.0
  O  O24  1  0.500  0.871  0.548  1.0
  O  O25  1  0.000  0.097  0.141  1.0
  O  O26  1  0.000  0.163  0.600  1.0
  O  O27  1  0.000  0.374  0.340  1.0
  O  O28  1  0.000  0.843  0.397  1.0
  O  O29  1  0.000  0.340  0.855  1.0
  O  O30  1  0.000  0.641  0.662  1.0
[/CIF]
.
The structure described by 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. is represented by the CIF file [CIF]
data_Al10Si2O19
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   2.950
_cell_length_b   7.485
_cell_length_c   16.050
_cell_angle_alpha   89.806
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   354.438
_cell_formula_units_Z   1
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  Al  Al0  1  0.000  0.011  0.006  1.0
  Al  Al1  1  0.000  0.986  0.498  1.0
  Al  Al2  1  0.500  0.349  0.914  1.0
  Al  Al3  1  0.500  0.254  0.361  1.0
  Al  Al4  1  0.500  0.649  0.071  1.0
  Al  Al5  1  0.500  0.769  0.650  1.0
  Al  Al6  1  0.500  0.747  0.889  1.0
  Al  Al7  1  0.500  0.839  0.339  1.0
  Al  Al8  1  0.000  0.519  0.237  1.0
  Al  Al9  1  0.000  0.482  0.754  1.0
  Si  Si10  1  0.500  0.146  0.186  1.0
  Si  Si11  1  0.500  0.155  0.657  1.0
  O  O12  1  0.000  0.597  0.125  1.0
  O  O13  1  0.000  0.873  0.907  1.0
  O  O14  1  0.500  0.358  0.203  1.0
  O  O15  1  0.500  0.661  0.268  1.0
  O  O16  1  0.500  0.124  0.450  1.0
  O  O17  1  0.500  0.340  0.710  1.0
  O  O18  1  0.500  0.879  0.049  1.0
  O  O19  1  0.500  0.057  0.281  1.0
  O  O20  1  0.500  0.972  0.709  1.0
  O  O21  1  0.500  0.168  0.986  1.0
  O  O22  1  0.500  0.562  0.967  1.0
  O  O23  1  0.500  0.615  0.799  1.0
  O  O24  1  0.500  0.871  0.548  1.0
  O  O25  1  0.000  0.097  0.141  1.0
  O  O26  1  0.000  0.163  0.600  1.0
  O  O27  1  0.000  0.374  0.340  1.0
  O  O28  1  0.000  0.843  0.397  1.0
  O  O29  1  0.000  0.340  0.855  1.0
  O  O30  1  0.000  0.641  0.662  1.0
[/CIF]
.