The compound described by (CaAl2(Si2O7)2)4(O2)3 crystallizes in the monoclinic C2 space group. The structure consists of two trioxidane molecules inside a CaAl2(Si2O7)2 framework. In the CaAl2(Si2O7)2 framework, Ca(1) is bonded in a 5-coordinate geometry to one O(1), one O(10), one O(11), one O(14), one O(16), and one O(2) atom. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(1), one O(10), one O(5), and one O(8) atom to form AlO4 tetrahedra that share  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and corners with two equivalent Si(1)O4 tetrahedra. In the second Al site, Al(2) is bonded to one O(11), one O(2), one O(4), and one O(9) atom to form AlO4 tetrahedra that share  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and corners with two equivalent Si(2)O4 tetrahedra. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(10), one O(12), one O(6), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, and corners with two equivalent Al(1)O4 tetrahedra. In the second Si site, Si(2) is bonded to one O(11), one O(12), one O(7), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and corners with two equivalent Al(2)O4 tetrahedra. In the third Si site, Si(3) is bonded to one O(1), one O(3), one O(4), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Al(1)O4 tetrahedra,  a cornercorner with one Al(2)O4 tetrahedra,  a cornercorner with one Si(1)O4 tetrahedra, and  a cornercorner with one Si(4)O4 tetrahedra. In the fourth Si site, Si(4) is bonded to one O(2), one O(3), one O(5), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Al(1)O4 tetrahedra,  a cornercorner with one Al(2)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(3)O4 tetrahedra. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Ca(1), one Al(1), and one Si(3) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Ca(1), one Al(2), and one Si(4) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Si(3) and one Si(4) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Al(2) and one Si(3) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Al(1) and one Si(4) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(3) atom. In the seventh O site, O(7) is bonded in a bent 150 degrees geometry to one Si(2) and one Si(4) atom. In the eighth O site, O(8) is bonded in a bent 150 degrees geometry to one Al(1) and one Si(1) atom. In the ninth O site, O(9) is bonded in a bent 150 degrees geometry to one Al(2) and one Si(2) atom. In the tenth O site, O(10) is bonded in a distorted trigonal planar geometry to one Ca(1), one Al(1), and one Si(1) atom. In the eleventh O site, O(11) is bonded in a distorted trigonal planar geometry to one Ca(1), one Al(2), and one Si(2) atom. In the twelfth O site, O(12) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the thirteenth O site, O(14) is bonded in an L-shaped geometry to one Ca(1) and one O(16) atom. In the fourteenth O site, O(16) is bonded in a distorted single-bond geometry to one Ca(1), one O(14), and one O(16) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ca2Al4Si8O31
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.055
_cell_length_b   10.055
_cell_length_c   7.575
_cell_angle_alpha   75.628
_cell_angle_beta   75.628
_cell_angle_gamma   83.804
_symmetry_Int_Tables_number   1
_cell_volume   717.768
_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
  Ca  Ca0  1  0.737  0.739  0.278  1.0
  Ca  Ca1  1  0.261  0.263  0.722  1.0
  Al  Al2  1  0.821  0.435  0.261  1.0
  Al  Al3  1  0.432  0.822  0.264  1.0
  Al  Al4  1  0.178  0.568  0.736  1.0
  Al  Al5  1  0.565  0.179  0.739  1.0
  Si  Si6  1  0.700  0.465  0.678  1.0
  Si  Si7  1  0.464  0.699  0.679  1.0
  Si  Si8  1  0.301  0.536  0.321  1.0
  Si  Si9  1  0.535  0.300  0.322  1.0
  Si  Si10  1  0.856  0.625  0.852  1.0
  Si  Si11  1  0.624  0.857  0.854  1.0
  Si  Si12  1  0.143  0.376  0.146  1.0
  Si  Si13  1  0.375  0.144  0.148  1.0
  O  O14  1  0.826  0.592  0.083  1.0
  O  O15  1  0.590  0.827  0.085  1.0
  O  O16  1  0.173  0.410  0.915  1.0
  O  O17  1  0.408  0.174  0.917  1.0
  O  O18  1  0.766  0.767  0.783  1.0
  O  O19  1  0.233  0.234  0.217  1.0
  O  O20  1  0.016  0.649  0.755  1.0
  O  O21  1  0.646  0.017  0.758  1.0
  O  O22  1  0.983  0.354  0.242  1.0
  O  O23  1  0.351  0.984  0.245  1.0
  O  O24  1  0.805  0.496  0.795  1.0
  O  O25  1  0.495  0.805  0.796  1.0
  O  O26  1  0.195  0.505  0.204  1.0
  O  O27  1  0.504  0.195  0.205  1.0
  O  O28  1  0.696  0.326  0.272  1.0
  O  O29  1  0.325  0.697  0.270  1.0
  O  O30  1  0.303  0.675  0.730  1.0
  O  O31  1  0.674  0.304  0.728  1.0
  O  O32  1  0.769  0.521  0.452  1.0
  O  O33  1  0.520  0.768  0.453  1.0
  O  O34  1  0.232  0.480  0.547  1.0
  O  O35  1  0.479  0.231  0.548  1.0
  O  O36  1  0.555  0.555  0.728  1.0
  O  O37  1  0.445  0.445  0.272  1.0
  O  O38  1  0.983  0.111  0.585  1.0
  O  O39  1  0.170  0.017  0.775  1.0
  O  O40  1  0.983  0.830  0.225  1.0
  O  O41  1  0.889  0.017  0.415  1.0
  O  O42  1  0.887  0.113  0.500  1.0
  O  O43  1  0.992  0.871  0.054  1.0
  O  O44  1  0.129  0.008  0.946  1.0
[/CIF]
.
The compound described by (CaAl2(Si2O7)2)4(O2)3 crystallizes in the monoclinic C2 space group. The structure consists of two trioxidane molecules inside a CaAl2(Si2O7)2 framework. In the CaAl2(Si2O7)2 framework, Ca(1) is bonded in a 5-coordinate geometry to one O(1), one O(10), one O(11), one O(14), one O(16), and one O(2) atom. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(1), one O(10), one O(5), and one O(8) atom to form AlO4 tetrahedra that share  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and corners with two equivalent Si(1)O4 tetrahedra. In the second Al site, Al(2) is bonded to one O(11), one O(2), one O(4), and one O(9) atom to form AlO4 tetrahedra that share  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and corners with two equivalent Si(2)O4 tetrahedra. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(10), one O(12), one O(6), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, and corners with two equivalent Al(1)O4 tetrahedra. In the second Si site, Si(2) is bonded to one O(11), one O(12), one O(7), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and corners with two equivalent Al(2)O4 tetrahedra. In the third Si site, Si(3) is bonded to one O(1), one O(3), one O(4), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Al(1)O4 tetrahedra,  a cornercorner with one Al(2)O4 tetrahedra,  a cornercorner with one Si(1)O4 tetrahedra, and  a cornercorner with one Si(4)O4 tetrahedra. In the fourth Si site, Si(4) is bonded to one O(2), one O(3), one O(5), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Al(1)O4 tetrahedra,  a cornercorner with one Al(2)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(3)O4 tetrahedra. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Ca(1), one Al(1), and one Si(3) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Ca(1), one Al(2), and one Si(4) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Si(3) and one Si(4) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Al(2) and one Si(3) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Al(1) and one Si(4) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(3) atom. In the seventh O site, O(7) is bonded in a bent 150 degrees geometry to one Si(2) and one Si(4) atom. In the eighth O site, O(8) is bonded in a bent 150 degrees geometry to one Al(1) and one Si(1) atom. In the ninth O site, O(9) is bonded in a bent 150 degrees geometry to one Al(2) and one Si(2) atom. In the tenth O site, O(10) is bonded in a distorted trigonal planar geometry to one Ca(1), one Al(1), and one Si(1) atom. In the eleventh O site, O(11) is bonded in a distorted trigonal planar geometry to one Ca(1), one Al(2), and one Si(2) atom. In the twelfth O site, O(12) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the thirteenth O site, O(14) is bonded in an L-shaped geometry to one Ca(1) and one O(16) atom. In the fourteenth O site, O(16) is bonded in a distorted single-bond geometry to one Ca(1), one O(14), and one O(16) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ca2Al4Si8O31
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.055
_cell_length_b   10.055
_cell_length_c   7.575
_cell_angle_alpha   75.628
_cell_angle_beta   75.628
_cell_angle_gamma   83.804
_symmetry_Int_Tables_number   1
_cell_volume   717.768
_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
  Ca  Ca0  1  0.737  0.739  0.278  1.0
  Ca  Ca1  1  0.261  0.263  0.722  1.0
  Al  Al2  1  0.821  0.435  0.261  1.0
  Al  Al3  1  0.432  0.822  0.264  1.0
  Al  Al4  1  0.178  0.568  0.736  1.0
  Al  Al5  1  0.565  0.179  0.739  1.0
  Si  Si6  1  0.700  0.465  0.678  1.0
  Si  Si7  1  0.464  0.699  0.679  1.0
  Si  Si8  1  0.301  0.536  0.321  1.0
  Si  Si9  1  0.535  0.300  0.322  1.0
  Si  Si10  1  0.856  0.625  0.852  1.0
  Si  Si11  1  0.624  0.857  0.854  1.0
  Si  Si12  1  0.143  0.376  0.146  1.0
  Si  Si13  1  0.375  0.144  0.148  1.0
  O  O14  1  0.826  0.592  0.083  1.0
  O  O15  1  0.590  0.827  0.085  1.0
  O  O16  1  0.173  0.410  0.915  1.0
  O  O17  1  0.408  0.174  0.917  1.0
  O  O18  1  0.766  0.767  0.783  1.0
  O  O19  1  0.233  0.234  0.217  1.0
  O  O20  1  0.016  0.649  0.755  1.0
  O  O21  1  0.646  0.017  0.758  1.0
  O  O22  1  0.983  0.354  0.242  1.0
  O  O23  1  0.351  0.984  0.245  1.0
  O  O24  1  0.805  0.496  0.795  1.0
  O  O25  1  0.495  0.805  0.796  1.0
  O  O26  1  0.195  0.505  0.204  1.0
  O  O27  1  0.504  0.195  0.205  1.0
  O  O28  1  0.696  0.326  0.272  1.0
  O  O29  1  0.325  0.697  0.270  1.0
  O  O30  1  0.303  0.675  0.730  1.0
  O  O31  1  0.674  0.304  0.728  1.0
  O  O32  1  0.769  0.521  0.452  1.0
  O  O33  1  0.520  0.768  0.453  1.0
  O  O34  1  0.232  0.480  0.547  1.0
  O  O35  1  0.479  0.231  0.548  1.0
  O  O36  1  0.555  0.555  0.728  1.0
  O  O37  1  0.445  0.445  0.272  1.0
  O  O38  1  0.983  0.111  0.585  1.0
  O  O39  1  0.170  0.017  0.775  1.0
  O  O40  1  0.983  0.830  0.225  1.0
  O  O41  1  0.889  0.017  0.415  1.0
  O  O42  1  0.887  0.113  0.500  1.0
  O  O43  1  0.992  0.871  0.054  1.0
  O  O44  1  0.129  0.008  0.946  1.0
[/CIF]
.