The material described by Na3YSi6O15 crystallizes in the monoclinic C2/m space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to one O(4), one O(5), one O(6), one O(7), one O(8), and one O(9) atom. In the second Na site, Na(2) is bonded to one O(2), two equivalent O(3), and two equivalent O(8) atoms to form distorted NaO5 square pyramids that share corners with four equivalent Si(1)O4 tetrahedra,  an edgeedge with one Y(1)O6 octahedra, and edges with two equivalent Si(2)O4 tetrahedra. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded to two equivalent O(4) and four equivalent O(8) atoms to form YO6 octahedra that share corners with two equivalent Si(3)O4 tetrahedra, corners with four equivalent Si(2)O4 tetrahedra, and edges with two equivalent Na(2)O5 square pyramids. In the second Y site, Y(2) is bonded to two equivalent O(5) and four equivalent O(9) atoms to form YO6 octahedra that share corners with two equivalent Si(4)O4 tetrahedra and corners with four equivalent Si(1)O4 tetrahedra. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(3), one O(6), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Y(2)O6 octahedra, corners with two equivalent Na(2)O5 square pyramids,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(3)O4 tetrahedra. The corner-sharing octahedral tilt angles are 44°. In the second Si site, Si(2) is bonded to one O(1), one O(3), one O(7), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Y(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and  an edgeedge with one Na(2)O5 square pyramid. The corner-sharing octahedral tilt angles are 44°. In the third Si site, Si(3) is bonded to one O(10), one O(4), and two equivalent O(6) atoms to form SiO4 tetrahedra that share  a cornercorner with one Y(1)O6 octahedra,  a cornercorner with one Si(4)O4 tetrahedra, and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 18°. In the fourth Si site, Si(4) is bonded to one O(10), one O(5), and two equivalent O(7) atoms to form SiO4 tetrahedra that share  a cornercorner with one Y(2)O6 octahedra,  a cornercorner with one Si(3)O4 tetrahedra, and corners with two equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 18°. There are ten inequivalent O sites. In the first O site, O(10) is bonded in a bent 120 degrees geometry to one Si(3) and one Si(4) atom. In the second O site, O(1) is bonded in a bent 120 degrees geometry to two equivalent Si(2) atoms. In the third O site, O(2) is bonded in a distorted trigonal non-coplanar geometry to one Na(2) and two equivalent Si(1) atoms. In the fourth O site, O(3) is bonded in a 3-coordinate geometry to one Na(2), one Si(1), and one Si(2) atom. In the fifth O site, O(4) is bonded in a distorted see-saw-like geometry to two equivalent Na(1), one Y(1), and one Si(3) atom. In the sixth O site, O(5) is bonded in a distorted see-saw-like geometry to two equivalent Na(1), one Y(2), and one Si(4) atom. In the seventh O site, O(6) is bonded in a 3-coordinate geometry to one Na(1), one Si(1), and one Si(3) atom. In the eighth O site, O(7) is bonded in a 3-coordinate geometry to one Na(1), one Si(2), and one Si(4) atom. In the ninth O site, O(8) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Y(1), and one Si(2) atom. In the tenth O site, O(9) is bonded in a distorted trigonal planar geometry to one Na(1), one Y(2), and one Si(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Na3Y(Si2O5)3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.276
_cell_length_b   10.276
_cell_length_c   10.620
_cell_angle_alpha   59.046
_cell_angle_beta   59.046
_cell_angle_gamma   48.904
_symmetry_Int_Tables_number   1
_cell_volume   697.319
_cell_formula_units_Z   2
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
  Na  Na0  1  0.260  0.759  0.741  1.0
  Na  Na1  1  0.759  0.260  0.741  1.0
  Na  Na2  1  0.740  0.241  0.259  1.0
  Na  Na3  1  0.241  0.740  0.259  1.0
  Na  Na4  1  0.790  0.790  0.883  1.0
  Na  Na5  1  0.210  0.210  0.117  1.0
  Y  Y6  1  0.000  0.000  0.500  1.0
  Y  Y7  1  0.500  0.500  0.000  1.0
  Si  Si8  1  0.671  0.029  0.117  1.0
  Si  Si9  1  0.527  0.172  0.684  1.0
  Si  Si10  1  0.172  0.527  0.684  1.0
  Si  Si11  1  0.029  0.671  0.117  1.0
  Si  Si12  1  0.329  0.971  0.883  1.0
  Si  Si13  1  0.473  0.828  0.316  1.0
  Si  Si14  1  0.828  0.473  0.316  1.0
  Si  Si15  1  0.971  0.329  0.883  1.0
  Si  Si16  1  0.847  0.847  0.368  1.0
  Si  Si17  1  0.347  0.347  0.437  1.0
  Si  Si18  1  0.153  0.153  0.632  1.0
  Si  Si19  1  0.653  0.653  0.563  1.0
  O  O20  1  0.363  0.363  0.735  1.0
  O  O21  1  0.862  0.862  0.040  1.0
  O  O22  1  0.637  0.637  0.265  1.0
  O  O23  1  0.138  0.138  0.960  1.0
  O  O24  1  0.014  0.486  0.820  1.0
  O  O25  1  0.986  0.513  0.180  1.0
  O  O26  1  0.513  0.986  0.180  1.0
  O  O27  1  0.486  0.014  0.820  1.0
  O  O28  1  0.075  0.075  0.609  1.0
  O  O29  1  0.575  0.575  0.740  1.0
  O  O30  1  0.925  0.925  0.391  1.0
  O  O31  1  0.425  0.425  0.260  1.0
  O  O32  1  0.297  0.989  0.737  1.0
  O  O33  1  0.489  0.797  0.477  1.0
  O  O34  1  0.797  0.489  0.477  1.0
  O  O35  1  0.989  0.297  0.737  1.0
  O  O36  1  0.703  0.011  0.263  1.0
  O  O37  1  0.511  0.203  0.523  1.0
  O  O38  1  0.203  0.511  0.523  1.0
  O  O39  1  0.011  0.703  0.263  1.0
  O  O40  1  0.277  0.893  0.329  1.0
  O  O41  1  0.389  0.778  0.002  1.0
  O  O42  1  0.778  0.389  0.002  1.0
  O  O43  1  0.893  0.277  0.329  1.0
  O  O44  1  0.723  0.107  0.671  1.0
  O  O45  1  0.611  0.222  0.998  1.0
  O  O46  1  0.222  0.611  0.998  1.0
  O  O47  1  0.107  0.723  0.671  1.0
  O  O48  1  0.250  0.250  0.473  1.0
  O  O49  1  0.750  0.750  0.527  1.0
[/CIF]
.
The material described by Na3YSi6O15 crystallizes in the monoclinic C2/m space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to one O(4), one O(5), one O(6), one O(7), one O(8), and one O(9) atom. In the second Na site, Na(2) is bonded to one O(2), two equivalent O(3), and two equivalent O(8) atoms to form distorted NaO5 square pyramids that share corners with four equivalent Si(1)O4 tetrahedra,  an edgeedge with one Y(1)O6 octahedra, and edges with two equivalent Si(2)O4 tetrahedra. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded to two equivalent O(4) and four equivalent O(8) atoms to form YO6 octahedra that share corners with two equivalent Si(3)O4 tetrahedra, corners with four equivalent Si(2)O4 tetrahedra, and edges with two equivalent Na(2)O5 square pyramids. In the second Y site, Y(2) is bonded to two equivalent O(5) and four equivalent O(9) atoms to form YO6 octahedra that share corners with two equivalent Si(4)O4 tetrahedra and corners with four equivalent Si(1)O4 tetrahedra. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(3), one O(6), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Y(2)O6 octahedra, corners with two equivalent Na(2)O5 square pyramids,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(3)O4 tetrahedra. The corner-sharing octahedral tilt angles are 44°. In the second Si site, Si(2) is bonded to one O(1), one O(3), one O(7), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Y(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and  an edgeedge with one Na(2)O5 square pyramid. The corner-sharing octahedral tilt angles are 44°. In the third Si site, Si(3) is bonded to one O(10), one O(4), and two equivalent O(6) atoms to form SiO4 tetrahedra that share  a cornercorner with one Y(1)O6 octahedra,  a cornercorner with one Si(4)O4 tetrahedra, and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 18°. In the fourth Si site, Si(4) is bonded to one O(10), one O(5), and two equivalent O(7) atoms to form SiO4 tetrahedra that share  a cornercorner with one Y(2)O6 octahedra,  a cornercorner with one Si(3)O4 tetrahedra, and corners with two equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 18°. There are ten inequivalent O sites. In the first O site, O(10) is bonded in a bent 120 degrees geometry to one Si(3) and one Si(4) atom. In the second O site, O(1) is bonded in a bent 120 degrees geometry to two equivalent Si(2) atoms. In the third O site, O(2) is bonded in a distorted trigonal non-coplanar geometry to one Na(2) and two equivalent Si(1) atoms. In the fourth O site, O(3) is bonded in a 3-coordinate geometry to one Na(2), one Si(1), and one Si(2) atom. In the fifth O site, O(4) is bonded in a distorted see-saw-like geometry to two equivalent Na(1), one Y(1), and one Si(3) atom. In the sixth O site, O(5) is bonded in a distorted see-saw-like geometry to two equivalent Na(1), one Y(2), and one Si(4) atom. In the seventh O site, O(6) is bonded in a 3-coordinate geometry to one Na(1), one Si(1), and one Si(3) atom. In the eighth O site, O(7) is bonded in a 3-coordinate geometry to one Na(1), one Si(2), and one Si(4) atom. In the ninth O site, O(8) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Y(1), and one Si(2) atom. In the tenth O site, O(9) is bonded in a distorted trigonal planar geometry to one Na(1), one Y(2), and one Si(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Na3Y(Si2O5)3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.276
_cell_length_b   10.276
_cell_length_c   10.620
_cell_angle_alpha   59.046
_cell_angle_beta   59.046
_cell_angle_gamma   48.904
_symmetry_Int_Tables_number   1
_cell_volume   697.319
_cell_formula_units_Z   2
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
  Na  Na0  1  0.260  0.759  0.741  1.0
  Na  Na1  1  0.759  0.260  0.741  1.0
  Na  Na2  1  0.740  0.241  0.259  1.0
  Na  Na3  1  0.241  0.740  0.259  1.0
  Na  Na4  1  0.790  0.790  0.883  1.0
  Na  Na5  1  0.210  0.210  0.117  1.0
  Y  Y6  1  0.000  0.000  0.500  1.0
  Y  Y7  1  0.500  0.500  0.000  1.0
  Si  Si8  1  0.671  0.029  0.117  1.0
  Si  Si9  1  0.527  0.172  0.684  1.0
  Si  Si10  1  0.172  0.527  0.684  1.0
  Si  Si11  1  0.029  0.671  0.117  1.0
  Si  Si12  1  0.329  0.971  0.883  1.0
  Si  Si13  1  0.473  0.828  0.316  1.0
  Si  Si14  1  0.828  0.473  0.316  1.0
  Si  Si15  1  0.971  0.329  0.883  1.0
  Si  Si16  1  0.847  0.847  0.368  1.0
  Si  Si17  1  0.347  0.347  0.437  1.0
  Si  Si18  1  0.153  0.153  0.632  1.0
  Si  Si19  1  0.653  0.653  0.563  1.0
  O  O20  1  0.363  0.363  0.735  1.0
  O  O21  1  0.862  0.862  0.040  1.0
  O  O22  1  0.637  0.637  0.265  1.0
  O  O23  1  0.138  0.138  0.960  1.0
  O  O24  1  0.014  0.486  0.820  1.0
  O  O25  1  0.986  0.513  0.180  1.0
  O  O26  1  0.513  0.986  0.180  1.0
  O  O27  1  0.486  0.014  0.820  1.0
  O  O28  1  0.075  0.075  0.609  1.0
  O  O29  1  0.575  0.575  0.740  1.0
  O  O30  1  0.925  0.925  0.391  1.0
  O  O31  1  0.425  0.425  0.260  1.0
  O  O32  1  0.297  0.989  0.737  1.0
  O  O33  1  0.489  0.797  0.477  1.0
  O  O34  1  0.797  0.489  0.477  1.0
  O  O35  1  0.989  0.297  0.737  1.0
  O  O36  1  0.703  0.011  0.263  1.0
  O  O37  1  0.511  0.203  0.523  1.0
  O  O38  1  0.203  0.511  0.523  1.0
  O  O39  1  0.011  0.703  0.263  1.0
  O  O40  1  0.277  0.893  0.329  1.0
  O  O41  1  0.389  0.778  0.002  1.0
  O  O42  1  0.778  0.389  0.002  1.0
  O  O43  1  0.893  0.277  0.329  1.0
  O  O44  1  0.723  0.107  0.671  1.0
  O  O45  1  0.611  0.222  0.998  1.0
  O  O46  1  0.222  0.611  0.998  1.0
  O  O47  1  0.107  0.723  0.671  1.0
  O  O48  1  0.250  0.250  0.473  1.0
  O  O49  1  0.750  0.750  0.527  1.0
[/CIF]
.