The material structure described by Na2Si3O7 crystallizes in the monoclinic C2/c space group. Na(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), and three equivalent O(4) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form corner-sharing SiO6 octahedra. In the second Si site, Si(2) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form SiO4 tetrahedra that share corners with three equivalent Si(1)O6 octahedra and  a cornercorner with one Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 21-57°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal pyramidal geometry to two equivalent Na(1) and two equivalent Si(2) atoms. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Na(1), one Si(1), and one Si(2) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Na(1), one Si(1), and one Si(2) atom. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to three equivalent Na(1), one Si(1), and one Si(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Na2Si3O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.129
_cell_length_b   5.129
_cell_length_c   11.705
_cell_angle_alpha   79.272
_cell_angle_beta   79.272
_cell_angle_gamma   57.137
_symmetry_Int_Tables_number   1
_cell_volume   252.772
_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  0.147  0.560  0.682  1.0
  Na  Na1  1  0.440  0.853  0.818  1.0
  Na  Na2  1  0.853  0.440  0.318  1.0
  Na  Na3  1  0.560  0.147  0.182  1.0
  Si  Si4  1  0.000  0.500  0.000  1.0
  Si  Si5  1  0.500  0.000  0.500  1.0
  Si  Si6  1  0.827  0.259  0.615  1.0
  Si  Si7  1  0.741  0.173  0.885  1.0
  Si  Si8  1  0.173  0.741  0.385  1.0
  Si  Si9  1  0.259  0.827  0.115  1.0
  O  O10  1  0.648  0.352  0.750  1.0
  O  O11  1  0.352  0.648  0.250  1.0
  O  O12  1  0.990  0.256  0.911  1.0
  O  O13  1  0.744  0.010  0.589  1.0
  O  O14  1  0.010  0.744  0.089  1.0
  O  O15  1  0.256  0.990  0.411  1.0
  O  O16  1  0.681  0.590  0.537  1.0
  O  O17  1  0.410  0.319  0.963  1.0
  O  O18  1  0.319  0.410  0.463  1.0
  O  O19  1  0.590  0.681  0.037  1.0
  O  O20  1  0.079  0.203  0.127  1.0
  O  O21  1  0.797  0.921  0.373  1.0
  O  O22  1  0.921  0.797  0.873  1.0
  O  O23  1  0.203  0.079  0.627  1.0
[/CIF]
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The material structure described by Na2Si3O7 crystallizes in the monoclinic C2/c space group. Na(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), and three equivalent O(4) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form corner-sharing SiO6 octahedra. In the second Si site, Si(2) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form SiO4 tetrahedra that share corners with three equivalent Si(1)O6 octahedra and  a cornercorner with one Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 21-57°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal pyramidal geometry to two equivalent Na(1) and two equivalent Si(2) atoms. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Na(1), one Si(1), and one Si(2) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Na(1), one Si(1), and one Si(2) atom. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to three equivalent Na(1), one Si(1), and one Si(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Na2Si3O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.129
_cell_length_b   5.129
_cell_length_c   11.705
_cell_angle_alpha   79.272
_cell_angle_beta   79.272
_cell_angle_gamma   57.137
_symmetry_Int_Tables_number   1
_cell_volume   252.772
_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  0.147  0.560  0.682  1.0
  Na  Na1  1  0.440  0.853  0.818  1.0
  Na  Na2  1  0.853  0.440  0.318  1.0
  Na  Na3  1  0.560  0.147  0.182  1.0
  Si  Si4  1  0.000  0.500  0.000  1.0
  Si  Si5  1  0.500  0.000  0.500  1.0
  Si  Si6  1  0.827  0.259  0.615  1.0
  Si  Si7  1  0.741  0.173  0.885  1.0
  Si  Si8  1  0.173  0.741  0.385  1.0
  Si  Si9  1  0.259  0.827  0.115  1.0
  O  O10  1  0.648  0.352  0.750  1.0
  O  O11  1  0.352  0.648  0.250  1.0
  O  O12  1  0.990  0.256  0.911  1.0
  O  O13  1  0.744  0.010  0.589  1.0
  O  O14  1  0.010  0.744  0.089  1.0
  O  O15  1  0.256  0.990  0.411  1.0
  O  O16  1  0.681  0.590  0.537  1.0
  O  O17  1  0.410  0.319  0.963  1.0
  O  O18  1  0.319  0.410  0.463  1.0
  O  O19  1  0.590  0.681  0.037  1.0
  O  O20  1  0.079  0.203  0.127  1.0
  O  O21  1  0.797  0.921  0.373  1.0
  O  O22  1  0.921  0.797  0.873  1.0
  O  O23  1  0.203  0.079  0.627  1.0
[/CIF]
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