The crystal structure described by Na2Zn2Si2O7 crystallizes in the orthorhombic Ama2 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 5-coordinate geometry to one O(4), two equivalent O(1), and two equivalent O(3) atoms. In the second Na site, Na(2) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(3), and four equivalent O(2) atoms. Zn(1) is bonded to one O(1), one O(3), and two equivalent O(2) atoms to form distorted ZnO4 tetrahedra that share corners with two equivalent Zn(1)O4 tetrahedra and corners with four equivalent Si(1)O4 tetrahedra. Si(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra and corners with four equivalent Zn(1)O4 tetrahedra. There are four inequivalent O sites. In the first O site, O(3) is bonded to one Na(1), one Na(2), one Zn(1), and one Si(1) atom to form a mixture of distorted edge and corner-sharing ONa2ZnSi trigonal pyramids. In the second O site, O(4) is bonded in a 2-coordinate geometry to one Na(1) and two equivalent Si(1) atoms. In the third O site, O(1) is bonded to one Na(1), one Na(2), one Zn(1), and one Si(1) atom to form a mixture of distorted edge and corner-sharing ONa2ZnSi trigonal pyramids. In the fourth O site, O(2) is bonded in a 3-coordinate geometry to two equivalent Na(2), two equivalent Zn(1), and one Si(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Na2Zn2Si2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.354
_cell_length_b   5.354
_cell_length_c   13.821
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   122.260
_symmetry_Int_Tables_number   1
_cell_volume   334.969
_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  0.943  0.015  0.250  1.0
  Na  Na1  1  0.015  0.943  0.750  1.0
  Na  Na2  1  0.992  0.992  0.500  1.0
  Na  Na3  1  0.992  0.992  0.000  1.0
  Zn  Zn4  1  0.228  0.657  0.420  1.0
  Zn  Zn5  1  0.657  0.228  0.580  1.0
  Zn  Zn6  1  0.228  0.657  0.080  1.0
  Zn  Zn7  1  0.657  0.228  0.920  1.0
  Si  Si8  1  0.571  0.332  0.360  1.0
  Si  Si9  1  0.332  0.571  0.640  1.0
  Si  Si10  1  0.571  0.332  0.140  1.0
  Si  Si11  1  0.332  0.571  0.860  1.0
  O  O12  1  0.279  0.352  0.371  1.0
  O  O13  1  0.352  0.279  0.629  1.0
  O  O14  1  0.279  0.352  0.129  1.0
  O  O15  1  0.352  0.279  0.871  1.0
  O  O16  1  0.550  0.082  0.437  1.0
  O  O17  1  0.082  0.550  0.563  1.0
  O  O18  1  0.550  0.082  0.063  1.0
  O  O19  1  0.082  0.550  0.937  1.0
  O  O20  1  0.876  0.651  0.374  1.0
  O  O21  1  0.651  0.876  0.626  1.0
  O  O22  1  0.876  0.651  0.126  1.0
  O  O23  1  0.651  0.876  0.874  1.0
  O  O24  1  0.192  0.563  0.750  1.0
  O  O25  1  0.563  0.192  0.250  1.0
[/CIF]
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The crystal structure described by Na2Zn2Si2O7 crystallizes in the orthorhombic Ama2 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 5-coordinate geometry to one O(4), two equivalent O(1), and two equivalent O(3) atoms. In the second Na site, Na(2) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(3), and four equivalent O(2) atoms. Zn(1) is bonded to one O(1), one O(3), and two equivalent O(2) atoms to form distorted ZnO4 tetrahedra that share corners with two equivalent Zn(1)O4 tetrahedra and corners with four equivalent Si(1)O4 tetrahedra. Si(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra and corners with four equivalent Zn(1)O4 tetrahedra. There are four inequivalent O sites. In the first O site, O(3) is bonded to one Na(1), one Na(2), one Zn(1), and one Si(1) atom to form a mixture of distorted edge and corner-sharing ONa2ZnSi trigonal pyramids. In the second O site, O(4) is bonded in a 2-coordinate geometry to one Na(1) and two equivalent Si(1) atoms. In the third O site, O(1) is bonded to one Na(1), one Na(2), one Zn(1), and one Si(1) atom to form a mixture of distorted edge and corner-sharing ONa2ZnSi trigonal pyramids. In the fourth O site, O(2) is bonded in a 3-coordinate geometry to two equivalent Na(2), two equivalent Zn(1), and one Si(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Na2Zn2Si2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.354
_cell_length_b   5.354
_cell_length_c   13.821
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   122.260
_symmetry_Int_Tables_number   1
_cell_volume   334.969
_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  0.943  0.015  0.250  1.0
  Na  Na1  1  0.015  0.943  0.750  1.0
  Na  Na2  1  0.992  0.992  0.500  1.0
  Na  Na3  1  0.992  0.992  0.000  1.0
  Zn  Zn4  1  0.228  0.657  0.420  1.0
  Zn  Zn5  1  0.657  0.228  0.580  1.0
  Zn  Zn6  1  0.228  0.657  0.080  1.0
  Zn  Zn7  1  0.657  0.228  0.920  1.0
  Si  Si8  1  0.571  0.332  0.360  1.0
  Si  Si9  1  0.332  0.571  0.640  1.0
  Si  Si10  1  0.571  0.332  0.140  1.0
  Si  Si11  1  0.332  0.571  0.860  1.0
  O  O12  1  0.279  0.352  0.371  1.0
  O  O13  1  0.352  0.279  0.629  1.0
  O  O14  1  0.279  0.352  0.129  1.0
  O  O15  1  0.352  0.279  0.871  1.0
  O  O16  1  0.550  0.082  0.437  1.0
  O  O17  1  0.082  0.550  0.563  1.0
  O  O18  1  0.550  0.082  0.063  1.0
  O  O19  1  0.082  0.550  0.937  1.0
  O  O20  1  0.876  0.651  0.374  1.0
  O  O21  1  0.651  0.876  0.626  1.0
  O  O22  1  0.876  0.651  0.126  1.0
  O  O23  1  0.651  0.876  0.874  1.0
  O  O24  1  0.192  0.563  0.750  1.0
  O  O25  1  0.563  0.192  0.250  1.0
[/CIF]
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