The structure described by Na2Zr(SiO4)2 crystallizes in the monoclinic Cc space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 9-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), one O(6), one O(7), and two equivalent O(8) atoms. In the second Na site, Na(2) is bonded in a 5-coordinate geometry to one O(1), one O(3), one O(4), one O(5), and one O(8) atom. Zr(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form ZrO6 octahedra that share corners with three equivalent Si(1)O4 tetrahedra and corners with three equivalent Si(2)O4 tetrahedra. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(3), one O(5), and one O(7) atom to form SiO4 tetrahedra that share corners with three equivalent Zr(1)O6 octahedra and  a cornercorner with one Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 16-40°. In the second Si site, Si(2) is bonded to one O(2), one O(4), one O(6), and one O(7) atom to form SiO4 tetrahedra that share corners with three equivalent Zr(1)O6 octahedra and  a cornercorner with one Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 16-36°. There are eight inequivalent O sites. In the first O site, O(7) is bonded in a 3-coordinate geometry to one Na(1), one Si(1), and one Si(2) atom. In the second O site, O(8) is bonded in a 2-coordinate geometry to one Na(2) and two equivalent Na(1) atoms. In the third O site, O(1) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Zr(1), and one Si(1) atom. In the fourth O site, O(2) is bonded in a distorted bent 150 degrees geometry to one Na(1), one Zr(1), and one Si(2) atom. In the fifth O site, O(3) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Zr(1), and one Si(1) atom. In the sixth O site, O(4) is bonded in a 3-coordinate geometry to one Na(1), one Na(2), one Zr(1), and one Si(2) atom. In the seventh O site, O(5) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Zr(1), and one Si(1) atom. In the eighth O site, O(6) is bonded in a 3-coordinate geometry to one Na(1), one Zr(1), and one Si(2) atom. is represented by the CIF file [CIF]
data_Na2Zr(SiO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.441
_cell_length_b   5.441
_cell_length_c   13.323
_cell_angle_alpha   91.866
_cell_angle_beta   91.866
_cell_angle_gamma   118.925
_symmetry_Int_Tables_number   1
_cell_volume   344.492
_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  0.941  0.015  0.255  1.0
  Na  Na1  1  0.015  0.941  0.755  1.0
  Na  Na2  1  0.284  0.652  0.403  1.0
  Na  Na3  1  0.652  0.284  0.903  1.0
  Zr  Zr4  1  0.996  0.998  0.508  1.0
  Zr  Zr5  1  0.998  0.996  0.008  1.0
  Si  Si6  1  0.633  0.323  0.373  1.0
  Si  Si7  1  0.679  0.371  0.135  1.0
  Si  Si8  1  0.371  0.679  0.635  1.0
  Si  Si9  1  0.323  0.633  0.873  1.0
  O  O10  1  0.728  0.652  0.404  1.0
  O  O11  1  0.348  0.270  0.103  1.0
  O  O12  1  0.270  0.348  0.603  1.0
  O  O13  1  0.652  0.728  0.904  1.0
  O  O14  1  0.839  0.224  0.430  1.0
  O  O15  1  0.777  0.182  0.067  1.0
  O  O16  1  0.182  0.777  0.567  1.0
  O  O17  1  0.224  0.839  0.930  1.0
  O  O18  1  0.300  0.116  0.389  1.0
  O  O19  1  0.879  0.703  0.116  1.0
  O  O20  1  0.703  0.879  0.616  1.0
  O  O21  1  0.116  0.300  0.889  1.0
  O  O22  1  0.704  0.305  0.254  1.0
  O  O23  1  0.305  0.704  0.754  1.0
  O  O24  1  0.401  0.613  0.234  1.0
  O  O25  1  0.613  0.401  0.734  1.0
[/CIF]
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The structure described by Na2Zr(SiO4)2 crystallizes in the monoclinic Cc space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 9-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), one O(6), one O(7), and two equivalent O(8) atoms. In the second Na site, Na(2) is bonded in a 5-coordinate geometry to one O(1), one O(3), one O(4), one O(5), and one O(8) atom. Zr(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form ZrO6 octahedra that share corners with three equivalent Si(1)O4 tetrahedra and corners with three equivalent Si(2)O4 tetrahedra. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(3), one O(5), and one O(7) atom to form SiO4 tetrahedra that share corners with three equivalent Zr(1)O6 octahedra and  a cornercorner with one Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 16-40°. In the second Si site, Si(2) is bonded to one O(2), one O(4), one O(6), and one O(7) atom to form SiO4 tetrahedra that share corners with three equivalent Zr(1)O6 octahedra and  a cornercorner with one Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 16-36°. There are eight inequivalent O sites. In the first O site, O(7) is bonded in a 3-coordinate geometry to one Na(1), one Si(1), and one Si(2) atom. In the second O site, O(8) is bonded in a 2-coordinate geometry to one Na(2) and two equivalent Na(1) atoms. In the third O site, O(1) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Zr(1), and one Si(1) atom. In the fourth O site, O(2) is bonded in a distorted bent 150 degrees geometry to one Na(1), one Zr(1), and one Si(2) atom. In the fifth O site, O(3) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Zr(1), and one Si(1) atom. In the sixth O site, O(4) is bonded in a 3-coordinate geometry to one Na(1), one Na(2), one Zr(1), and one Si(2) atom. In the seventh O site, O(5) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Zr(1), and one Si(1) atom. In the eighth O site, O(6) is bonded in a 3-coordinate geometry to one Na(1), one Zr(1), and one Si(2) atom. is represented by the CIF file [CIF]
data_Na2Zr(SiO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.441
_cell_length_b   5.441
_cell_length_c   13.323
_cell_angle_alpha   91.866
_cell_angle_beta   91.866
_cell_angle_gamma   118.925
_symmetry_Int_Tables_number   1
_cell_volume   344.492
_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  0.941  0.015  0.255  1.0
  Na  Na1  1  0.015  0.941  0.755  1.0
  Na  Na2  1  0.284  0.652  0.403  1.0
  Na  Na3  1  0.652  0.284  0.903  1.0
  Zr  Zr4  1  0.996  0.998  0.508  1.0
  Zr  Zr5  1  0.998  0.996  0.008  1.0
  Si  Si6  1  0.633  0.323  0.373  1.0
  Si  Si7  1  0.679  0.371  0.135  1.0
  Si  Si8  1  0.371  0.679  0.635  1.0
  Si  Si9  1  0.323  0.633  0.873  1.0
  O  O10  1  0.728  0.652  0.404  1.0
  O  O11  1  0.348  0.270  0.103  1.0
  O  O12  1  0.270  0.348  0.603  1.0
  O  O13  1  0.652  0.728  0.904  1.0
  O  O14  1  0.839  0.224  0.430  1.0
  O  O15  1  0.777  0.182  0.067  1.0
  O  O16  1  0.182  0.777  0.567  1.0
  O  O17  1  0.224  0.839  0.930  1.0
  O  O18  1  0.300  0.116  0.389  1.0
  O  O19  1  0.879  0.703  0.116  1.0
  O  O20  1  0.703  0.879  0.616  1.0
  O  O21  1  0.116  0.300  0.889  1.0
  O  O22  1  0.704  0.305  0.254  1.0
  O  O23  1  0.305  0.704  0.754  1.0
  O  O24  1  0.401  0.613  0.234  1.0
  O  O25  1  0.613  0.401  0.734  1.0
[/CIF]
.