The compound described by Na2AsO8 crystallizes in the orthorhombic P2_12_12 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a distorted rectangular see-saw-like geometry to one O(1), one O(3), and two equivalent O(5) atoms. In the second Na site, Na(2) is bonded in a 3-coordinate geometry to one O(2), one O(6), one O(7), one O(8), one O(9), and two equivalent O(1) atoms. As(1) is bonded in a tetrahedral geometry to one O(1), one O(3), one O(5), and one O(7) atom. There are nine inequivalent O sites. In the first O site, O(6) is bonded in a distorted bent 120 degrees geometry to one Na(2) and one O(4) atom. In the second O site, O(7) is bonded in a 3-coordinate geometry to one Na(2), one As(1), and one O(9) atom. In the third O site, O(8) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Na(2) and two equivalent O(2) atoms. In the fourth O site, O(9) is bonded in a 4-coordinate geometry to two equivalent Na(2) and two equivalent O(7) atoms. In the fifth O site, O(1) is bonded in a 4-coordinate geometry to one Na(1), two equivalent Na(2), and one As(1) atom. In the sixth O site, O(2) is bonded in a distorted bent 120 degrees geometry to one Na(2) and one O(8) atom. In the seventh O site, O(3) is bonded in a bent 150 degrees geometry to one Na(1) and one As(1) atom. In the eighth O site, O(4) is bonded in a single-bond geometry to one O(6) atom. In the ninth O site, O(5) is bonded in a 3-coordinate geometry to two equivalent Na(1) and one As(1) atom. is represented by the CIF file [CIF]
data_Na2AsO8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.065
_cell_length_b   5.756
_cell_length_c   17.769
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   722.581
_cell_formula_units_Z   4
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  0.611  0.905  0.790  1.0
  Na  Na1  1  0.389  0.905  0.210  1.0
  Na  Na2  1  0.111  0.095  0.710  1.0
  Na  Na3  1  0.889  0.095  0.290  1.0
  Na  Na4  1  0.805  0.795  0.538  1.0
  Na  Na5  1  0.195  0.795  0.462  1.0
  Na  Na6  1  0.305  0.205  0.962  1.0
  Na  Na7  1  0.695  0.205  0.038  1.0
  As  As8  1  0.282  0.657  0.633  1.0
  As  As9  1  0.718  0.657  0.367  1.0
  As  As10  1  0.782  0.343  0.867  1.0
  As  As11  1  0.218  0.343  0.133  1.0
  O  O12  1  0.095  0.795  0.592  1.0
  O  O13  1  0.905  0.795  0.408  1.0
  O  O14  1  0.595  0.205  0.908  1.0
  O  O15  1  0.405  0.205  0.092  1.0
  O  O16  1  0.158  0.309  0.498  1.0
  O  O17  1  0.842  0.309  0.502  1.0
  O  O18  1  0.658  0.691  0.002  1.0
  O  O19  1  0.342  0.691  0.998  1.0
  O  O20  1  0.264  0.367  0.641  1.0
  O  O21  1  0.736  0.367  0.359  1.0
  O  O22  1  0.764  0.633  0.859  1.0
  O  O23  1  0.236  0.633  0.141  1.0
  O  O24  1  0.692  0.237  0.646  1.0
  O  O25  1  0.308  0.237  0.354  1.0
  O  O26  1  0.192  0.763  0.854  1.0
  O  O27  1  0.808  0.763  0.146  1.0
  O  O28  1  0.866  0.187  0.793  1.0
  O  O29  1  0.134  0.187  0.207  1.0
  O  O30  1  0.366  0.813  0.707  1.0
  O  O31  1  0.634  0.813  0.293  1.0
  O  O32  1  0.751  0.435  0.658  1.0
  O  O33  1  0.249  0.435  0.342  1.0
  O  O34  1  0.251  0.565  0.842  1.0
  O  O35  1  0.749  0.565  0.158  1.0
  O  O36  1  0.493  0.715  0.566  1.0
  O  O37  1  0.507  0.715  0.434  1.0
  O  O38  1  0.993  0.285  0.934  1.0
  O  O39  1  0.007  0.285  0.066  1.0
  O  O40  1  0.000  0.194  0.500  1.0
  O  O41  1  0.500  0.806  0.000  1.0
  O  O42  1  0.500  0.560  0.500  1.0
  O  O43  1  0.000  0.440  0.000  1.0
[/CIF]
.
The compound described by Na2AsO8 crystallizes in the orthorhombic P2_12_12 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a distorted rectangular see-saw-like geometry to one O(1), one O(3), and two equivalent O(5) atoms. In the second Na site, Na(2) is bonded in a 3-coordinate geometry to one O(2), one O(6), one O(7), one O(8), one O(9), and two equivalent O(1) atoms. As(1) is bonded in a tetrahedral geometry to one O(1), one O(3), one O(5), and one O(7) atom. There are nine inequivalent O sites. In the first O site, O(6) is bonded in a distorted bent 120 degrees geometry to one Na(2) and one O(4) atom. In the second O site, O(7) is bonded in a 3-coordinate geometry to one Na(2), one As(1), and one O(9) atom. In the third O site, O(8) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Na(2) and two equivalent O(2) atoms. In the fourth O site, O(9) is bonded in a 4-coordinate geometry to two equivalent Na(2) and two equivalent O(7) atoms. In the fifth O site, O(1) is bonded in a 4-coordinate geometry to one Na(1), two equivalent Na(2), and one As(1) atom. In the sixth O site, O(2) is bonded in a distorted bent 120 degrees geometry to one Na(2) and one O(8) atom. In the seventh O site, O(3) is bonded in a bent 150 degrees geometry to one Na(1) and one As(1) atom. In the eighth O site, O(4) is bonded in a single-bond geometry to one O(6) atom. In the ninth O site, O(5) is bonded in a 3-coordinate geometry to two equivalent Na(1) and one As(1) atom. is represented by the CIF file [CIF]
data_Na2AsO8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.065
_cell_length_b   5.756
_cell_length_c   17.769
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   722.581
_cell_formula_units_Z   4
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  0.611  0.905  0.790  1.0
  Na  Na1  1  0.389  0.905  0.210  1.0
  Na  Na2  1  0.111  0.095  0.710  1.0
  Na  Na3  1  0.889  0.095  0.290  1.0
  Na  Na4  1  0.805  0.795  0.538  1.0
  Na  Na5  1  0.195  0.795  0.462  1.0
  Na  Na6  1  0.305  0.205  0.962  1.0
  Na  Na7  1  0.695  0.205  0.038  1.0
  As  As8  1  0.282  0.657  0.633  1.0
  As  As9  1  0.718  0.657  0.367  1.0
  As  As10  1  0.782  0.343  0.867  1.0
  As  As11  1  0.218  0.343  0.133  1.0
  O  O12  1  0.095  0.795  0.592  1.0
  O  O13  1  0.905  0.795  0.408  1.0
  O  O14  1  0.595  0.205  0.908  1.0
  O  O15  1  0.405  0.205  0.092  1.0
  O  O16  1  0.158  0.309  0.498  1.0
  O  O17  1  0.842  0.309  0.502  1.0
  O  O18  1  0.658  0.691  0.002  1.0
  O  O19  1  0.342  0.691  0.998  1.0
  O  O20  1  0.264  0.367  0.641  1.0
  O  O21  1  0.736  0.367  0.359  1.0
  O  O22  1  0.764  0.633  0.859  1.0
  O  O23  1  0.236  0.633  0.141  1.0
  O  O24  1  0.692  0.237  0.646  1.0
  O  O25  1  0.308  0.237  0.354  1.0
  O  O26  1  0.192  0.763  0.854  1.0
  O  O27  1  0.808  0.763  0.146  1.0
  O  O28  1  0.866  0.187  0.793  1.0
  O  O29  1  0.134  0.187  0.207  1.0
  O  O30  1  0.366  0.813  0.707  1.0
  O  O31  1  0.634  0.813  0.293  1.0
  O  O32  1  0.751  0.435  0.658  1.0
  O  O33  1  0.249  0.435  0.342  1.0
  O  O34  1  0.251  0.565  0.842  1.0
  O  O35  1  0.749  0.565  0.158  1.0
  O  O36  1  0.493  0.715  0.566  1.0
  O  O37  1  0.507  0.715  0.434  1.0
  O  O38  1  0.993  0.285  0.934  1.0
  O  O39  1  0.007  0.285  0.066  1.0
  O  O40  1  0.000  0.194  0.500  1.0
  O  O41  1  0.500  0.806  0.000  1.0
  O  O42  1  0.500  0.560  0.500  1.0
  O  O43  1  0.000  0.440  0.000  1.0
[/CIF]
.