The structure described by CaNa2(SO4)2 crystallizes in the monoclinic C2/c space group. Na(1) is bonded in a 7-coordinate geometry to one O(3), one O(4), two equivalent O(2), and three equivalent O(1) atoms. Ca(1) is bonded in a 8-coordinate geometry to two equivalent O(2), two equivalent O(3), and four equivalent O(4) atoms. S(1) is bonded in a tetrahedral geometry to one O(1), one O(2), one O(3), and one O(4) atom. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to three equivalent Na(1) and one S(1) atom. In the second O site, O(2) is bonded to two equivalent Na(1), one Ca(1), and one S(1) atom to form a mixture of distorted corner and edge-sharing ONa2CaS tetrahedra. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Na(1), one Ca(1), and one S(1) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to one Na(1), two equivalent Ca(1), and one S(1) atom. is represented by the CIF file [CIF]
data_Na2Ca(SO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.618
_cell_length_b   6.618
_cell_length_c   8.700
_cell_angle_alpha   72.948
_cell_angle_beta   72.948
_cell_angle_gamma   78.326
_symmetry_Int_Tables_number   1
_cell_volume   345.386
_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  0.586  0.695  0.562  1.0
  Na  Na1  1  0.414  0.305  0.438  1.0
  Na  Na2  1  0.305  0.414  0.938  1.0
  Na  Na3  1  0.695  0.586  0.062  1.0
  Ca  Ca4  1  0.061  0.939  0.250  1.0
  Ca  Ca5  1  0.939  0.061  0.750  1.0
  S  S6  1  0.600  0.032  0.186  1.0
  S  S7  1  0.400  0.968  0.814  1.0
  S  S8  1  0.968  0.400  0.314  1.0
  S  S9  1  0.032  0.600  0.686  1.0
  O  O10  1  0.482  0.739  0.869  1.0
  O  O11  1  0.261  0.518  0.631  1.0
  O  O12  1  0.518  0.261  0.131  1.0
  O  O13  1  0.739  0.482  0.369  1.0
  O  O14  1  0.326  1.000  0.660  1.0
  O  O15  1  0.000  0.674  0.840  1.0
  O  O16  1  0.674  0.000  0.340  1.0
  O  O17  1  1.000  0.326  0.160  1.0
  O  O18  1  0.569  0.105  0.777  1.0
  O  O19  1  0.895  0.431  0.723  1.0
  O  O20  1  0.037  0.212  0.441  1.0
  O  O21  1  0.788  0.963  0.059  1.0
  O  O22  1  0.963  0.788  0.559  1.0
  O  O23  1  0.212  0.037  0.941  1.0
  O  O24  1  0.105  0.569  0.277  1.0
  O  O25  1  0.431  0.895  0.223  1.0
[/CIF]
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The structure described by CaNa2(SO4)2 crystallizes in the monoclinic C2/c space group. Na(1) is bonded in a 7-coordinate geometry to one O(3), one O(4), two equivalent O(2), and three equivalent O(1) atoms. Ca(1) is bonded in a 8-coordinate geometry to two equivalent O(2), two equivalent O(3), and four equivalent O(4) atoms. S(1) is bonded in a tetrahedral geometry to one O(1), one O(2), one O(3), and one O(4) atom. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to three equivalent Na(1) and one S(1) atom. In the second O site, O(2) is bonded to two equivalent Na(1), one Ca(1), and one S(1) atom to form a mixture of distorted corner and edge-sharing ONa2CaS tetrahedra. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Na(1), one Ca(1), and one S(1) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to one Na(1), two equivalent Ca(1), and one S(1) atom. is represented by the CIF file [CIF]
data_Na2Ca(SO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.618
_cell_length_b   6.618
_cell_length_c   8.700
_cell_angle_alpha   72.948
_cell_angle_beta   72.948
_cell_angle_gamma   78.326
_symmetry_Int_Tables_number   1
_cell_volume   345.386
_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  0.586  0.695  0.562  1.0
  Na  Na1  1  0.414  0.305  0.438  1.0
  Na  Na2  1  0.305  0.414  0.938  1.0
  Na  Na3  1  0.695  0.586  0.062  1.0
  Ca  Ca4  1  0.061  0.939  0.250  1.0
  Ca  Ca5  1  0.939  0.061  0.750  1.0
  S  S6  1  0.600  0.032  0.186  1.0
  S  S7  1  0.400  0.968  0.814  1.0
  S  S8  1  0.968  0.400  0.314  1.0
  S  S9  1  0.032  0.600  0.686  1.0
  O  O10  1  0.482  0.739  0.869  1.0
  O  O11  1  0.261  0.518  0.631  1.0
  O  O12  1  0.518  0.261  0.131  1.0
  O  O13  1  0.739  0.482  0.369  1.0
  O  O14  1  0.326  1.000  0.660  1.0
  O  O15  1  0.000  0.674  0.840  1.0
  O  O16  1  0.674  0.000  0.340  1.0
  O  O17  1  1.000  0.326  0.160  1.0
  O  O18  1  0.569  0.105  0.777  1.0
  O  O19  1  0.895  0.431  0.723  1.0
  O  O20  1  0.037  0.212  0.441  1.0
  O  O21  1  0.788  0.963  0.059  1.0
  O  O22  1  0.963  0.788  0.559  1.0
  O  O23  1  0.212  0.037  0.941  1.0
  O  O24  1  0.105  0.569  0.277  1.0
  O  O25  1  0.431  0.895  0.223  1.0
[/CIF]
.