The structure described by Na3Ca is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to eight Na(1,1) and four equivalent Ca(1) atoms to form NaNa8Ca4 cuboctahedra that share corners with four equivalent Ca(1)Na12 cuboctahedra; corners with fourteen Na(1,1)Na8Ca4 cuboctahedra; edges with six equivalent Ca(1)Na12 cuboctahedra; edges with twelve Na(1,1)Na8Ca4 cuboctahedra; faces with four equivalent Ca(1)Na12 cuboctahedra; and faces with sixteen Na(1,1)Na8Ca4 cuboctahedra. In the second Na site, Na(1) is bonded to eight Na(1,1) and four equivalent Ca(1) atoms to form NaNa8Ca4 cuboctahedra that share corners with four equivalent Ca(1)Na12 cuboctahedra; corners with fourteen Na(1,1)Na8Ca4 cuboctahedra; edges with six equivalent Ca(1)Na12 cuboctahedra; edges with twelve Na(1,1)Na8Ca4 cuboctahedra; faces with four equivalent Ca(1)Na12 cuboctahedra; and faces with sixteen Na(1,1)Na8Ca4 cuboctahedra. Ca(1) is bonded to twelve Na(1,1) atoms to form CaNa12 cuboctahedra that share corners with six equivalent Ca(1)Na12 cuboctahedra; corners with twelve equivalent Na(1)Na8Ca4 cuboctahedra; edges with eighteen Na(1,1)Na8Ca4 cuboctahedra; faces with eight equivalent Ca(1)Na12 cuboctahedra; and faces with twelve Na(1,1)Na8Ca4 cuboctahedra. is represented by the CIF card [CIF]
data_Na3Ca
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.620
_cell_length_b   7.620
_cell_length_c   6.176
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   310.540
_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  0.163  0.325  0.250  1.0
  Na  Na1  1  0.675  0.837  0.250  1.0
  Na  Na2  1  0.163  0.837  0.250  1.0
  Na  Na3  1  0.837  0.675  0.750  1.0
  Na  Na4  1  0.325  0.163  0.750  1.0
  Na  Na5  1  0.837  0.163  0.750  1.0
  Ca  Ca6  1  0.333  0.667  0.750  1.0
  Ca  Ca7  1  0.667  0.333  0.250  1.0
[/CIF]
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The structure described by Na3Ca is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to eight Na(1,1) and four equivalent Ca(1) atoms to form NaNa8Ca4 cuboctahedra that share corners with four equivalent Ca(1)Na12 cuboctahedra; corners with fourteen Na(1,1)Na8Ca4 cuboctahedra; edges with six equivalent Ca(1)Na12 cuboctahedra; edges with twelve Na(1,1)Na8Ca4 cuboctahedra; faces with four equivalent Ca(1)Na12 cuboctahedra; and faces with sixteen Na(1,1)Na8Ca4 cuboctahedra. In the second Na site, Na(1) is bonded to eight Na(1,1) and four equivalent Ca(1) atoms to form NaNa8Ca4 cuboctahedra that share corners with four equivalent Ca(1)Na12 cuboctahedra; corners with fourteen Na(1,1)Na8Ca4 cuboctahedra; edges with six equivalent Ca(1)Na12 cuboctahedra; edges with twelve Na(1,1)Na8Ca4 cuboctahedra; faces with four equivalent Ca(1)Na12 cuboctahedra; and faces with sixteen Na(1,1)Na8Ca4 cuboctahedra. Ca(1) is bonded to twelve Na(1,1) atoms to form CaNa12 cuboctahedra that share corners with six equivalent Ca(1)Na12 cuboctahedra; corners with twelve equivalent Na(1)Na8Ca4 cuboctahedra; edges with eighteen Na(1,1)Na8Ca4 cuboctahedra; faces with eight equivalent Ca(1)Na12 cuboctahedra; and faces with twelve Na(1,1)Na8Ca4 cuboctahedra. is represented by the CIF card [CIF]
data_Na3Ca
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.620
_cell_length_b   7.620
_cell_length_c   6.176
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   310.540
_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  0.163  0.325  0.250  1.0
  Na  Na1  1  0.675  0.837  0.250  1.0
  Na  Na2  1  0.163  0.837  0.250  1.0
  Na  Na3  1  0.837  0.675  0.750  1.0
  Na  Na4  1  0.325  0.163  0.750  1.0
  Na  Na5  1  0.837  0.163  0.750  1.0
  Ca  Ca6  1  0.333  0.667  0.750  1.0
  Ca  Ca7  1  0.667  0.333  0.250  1.0
[/CIF]
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