The compound described by Na4Ca2SiAs4 crystallizes in the monoclinic Cc space group. There are four inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to one Si(1), one As(1), one As(2), one As(4), and two equivalent As(3) atoms. In the second Na site, Na(2) is bonded in a 4-coordinate geometry to one As(3), one As(4), and two equivalent As(2) atoms. In the third Na site, Na(3) is bonded in a 4-coordinate geometry to one As(3), one As(4), and two equivalent As(1) atoms. In the fourth Na site, Na(4) is bonded in a 4-coordinate geometry to one As(1), one As(2), one As(3), and one As(4) atom. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 5-coordinate geometry to one As(1), one As(2), one As(4), and two equivalent As(3) atoms. In the second Ca site, Ca(2) is bonded in a 7-coordinate geometry to one Si(1), two equivalent As(1), two equivalent As(2), and two equivalent As(4) atoms. Si(1) is bonded in a distorted tetrahedral geometry to one Na(1), one Ca(2), one As(1), one As(2), one As(3), and one As(4) atom. There are four inequivalent As sites. In the first As site, As(4) is bonded in a 7-coordinate geometry to one Na(1), one Na(2), one Na(3), one Na(4), one Ca(1), two equivalent Ca(2), and one Si(1) atom. In the second As site, As(1) is bonded in a 8-coordinate geometry to one Na(1), one Na(4), two equivalent Na(3), one Ca(1), two equivalent Ca(2), and one Si(1) atom. In the third As site, As(2) is bonded in a 8-coordinate geometry to one Na(1), one Na(4), two equivalent Na(2), one Ca(1), two equivalent Ca(2), and one Si(1) atom. In the fourth As site, As(3) is bonded in a 8-coordinate geometry to one Na(2), one Na(3), one Na(4), two equivalent Na(1), two equivalent Ca(1), and one Si(1) atom. is represented by the CIF card [CIF]
data_Na4Ca2SiAs4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.450
_cell_length_b   9.450
_cell_length_c   7.166
_cell_angle_alpha   89.119
_cell_angle_beta   89.119
_cell_angle_gamma   119.510
_symmetry_Int_Tables_number   1
_cell_volume   556.685
_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  0.475  0.947  0.386  1.0
  Na  Na1  1  0.947  0.475  0.886  1.0
  Na  Na2  1  0.859  0.713  0.185  1.0
  Na  Na3  1  0.292  0.139  0.207  1.0
  Na  Na4  1  0.849  0.142  0.197  1.0
  Na  Na5  1  0.139  0.292  0.707  1.0
  Na  Na6  1  0.713  0.859  0.685  1.0
  Na  Na7  1  0.142  0.849  0.697  1.0
  Ca  Ca8  1  0.049  0.526  0.384  1.0
  Ca  Ca9  1  0.480  0.527  0.382  1.0
  Ca  Ca10  1  0.526  0.049  0.884  1.0
  Ca  Ca11  1  0.527  0.480  0.882  1.0
  Si  Si12  1  0.663  0.330  0.499  1.0
  Si  Si13  1  0.330  0.663  0.999  1.0
  As  As14  1  0.200  0.388  0.121  1.0
  As  As15  1  0.610  0.802  0.093  1.0
  As  As16  1  0.198  0.808  0.104  1.0
  As  As17  1  0.802  0.610  0.593  1.0
  As  As18  1  0.388  0.200  0.621  1.0
  As  As19  1  0.808  0.198  0.604  1.0
  As  As20  1  0.663  0.337  0.162  1.0
  As  As21  1  0.337  0.663  0.662  1.0
[/CIF]
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The compound described by Na4Ca2SiAs4 crystallizes in the monoclinic Cc space group. There are four inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to one Si(1), one As(1), one As(2), one As(4), and two equivalent As(3) atoms. In the second Na site, Na(2) is bonded in a 4-coordinate geometry to one As(3), one As(4), and two equivalent As(2) atoms. In the third Na site, Na(3) is bonded in a 4-coordinate geometry to one As(3), one As(4), and two equivalent As(1) atoms. In the fourth Na site, Na(4) is bonded in a 4-coordinate geometry to one As(1), one As(2), one As(3), and one As(4) atom. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 5-coordinate geometry to one As(1), one As(2), one As(4), and two equivalent As(3) atoms. In the second Ca site, Ca(2) is bonded in a 7-coordinate geometry to one Si(1), two equivalent As(1), two equivalent As(2), and two equivalent As(4) atoms. Si(1) is bonded in a distorted tetrahedral geometry to one Na(1), one Ca(2), one As(1), one As(2), one As(3), and one As(4) atom. There are four inequivalent As sites. In the first As site, As(4) is bonded in a 7-coordinate geometry to one Na(1), one Na(2), one Na(3), one Na(4), one Ca(1), two equivalent Ca(2), and one Si(1) atom. In the second As site, As(1) is bonded in a 8-coordinate geometry to one Na(1), one Na(4), two equivalent Na(3), one Ca(1), two equivalent Ca(2), and one Si(1) atom. In the third As site, As(2) is bonded in a 8-coordinate geometry to one Na(1), one Na(4), two equivalent Na(2), one Ca(1), two equivalent Ca(2), and one Si(1) atom. In the fourth As site, As(3) is bonded in a 8-coordinate geometry to one Na(2), one Na(3), one Na(4), two equivalent Na(1), two equivalent Ca(1), and one Si(1) atom. is represented by the CIF card [CIF]
data_Na4Ca2SiAs4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.450
_cell_length_b   9.450
_cell_length_c   7.166
_cell_angle_alpha   89.119
_cell_angle_beta   89.119
_cell_angle_gamma   119.510
_symmetry_Int_Tables_number   1
_cell_volume   556.685
_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  0.475  0.947  0.386  1.0
  Na  Na1  1  0.947  0.475  0.886  1.0
  Na  Na2  1  0.859  0.713  0.185  1.0
  Na  Na3  1  0.292  0.139  0.207  1.0
  Na  Na4  1  0.849  0.142  0.197  1.0
  Na  Na5  1  0.139  0.292  0.707  1.0
  Na  Na6  1  0.713  0.859  0.685  1.0
  Na  Na7  1  0.142  0.849  0.697  1.0
  Ca  Ca8  1  0.049  0.526  0.384  1.0
  Ca  Ca9  1  0.480  0.527  0.382  1.0
  Ca  Ca10  1  0.526  0.049  0.884  1.0
  Ca  Ca11  1  0.527  0.480  0.882  1.0
  Si  Si12  1  0.663  0.330  0.499  1.0
  Si  Si13  1  0.330  0.663  0.999  1.0
  As  As14  1  0.200  0.388  0.121  1.0
  As  As15  1  0.610  0.802  0.093  1.0
  As  As16  1  0.198  0.808  0.104  1.0
  As  As17  1  0.802  0.610  0.593  1.0
  As  As18  1  0.388  0.200  0.621  1.0
  As  As19  1  0.808  0.198  0.604  1.0
  As  As20  1  0.663  0.337  0.162  1.0
  As  As21  1  0.337  0.663  0.662  1.0
[/CIF]
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