The structure described by Na4Eu2SiP4 is alpha Pu-derived structured and 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 P(1), one P(2), one P(4), and two equivalent P(3) atoms. In the second Na site, Na(2) is bonded in a 4-coordinate geometry to one P(3), one P(4), and two equivalent P(2) atoms. In the third Na site, Na(3) is bonded in a 4-coordinate geometry to one P(3), one P(4), and two equivalent P(1) atoms. In the fourth Na site, Na(4) is bonded in a 4-coordinate geometry to one P(1), one P(2), one P(3), and one P(4) atom. There are two inequivalent Eu sites. In the first Eu site, Eu(1) is bonded in a 5-coordinate geometry to one P(1), one P(2), one P(4), and two equivalent P(3) atoms. In the second Eu site, Eu(2) is bonded in a 5-coordinate geometry to one P(4), two equivalent P(1), and two equivalent P(2) atoms. Si(1) is bonded in a distorted tetrahedral geometry to one Na(1), one P(1), one P(2), one P(3), and one P(4) atom. There are four inequivalent P sites. In the first P site, P(4) is bonded in a 7-coordinate geometry to one Na(1), one Na(2), one Na(3), one Na(4), one Eu(1), one Eu(2), and one Si(1) atom. In the second P site, P(1) is bonded in a 8-coordinate geometry to one Na(1), one Na(4), two equivalent Na(3), one Eu(1), two equivalent Eu(2), and one Si(1) atom. In the third P site, P(2) is bonded in a 8-coordinate geometry to one Na(1), one Na(4), two equivalent Na(2), one Eu(1), two equivalent Eu(2), and one Si(1) atom. In the fourth P site, P(3) is bonded in a 8-coordinate geometry to one Na(2), one Na(3), one Na(4), two equivalent Na(1), two equivalent Eu(1), and one Si(1) atom. is represented by the CIF file [CIF]
data_Na4Eu2SiP4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.276
_cell_length_b   9.276
_cell_length_c   7.117
_cell_angle_alpha   89.366
_cell_angle_beta   89.366
_cell_angle_gamma   119.442
_symmetry_Int_Tables_number   1
_cell_volume   533.139
_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  0.055  0.527  0.613  1.0
  Na  Na1  1  0.527  0.055  0.113  1.0
  Na  Na2  1  0.275  0.135  0.807  1.0
  Na  Na3  1  0.869  0.718  0.786  1.0
  Na  Na4  1  0.865  0.149  0.793  1.0
  Na  Na5  1  0.718  0.869  0.286  1.0
  Na  Na6  1  0.135  0.275  0.307  1.0
  Na  Na7  1  0.149  0.865  0.293  1.0
  Eu  Eu8  1  0.470  0.949  0.616  1.0
  Eu  Eu9  1  0.467  0.520  0.615  1.0
  Eu  Eu10  1  0.949  0.470  0.116  1.0
  Eu  Eu11  1  0.520  0.467  0.115  1.0
  Si  Si12  1  0.672  0.337  0.498  1.0
  Si  Si13  1  0.337  0.672  0.998  1.0
  P  P14  1  0.607  0.798  0.888  1.0
  P  P15  1  0.198  0.395  0.908  1.0
  P  P16  1  0.193  0.799  0.899  1.0
  P  P17  1  0.395  0.198  0.408  1.0
  P  P18  1  0.798  0.607  0.388  1.0
  P  P19  1  0.799  0.193  0.399  1.0
  P  P20  1  0.663  0.340  0.825  1.0
  P  P21  1  0.340  0.663  0.325  1.0
[/CIF]
.
The structure described by Na4Eu2SiP4 is alpha Pu-derived structured and 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 P(1), one P(2), one P(4), and two equivalent P(3) atoms. In the second Na site, Na(2) is bonded in a 4-coordinate geometry to one P(3), one P(4), and two equivalent P(2) atoms. In the third Na site, Na(3) is bonded in a 4-coordinate geometry to one P(3), one P(4), and two equivalent P(1) atoms. In the fourth Na site, Na(4) is bonded in a 4-coordinate geometry to one P(1), one P(2), one P(3), and one P(4) atom. There are two inequivalent Eu sites. In the first Eu site, Eu(1) is bonded in a 5-coordinate geometry to one P(1), one P(2), one P(4), and two equivalent P(3) atoms. In the second Eu site, Eu(2) is bonded in a 5-coordinate geometry to one P(4), two equivalent P(1), and two equivalent P(2) atoms. Si(1) is bonded in a distorted tetrahedral geometry to one Na(1), one P(1), one P(2), one P(3), and one P(4) atom. There are four inequivalent P sites. In the first P site, P(4) is bonded in a 7-coordinate geometry to one Na(1), one Na(2), one Na(3), one Na(4), one Eu(1), one Eu(2), and one Si(1) atom. In the second P site, P(1) is bonded in a 8-coordinate geometry to one Na(1), one Na(4), two equivalent Na(3), one Eu(1), two equivalent Eu(2), and one Si(1) atom. In the third P site, P(2) is bonded in a 8-coordinate geometry to one Na(1), one Na(4), two equivalent Na(2), one Eu(1), two equivalent Eu(2), and one Si(1) atom. In the fourth P site, P(3) is bonded in a 8-coordinate geometry to one Na(2), one Na(3), one Na(4), two equivalent Na(1), two equivalent Eu(1), and one Si(1) atom. is represented by the CIF file [CIF]
data_Na4Eu2SiP4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.276
_cell_length_b   9.276
_cell_length_c   7.117
_cell_angle_alpha   89.366
_cell_angle_beta   89.366
_cell_angle_gamma   119.442
_symmetry_Int_Tables_number   1
_cell_volume   533.139
_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  0.055  0.527  0.613  1.0
  Na  Na1  1  0.527  0.055  0.113  1.0
  Na  Na2  1  0.275  0.135  0.807  1.0
  Na  Na3  1  0.869  0.718  0.786  1.0
  Na  Na4  1  0.865  0.149  0.793  1.0
  Na  Na5  1  0.718  0.869  0.286  1.0
  Na  Na6  1  0.135  0.275  0.307  1.0
  Na  Na7  1  0.149  0.865  0.293  1.0
  Eu  Eu8  1  0.470  0.949  0.616  1.0
  Eu  Eu9  1  0.467  0.520  0.615  1.0
  Eu  Eu10  1  0.949  0.470  0.116  1.0
  Eu  Eu11  1  0.520  0.467  0.115  1.0
  Si  Si12  1  0.672  0.337  0.498  1.0
  Si  Si13  1  0.337  0.672  0.998  1.0
  P  P14  1  0.607  0.798  0.888  1.0
  P  P15  1  0.198  0.395  0.908  1.0
  P  P16  1  0.193  0.799  0.899  1.0
  P  P17  1  0.395  0.198  0.408  1.0
  P  P18  1  0.798  0.607  0.388  1.0
  P  P19  1  0.799  0.193  0.399  1.0
  P  P20  1  0.663  0.340  0.825  1.0
  P  P21  1  0.340  0.663  0.325  1.0
[/CIF]
.