The compound described by Na4SiSe4 crystallizes in the orthorhombic Pnma space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded in a distorted square co-planar geometry to two equivalent Se(1) and two equivalent Se(3) atoms. In the second Na site, Na(2) is bonded in a distorted pentagonal planar geometry to one Se(2) and four equivalent Se(1) atoms. In the third Na site, Na(3) is bonded in a 6-coordinate geometry to one Si(1), one Se(3), two equivalent Se(1), and two equivalent Se(2) atoms. Si(1) is bonded to two equivalent Na(3), one Se(2), one Se(3), and two equivalent Se(1) atoms to form SiNa2Se4 tetrahedra that share corners with four equivalent Se(1)Na5Si octahedra and corners with two equivalent Se(3)Na4Si trigonal bipyramids. The corner-sharing octahedral tilt angles range from 64-137°. There are three inequivalent Se sites. In the first Se site, Se(3) is bonded to two equivalent Na(1), two equivalent Na(3), and one Si(1) atom to form distorted SeNa4Si trigonal bipyramids that share corners with six equivalent Se(1)Na5Si octahedra, corners with two equivalent Si(1)Na2Se4 tetrahedra, corners with two equivalent Se(3)Na4Si trigonal bipyramids, and edges with two equivalent Se(1)Na5Si octahedra. The corner-sharing octahedral tilt angles range from 76-80°. In the second Se site, Se(1) is bonded to one Na(1), two equivalent Na(2), two equivalent Na(3), and one Si(1) atom to form distorted SeNa5Si octahedra that share corners with six equivalent Se(1)Na5Si octahedra, corners with two equivalent Si(1)Na2Se4 tetrahedra, corners with three equivalent Se(3)Na4Si trigonal bipyramids, edges with two equivalent Se(1)Na5Si octahedra, and  an edgeedge with one Se(3)Na4Si trigonal bipyramid. The corner-sharing octahedral tilt angles range from 0-54°. In the third Se site, Se(2) is bonded in a 6-coordinate geometry to one Na(2), four equivalent Na(3), and one Si(1) atom. is represented by the CIF card [CIF]
data_Na4SiSe4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.158
_cell_length_b   9.115
_cell_length_c   14.287
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   932.143
_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  0.000  0.000  0.000  1.0
  Na  Na1  1  0.500  0.000  0.500  1.0
  Na  Na2  1  0.000  0.500  0.000  1.0
  Na  Na3  1  0.500  0.500  0.500  1.0
  Na  Na4  1  0.994  0.750  0.454  1.0
  Na  Na5  1  0.494  0.250  0.046  1.0
  Na  Na6  1  0.006  0.250  0.546  1.0
  Na  Na7  1  0.506  0.750  0.954  1.0
  Na  Na8  1  0.863  0.051  0.266  1.0
  Na  Na9  1  0.363  0.949  0.234  1.0
  Na  Na10  1  0.137  0.551  0.734  1.0
  Na  Na11  1  0.637  0.449  0.766  1.0
  Na  Na12  1  0.137  0.949  0.734  1.0
  Na  Na13  1  0.637  0.051  0.766  1.0
  Na  Na14  1  0.863  0.449  0.266  1.0
  Na  Na15  1  0.363  0.551  0.234  1.0
  Si  Si16  1  0.778  0.750  0.165  1.0
  Si  Si17  1  0.278  0.250  0.335  1.0
  Si  Si18  1  0.222  0.250  0.835  1.0
  Si  Si19  1  0.722  0.750  0.665  1.0
  Se  Se20  1  0.657  0.547  0.096  1.0
  Se  Se21  1  0.157  0.453  0.404  1.0
  Se  Se22  1  0.343  0.047  0.904  1.0
  Se  Se23  1  0.843  0.953  0.596  1.0
  Se  Se24  1  0.343  0.453  0.904  1.0
  Se  Se25  1  0.843  0.547  0.596  1.0
  Se  Se26  1  0.657  0.953  0.096  1.0
  Se  Se27  1  0.157  0.047  0.404  1.0
  Se  Se28  1  0.682  0.750  0.318  1.0
  Se  Se29  1  0.182  0.250  0.182  1.0
  Se  Se30  1  0.318  0.250  0.682  1.0
  Se  Se31  1  0.818  0.750  0.818  1.0
  Se  Se32  1  0.093  0.750  0.141  1.0
  Se  Se33  1  0.593  0.250  0.359  1.0
  Se  Se34  1  0.907  0.250  0.859  1.0
  Se  Se35  1  0.407  0.750  0.641  1.0
[/CIF]
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The compound described by Na4SiSe4 crystallizes in the orthorhombic Pnma space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded in a distorted square co-planar geometry to two equivalent Se(1) and two equivalent Se(3) atoms. In the second Na site, Na(2) is bonded in a distorted pentagonal planar geometry to one Se(2) and four equivalent Se(1) atoms. In the third Na site, Na(3) is bonded in a 6-coordinate geometry to one Si(1), one Se(3), two equivalent Se(1), and two equivalent Se(2) atoms. Si(1) is bonded to two equivalent Na(3), one Se(2), one Se(3), and two equivalent Se(1) atoms to form SiNa2Se4 tetrahedra that share corners with four equivalent Se(1)Na5Si octahedra and corners with two equivalent Se(3)Na4Si trigonal bipyramids. The corner-sharing octahedral tilt angles range from 64-137°. There are three inequivalent Se sites. In the first Se site, Se(3) is bonded to two equivalent Na(1), two equivalent Na(3), and one Si(1) atom to form distorted SeNa4Si trigonal bipyramids that share corners with six equivalent Se(1)Na5Si octahedra, corners with two equivalent Si(1)Na2Se4 tetrahedra, corners with two equivalent Se(3)Na4Si trigonal bipyramids, and edges with two equivalent Se(1)Na5Si octahedra. The corner-sharing octahedral tilt angles range from 76-80°. In the second Se site, Se(1) is bonded to one Na(1), two equivalent Na(2), two equivalent Na(3), and one Si(1) atom to form distorted SeNa5Si octahedra that share corners with six equivalent Se(1)Na5Si octahedra, corners with two equivalent Si(1)Na2Se4 tetrahedra, corners with three equivalent Se(3)Na4Si trigonal bipyramids, edges with two equivalent Se(1)Na5Si octahedra, and  an edgeedge with one Se(3)Na4Si trigonal bipyramid. The corner-sharing octahedral tilt angles range from 0-54°. In the third Se site, Se(2) is bonded in a 6-coordinate geometry to one Na(2), four equivalent Na(3), and one Si(1) atom. is represented by the CIF card [CIF]
data_Na4SiSe4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.158
_cell_length_b   9.115
_cell_length_c   14.287
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   932.143
_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  0.000  0.000  0.000  1.0
  Na  Na1  1  0.500  0.000  0.500  1.0
  Na  Na2  1  0.000  0.500  0.000  1.0
  Na  Na3  1  0.500  0.500  0.500  1.0
  Na  Na4  1  0.994  0.750  0.454  1.0
  Na  Na5  1  0.494  0.250  0.046  1.0
  Na  Na6  1  0.006  0.250  0.546  1.0
  Na  Na7  1  0.506  0.750  0.954  1.0
  Na  Na8  1  0.863  0.051  0.266  1.0
  Na  Na9  1  0.363  0.949  0.234  1.0
  Na  Na10  1  0.137  0.551  0.734  1.0
  Na  Na11  1  0.637  0.449  0.766  1.0
  Na  Na12  1  0.137  0.949  0.734  1.0
  Na  Na13  1  0.637  0.051  0.766  1.0
  Na  Na14  1  0.863  0.449  0.266  1.0
  Na  Na15  1  0.363  0.551  0.234  1.0
  Si  Si16  1  0.778  0.750  0.165  1.0
  Si  Si17  1  0.278  0.250  0.335  1.0
  Si  Si18  1  0.222  0.250  0.835  1.0
  Si  Si19  1  0.722  0.750  0.665  1.0
  Se  Se20  1  0.657  0.547  0.096  1.0
  Se  Se21  1  0.157  0.453  0.404  1.0
  Se  Se22  1  0.343  0.047  0.904  1.0
  Se  Se23  1  0.843  0.953  0.596  1.0
  Se  Se24  1  0.343  0.453  0.904  1.0
  Se  Se25  1  0.843  0.547  0.596  1.0
  Se  Se26  1  0.657  0.953  0.096  1.0
  Se  Se27  1  0.157  0.047  0.404  1.0
  Se  Se28  1  0.682  0.750  0.318  1.0
  Se  Se29  1  0.182  0.250  0.182  1.0
  Se  Se30  1  0.318  0.250  0.682  1.0
  Se  Se31  1  0.818  0.750  0.818  1.0
  Se  Se32  1  0.093  0.750  0.141  1.0
  Se  Se33  1  0.593  0.250  0.359  1.0
  Se  Se34  1  0.907  0.250  0.859  1.0
  Se  Se35  1  0.407  0.750  0.641  1.0
[/CIF]
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