The material described by Na2Zn2Se3 crystallizes in the monoclinic C2/c space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded to two equivalent Se(2) and four equivalent Se(1) atoms to form NaSe6 octahedra that share corners with two equivalent Zn(1)Se4 tetrahedra, corners with four equivalent Zn(2)Se4 tetrahedra, edges with two equivalent Na(1)Se6 octahedra, edges with three equivalent Na(2)Se6 octahedra, edges with two equivalent Zn(2)Se4 tetrahedra, and edges with four equivalent Zn(1)Se4 tetrahedra. In the second Na site, Na(2) is bonded to two equivalent Se(1), two equivalent Se(2), and two equivalent Se(3) atoms to form distorted NaSe6 octahedra that share corners with four equivalent Zn(1)Se4 tetrahedra, corners with four equivalent Zn(2)Se4 tetrahedra, edges with three equivalent Na(1)Se6 octahedra, edges with two equivalent Zn(1)Se4 tetrahedra, and edges with two equivalent Zn(2)Se4 tetrahedra. In the third Na site, Na(3) is bonded in a 4-coordinate geometry to one Se(1), one Se(2), and three equivalent Se(3) atoms. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded to one Se(2), one Se(3), and two equivalent Se(1) atoms to form ZnSe4 tetrahedra that share  a cornercorner with one Na(1)Se6 octahedra, corners with two equivalent Na(2)Se6 octahedra, corners with two equivalent Zn(1)Se4 tetrahedra, corners with three equivalent Zn(2)Se4 tetrahedra,  an edgeedge with one Na(2)Se6 octahedra, edges with two equivalent Na(1)Se6 octahedra, and  an edgeedge with one Zn(2)Se4 tetrahedra. The corner-sharing octahedral tilt angles range from 22-52°. In the second Zn site, Zn(2) is bonded to one Se(1), one Se(3), and two equivalent Se(2) atoms to form ZnSe4 tetrahedra that share corners with two equivalent Na(1)Se6 octahedra, corners with two equivalent Na(2)Se6 octahedra, corners with three equivalent Zn(1)Se4 tetrahedra,  an edgeedge with one Na(1)Se6 octahedra,  an edgeedge with one Na(2)Se6 octahedra,  an edgeedge with one Zn(1)Se4 tetrahedra, and  an edgeedge with one Zn(2)Se4 tetrahedra. The corner-sharing octahedral tilt angles range from 23-55°. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded in a 7-coordinate geometry to one Na(2), one Na(3), two equivalent Na(1), one Zn(2), and two equivalent Zn(1) atoms. In the second Se site, Se(2) is bonded to one Na(1), one Na(2), one Na(3), one Zn(1), and two equivalent Zn(2) atoms to form distorted SeNa3Zn3 pentagonal pyramids that share corners with two equivalent Se(2)Na3Zn3 pentagonal pyramids, corners with two equivalent Se(3)Na4Zn2 pentagonal pyramids,  an edgeedge with one Se(2)Na3Zn3 pentagonal pyramid, and edges with three equivalent Se(3)Na4Zn2 pentagonal pyramids. In the third Se site, Se(3) is bonded to one Na(2), three equivalent Na(3), one Zn(1), and one Zn(2) atom to form distorted SeNa4Zn2 pentagonal pyramids that share corners with two equivalent Se(2)Na3Zn3 pentagonal pyramids, corners with two equivalent Se(3)Na4Zn2 pentagonal pyramids,  an edgeedge with one Se(3)Na4Zn2 pentagonal pyramid, edges with three equivalent Se(2)Na3Zn3 pentagonal pyramids, and  a faceface with one Se(3)Na4Zn2 pentagonal pyramid. is represented by the Crystallographic Information File (CIF) [CIF]
data_Na2Zn2Se3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.235
_cell_length_b   10.235
_cell_length_c   6.998
_cell_angle_alpha   70.195
_cell_angle_beta   70.195
_cell_angle_gamma   83.645
_symmetry_Int_Tables_number   1
_cell_volume   648.951
_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  0.433  0.567  0.750  1.0
  Na  Na1  1  0.567  0.433  0.250  1.0
  Na  Na2  1  0.718  0.282  0.750  1.0
  Na  Na3  1  0.282  0.718  0.250  1.0
  Na  Na4  1  0.807  0.977  0.640  1.0
  Na  Na5  1  0.023  0.193  0.860  1.0
  Na  Na6  1  0.193  0.023  0.360  1.0
  Na  Na7  1  0.977  0.807  0.140  1.0
  Zn  Zn8  1  0.363  0.208  0.797  1.0
  Zn  Zn9  1  0.792  0.637  0.703  1.0
  Zn  Zn10  1  0.637  0.792  0.203  1.0
  Zn  Zn11  1  0.208  0.363  0.297  1.0
  Zn  Zn12  1  0.081  0.549  0.761  1.0
  Zn  Zn13  1  0.451  0.919  0.739  1.0
  Zn  Zn14  1  0.919  0.451  0.239  1.0
  Zn  Zn15  1  0.549  0.081  0.261  1.0
  Se  Se16  1  0.274  0.423  0.571  1.0
  Se  Se17  1  0.577  0.726  0.929  1.0
  Se  Se18  1  0.726  0.577  0.429  1.0
  Se  Se19  1  0.423  0.274  0.071  1.0
  Se  Se20  1  0.582  0.149  0.551  1.0
  Se  Se21  1  0.851  0.418  0.949  1.0
  Se  Se22  1  0.418  0.851  0.449  1.0
  Se  Se23  1  0.149  0.582  0.051  1.0
  Se  Se24  1  0.007  0.771  0.557  1.0
  Se  Se25  1  0.229  0.993  0.943  1.0
  Se  Se26  1  0.993  0.229  0.443  1.0
  Se  Se27  1  0.771  0.007  0.057  1.0
[/CIF]
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The material described by Na2Zn2Se3 crystallizes in the monoclinic C2/c space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded to two equivalent Se(2) and four equivalent Se(1) atoms to form NaSe6 octahedra that share corners with two equivalent Zn(1)Se4 tetrahedra, corners with four equivalent Zn(2)Se4 tetrahedra, edges with two equivalent Na(1)Se6 octahedra, edges with three equivalent Na(2)Se6 octahedra, edges with two equivalent Zn(2)Se4 tetrahedra, and edges with four equivalent Zn(1)Se4 tetrahedra. In the second Na site, Na(2) is bonded to two equivalent Se(1), two equivalent Se(2), and two equivalent Se(3) atoms to form distorted NaSe6 octahedra that share corners with four equivalent Zn(1)Se4 tetrahedra, corners with four equivalent Zn(2)Se4 tetrahedra, edges with three equivalent Na(1)Se6 octahedra, edges with two equivalent Zn(1)Se4 tetrahedra, and edges with two equivalent Zn(2)Se4 tetrahedra. In the third Na site, Na(3) is bonded in a 4-coordinate geometry to one Se(1), one Se(2), and three equivalent Se(3) atoms. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded to one Se(2), one Se(3), and two equivalent Se(1) atoms to form ZnSe4 tetrahedra that share  a cornercorner with one Na(1)Se6 octahedra, corners with two equivalent Na(2)Se6 octahedra, corners with two equivalent Zn(1)Se4 tetrahedra, corners with three equivalent Zn(2)Se4 tetrahedra,  an edgeedge with one Na(2)Se6 octahedra, edges with two equivalent Na(1)Se6 octahedra, and  an edgeedge with one Zn(2)Se4 tetrahedra. The corner-sharing octahedral tilt angles range from 22-52°. In the second Zn site, Zn(2) is bonded to one Se(1), one Se(3), and two equivalent Se(2) atoms to form ZnSe4 tetrahedra that share corners with two equivalent Na(1)Se6 octahedra, corners with two equivalent Na(2)Se6 octahedra, corners with three equivalent Zn(1)Se4 tetrahedra,  an edgeedge with one Na(1)Se6 octahedra,  an edgeedge with one Na(2)Se6 octahedra,  an edgeedge with one Zn(1)Se4 tetrahedra, and  an edgeedge with one Zn(2)Se4 tetrahedra. The corner-sharing octahedral tilt angles range from 23-55°. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded in a 7-coordinate geometry to one Na(2), one Na(3), two equivalent Na(1), one Zn(2), and two equivalent Zn(1) atoms. In the second Se site, Se(2) is bonded to one Na(1), one Na(2), one Na(3), one Zn(1), and two equivalent Zn(2) atoms to form distorted SeNa3Zn3 pentagonal pyramids that share corners with two equivalent Se(2)Na3Zn3 pentagonal pyramids, corners with two equivalent Se(3)Na4Zn2 pentagonal pyramids,  an edgeedge with one Se(2)Na3Zn3 pentagonal pyramid, and edges with three equivalent Se(3)Na4Zn2 pentagonal pyramids. In the third Se site, Se(3) is bonded to one Na(2), three equivalent Na(3), one Zn(1), and one Zn(2) atom to form distorted SeNa4Zn2 pentagonal pyramids that share corners with two equivalent Se(2)Na3Zn3 pentagonal pyramids, corners with two equivalent Se(3)Na4Zn2 pentagonal pyramids,  an edgeedge with one Se(3)Na4Zn2 pentagonal pyramid, edges with three equivalent Se(2)Na3Zn3 pentagonal pyramids, and  a faceface with one Se(3)Na4Zn2 pentagonal pyramid. is represented by the Crystallographic Information File (CIF) [CIF]
data_Na2Zn2Se3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.235
_cell_length_b   10.235
_cell_length_c   6.998
_cell_angle_alpha   70.195
_cell_angle_beta   70.195
_cell_angle_gamma   83.645
_symmetry_Int_Tables_number   1
_cell_volume   648.951
_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  0.433  0.567  0.750  1.0
  Na  Na1  1  0.567  0.433  0.250  1.0
  Na  Na2  1  0.718  0.282  0.750  1.0
  Na  Na3  1  0.282  0.718  0.250  1.0
  Na  Na4  1  0.807  0.977  0.640  1.0
  Na  Na5  1  0.023  0.193  0.860  1.0
  Na  Na6  1  0.193  0.023  0.360  1.0
  Na  Na7  1  0.977  0.807  0.140  1.0
  Zn  Zn8  1  0.363  0.208  0.797  1.0
  Zn  Zn9  1  0.792  0.637  0.703  1.0
  Zn  Zn10  1  0.637  0.792  0.203  1.0
  Zn  Zn11  1  0.208  0.363  0.297  1.0
  Zn  Zn12  1  0.081  0.549  0.761  1.0
  Zn  Zn13  1  0.451  0.919  0.739  1.0
  Zn  Zn14  1  0.919  0.451  0.239  1.0
  Zn  Zn15  1  0.549  0.081  0.261  1.0
  Se  Se16  1  0.274  0.423  0.571  1.0
  Se  Se17  1  0.577  0.726  0.929  1.0
  Se  Se18  1  0.726  0.577  0.429  1.0
  Se  Se19  1  0.423  0.274  0.071  1.0
  Se  Se20  1  0.582  0.149  0.551  1.0
  Se  Se21  1  0.851  0.418  0.949  1.0
  Se  Se22  1  0.418  0.851  0.449  1.0
  Se  Se23  1  0.149  0.582  0.051  1.0
  Se  Se24  1  0.007  0.771  0.557  1.0
  Se  Se25  1  0.229  0.993  0.943  1.0
  Se  Se26  1  0.993  0.229  0.443  1.0
  Se  Se27  1  0.771  0.007  0.057  1.0
[/CIF]
.