The crystal structure described by Cr4N2Se3 crystallizes in the orthorhombic Pnma space group. There are three inequivalent Cr sites. In the first Cr site, Cr(1) is bonded in a distorted L-shaped geometry to two equivalent N(1) and four equivalent Se(2) atoms. In the second Cr site, Cr(2) is bonded to two equivalent N(1) and two equivalent Se(1) atoms to form distorted CrSe2N2 tetrahedra that share corners with eight equivalent Cr(3)Se4N2 octahedra and corners with two equivalent Cr(2)Se2N2 tetrahedra. The corner-sharing octahedral tilt angles range from 52-82°. In the third Cr site, Cr(3) is bonded to two equivalent N(1), one Se(1), and three equivalent Se(2) atoms to form distorted CrSe4N2 octahedra that share corners with five equivalent Cr(3)Se4N2 octahedra, corners with four equivalent Cr(2)Se2N2 tetrahedra, and edges with two equivalent Cr(3)Se4N2 octahedra. The corner-sharing octahedral tilt angles range from 56-66°. N(1) is bonded to one Cr(1), one Cr(2), and two equivalent Cr(3) atoms to form distorted NCr4 trigonal pyramids that share corners with four equivalent Se(1)Cr4 tetrahedra, corners with six equivalent Se(2)Cr5 trigonal bipyramids, edges with two equivalent Se(2)Cr5 trigonal bipyramids, and edges with two equivalent N(1)Cr4 trigonal pyramids. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded to two equivalent Cr(2) and two equivalent Cr(3) atoms to form distorted SeCr4 tetrahedra that share corners with two equivalent Se(1)Cr4 tetrahedra, corners with six equivalent Se(2)Cr5 trigonal bipyramids, and corners with eight equivalent N(1)Cr4 trigonal pyramids. In the second Se site, Se(2) is bonded to two equivalent Cr(1) and three equivalent Cr(3) atoms to form distorted SeCr5 trigonal bipyramids that share corners with three equivalent Se(1)Cr4 tetrahedra, corners with four equivalent Se(2)Cr5 trigonal bipyramids, corners with six equivalent N(1)Cr4 trigonal pyramids, edges with four equivalent Se(2)Cr5 trigonal bipyramids, and edges with two equivalent N(1)Cr4 trigonal pyramids. is represented by the CIF file [CIF]
data_Cr4Se3N2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.077
_cell_length_b   10.399
_cell_length_c   9.210
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   582.002
_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
  Cr  Cr0  1  0.579  0.250  0.867  1.0
  Cr  Cr1  1  0.079  0.250  0.633  1.0
  Cr  Cr2  1  0.421  0.750  0.133  1.0
  Cr  Cr3  1  0.921  0.750  0.367  1.0
  Cr  Cr4  1  0.795  0.250  0.400  1.0
  Cr  Cr5  1  0.295  0.250  0.100  1.0
  Cr  Cr6  1  0.205  0.750  0.600  1.0
  Cr  Cr7  1  0.705  0.750  0.900  1.0
  Cr  Cr8  1  0.709  0.473  0.073  1.0
  Cr  Cr9  1  0.209  0.027  0.427  1.0
  Cr  Cr10  1  0.291  0.973  0.927  1.0
  Cr  Cr11  1  0.791  0.527  0.573  1.0
  Cr  Cr12  1  0.291  0.527  0.927  1.0
  Cr  Cr13  1  0.791  0.973  0.573  1.0
  Cr  Cr14  1  0.709  0.027  0.073  1.0
  Cr  Cr15  1  0.209  0.473  0.427  1.0
  Se  Se16  1  0.889  0.250  0.144  1.0
  Se  Se17  1  0.389  0.250  0.356  1.0
  Se  Se18  1  0.111  0.750  0.856  1.0
  Se  Se19  1  0.611  0.750  0.644  1.0
  Se  Se20  1  0.585  0.570  0.324  1.0
  Se  Se21  1  0.085  0.930  0.176  1.0
  Se  Se22  1  0.415  0.070  0.676  1.0
  Se  Se23  1  0.915  0.430  0.824  1.0
  Se  Se24  1  0.415  0.430  0.676  1.0
  Se  Se25  1  0.915  0.070  0.824  1.0
  Se  Se26  1  0.585  0.930  0.324  1.0
  Se  Se27  1  0.085  0.570  0.176  1.0
  N  N28  1  0.554  0.623  0.995  1.0
  N  N29  1  0.054  0.877  0.505  1.0
  N  N30  1  0.446  0.123  0.005  1.0
  N  N31  1  0.946  0.377  0.495  1.0
  N  N32  1  0.446  0.377  0.005  1.0
  N  N33  1  0.946  0.123  0.495  1.0
  N  N34  1  0.554  0.877  0.995  1.0
  N  N35  1  0.054  0.623  0.505  1.0
[/CIF]
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The crystal structure described by Cr4N2Se3 crystallizes in the orthorhombic Pnma space group. There are three inequivalent Cr sites. In the first Cr site, Cr(1) is bonded in a distorted L-shaped geometry to two equivalent N(1) and four equivalent Se(2) atoms. In the second Cr site, Cr(2) is bonded to two equivalent N(1) and two equivalent Se(1) atoms to form distorted CrSe2N2 tetrahedra that share corners with eight equivalent Cr(3)Se4N2 octahedra and corners with two equivalent Cr(2)Se2N2 tetrahedra. The corner-sharing octahedral tilt angles range from 52-82°. In the third Cr site, Cr(3) is bonded to two equivalent N(1), one Se(1), and three equivalent Se(2) atoms to form distorted CrSe4N2 octahedra that share corners with five equivalent Cr(3)Se4N2 octahedra, corners with four equivalent Cr(2)Se2N2 tetrahedra, and edges with two equivalent Cr(3)Se4N2 octahedra. The corner-sharing octahedral tilt angles range from 56-66°. N(1) is bonded to one Cr(1), one Cr(2), and two equivalent Cr(3) atoms to form distorted NCr4 trigonal pyramids that share corners with four equivalent Se(1)Cr4 tetrahedra, corners with six equivalent Se(2)Cr5 trigonal bipyramids, edges with two equivalent Se(2)Cr5 trigonal bipyramids, and edges with two equivalent N(1)Cr4 trigonal pyramids. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded to two equivalent Cr(2) and two equivalent Cr(3) atoms to form distorted SeCr4 tetrahedra that share corners with two equivalent Se(1)Cr4 tetrahedra, corners with six equivalent Se(2)Cr5 trigonal bipyramids, and corners with eight equivalent N(1)Cr4 trigonal pyramids. In the second Se site, Se(2) is bonded to two equivalent Cr(1) and three equivalent Cr(3) atoms to form distorted SeCr5 trigonal bipyramids that share corners with three equivalent Se(1)Cr4 tetrahedra, corners with four equivalent Se(2)Cr5 trigonal bipyramids, corners with six equivalent N(1)Cr4 trigonal pyramids, edges with four equivalent Se(2)Cr5 trigonal bipyramids, and edges with two equivalent N(1)Cr4 trigonal pyramids. is represented by the CIF file [CIF]
data_Cr4Se3N2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.077
_cell_length_b   10.399
_cell_length_c   9.210
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   582.002
_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
  Cr  Cr0  1  0.579  0.250  0.867  1.0
  Cr  Cr1  1  0.079  0.250  0.633  1.0
  Cr  Cr2  1  0.421  0.750  0.133  1.0
  Cr  Cr3  1  0.921  0.750  0.367  1.0
  Cr  Cr4  1  0.795  0.250  0.400  1.0
  Cr  Cr5  1  0.295  0.250  0.100  1.0
  Cr  Cr6  1  0.205  0.750  0.600  1.0
  Cr  Cr7  1  0.705  0.750  0.900  1.0
  Cr  Cr8  1  0.709  0.473  0.073  1.0
  Cr  Cr9  1  0.209  0.027  0.427  1.0
  Cr  Cr10  1  0.291  0.973  0.927  1.0
  Cr  Cr11  1  0.791  0.527  0.573  1.0
  Cr  Cr12  1  0.291  0.527  0.927  1.0
  Cr  Cr13  1  0.791  0.973  0.573  1.0
  Cr  Cr14  1  0.709  0.027  0.073  1.0
  Cr  Cr15  1  0.209  0.473  0.427  1.0
  Se  Se16  1  0.889  0.250  0.144  1.0
  Se  Se17  1  0.389  0.250  0.356  1.0
  Se  Se18  1  0.111  0.750  0.856  1.0
  Se  Se19  1  0.611  0.750  0.644  1.0
  Se  Se20  1  0.585  0.570  0.324  1.0
  Se  Se21  1  0.085  0.930  0.176  1.0
  Se  Se22  1  0.415  0.070  0.676  1.0
  Se  Se23  1  0.915  0.430  0.824  1.0
  Se  Se24  1  0.415  0.430  0.676  1.0
  Se  Se25  1  0.915  0.070  0.824  1.0
  Se  Se26  1  0.585  0.930  0.324  1.0
  Se  Se27  1  0.085  0.570  0.176  1.0
  N  N28  1  0.554  0.623  0.995  1.0
  N  N29  1  0.054  0.877  0.505  1.0
  N  N30  1  0.446  0.123  0.005  1.0
  N  N31  1  0.946  0.377  0.495  1.0
  N  N32  1  0.446  0.377  0.005  1.0
  N  N33  1  0.946  0.123  0.495  1.0
  N  N34  1  0.554  0.877  0.995  1.0
  N  N35  1  0.054  0.623  0.505  1.0
[/CIF]
.