The structure described by Ca4N4Se crystallizes in the triclinic P-1 space group. There are four inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 5-coordinate geometry to one N(4), two equivalent N(2), and two equivalent N(3) atoms. In the second Ca site, Ca(2) is bonded in a 4-coordinate geometry to two equivalent N(2) and two equivalent N(3) atoms. In the third Ca site, Ca(3) is bonded to one N(3), two equivalent N(1), and two equivalent N(4) atoms to form a mixture of distorted corner and edge-sharing CaN5 trigonal bipyramids. In the fourth Ca site, Ca(4) is bonded to one N(2), two equivalent N(1), and two equivalent N(4) atoms to form a mixture of distorted corner and edge-sharing CaN5 trigonal bipyramids. There are four inequivalent N sites. In the first N site, N(1) is bonded to two equivalent Ca(3), two equivalent Ca(4), and one Se(1) atom to form NCa4Se trigonal bipyramids that share  a cornercorner with one N(2)Ca5Se octahedra,  a cornercorner with one N(3)Ca5Se octahedra, corners with four equivalent N(4)Ca5 square pyramids,  an edgeedge with one N(2)Ca5Se octahedra,  an edgeedge with one N(3)Ca5Se octahedra, edges with two equivalent N(4)Ca5 square pyramids, and edges with two equivalent N(1)Ca4Se trigonal bipyramids. The corner-sharing octahedral tilt angles range from 53-65°. In the second N site, N(2) is bonded to one Ca(4), two equivalent Ca(1), two equivalent Ca(2), and one Se(1) atom to form distorted NCa5Se octahedra that share corners with three equivalent N(3)Ca5Se octahedra, corners with four equivalent N(4)Ca5 square pyramids,  a cornercorner with one N(1)Ca4Se trigonal bipyramid, edges with two equivalent N(2)Ca5Se octahedra,  an edgeedge with one N(1)Ca4Se trigonal bipyramid, and faces with two equivalent N(3)Ca5Se octahedra. The corner-sharing octahedral tilt angles range from 29-58°. In the third N site, N(3) is bonded to one Ca(3), two equivalent Ca(1), two equivalent Ca(2), and one Se(1) atom to form distorted NCa5Se octahedra that share corners with three equivalent N(2)Ca5Se octahedra, corners with four equivalent N(4)Ca5 square pyramids,  a cornercorner with one N(1)Ca4Se trigonal bipyramid, edges with two equivalent N(3)Ca5Se octahedra,  an edgeedge with one N(1)Ca4Se trigonal bipyramid, and faces with two equivalent N(2)Ca5Se octahedra. The corner-sharing octahedral tilt angles range from 29-58°. In the fourth N site, N(4) is bonded to one Ca(1), two equivalent Ca(3), and two equivalent Ca(4) atoms to form NCa5 square pyramids that share corners with four equivalent N(2)Ca5Se octahedra, corners with four equivalent N(3)Ca5Se octahedra, corners with four equivalent N(1)Ca4Se trigonal bipyramids, edges with two equivalent N(4)Ca5 square pyramids, and edges with two equivalent N(1)Ca4Se trigonal bipyramids. The corner-sharing octahedral tilt angles range from 47-70°. Se(1) is bonded in a distorted trigonal non-coplanar geometry to one N(1), one N(2), and one N(3) atom. is represented by the CIF file [CIF]
data_Ca4SeN4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.354
_cell_length_b   6.320
_cell_length_c   8.916
_cell_angle_alpha   82.769
_cell_angle_beta   69.683
_cell_angle_gamma   71.079
_symmetry_Int_Tables_number   1
_cell_volume   317.594
_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
  Ca  Ca0  1  0.824  0.599  0.163  1.0
  Ca  Ca1  1  0.176  0.401  0.837  1.0
  Ca  Ca2  1  0.705  0.207  1.000  1.0
  Ca  Ca3  1  0.295  0.793  0.000  1.0
  Ca  Ca4  1  0.709  0.491  0.578  1.0
  Ca  Ca5  1  0.291  0.509  0.422  1.0
  Ca  Ca6  1  0.237  0.985  0.575  1.0
  Ca  Ca7  1  0.763  0.015  0.425  1.0
  Se  Se8  1  0.799  0.807  0.796  1.0
  Se  Se9  1  0.201  0.193  0.204  1.0
  N  N10  1  0.951  0.755  0.590  1.0
  N  N11  1  0.049  0.245  0.410  1.0
  N  N12  1  0.017  0.826  0.881  1.0
  N  N13  1  0.983  0.174  0.119  1.0
  N  N14  1  0.729  0.548  0.882  1.0
  N  N15  1  0.271  0.452  0.118  1.0
  N  N16  1  0.562  0.741  0.397  1.0
  N  N17  1  0.438  0.259  0.603  1.0
[/CIF]
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The structure described by Ca4N4Se crystallizes in the triclinic P-1 space group. There are four inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 5-coordinate geometry to one N(4), two equivalent N(2), and two equivalent N(3) atoms. In the second Ca site, Ca(2) is bonded in a 4-coordinate geometry to two equivalent N(2) and two equivalent N(3) atoms. In the third Ca site, Ca(3) is bonded to one N(3), two equivalent N(1), and two equivalent N(4) atoms to form a mixture of distorted corner and edge-sharing CaN5 trigonal bipyramids. In the fourth Ca site, Ca(4) is bonded to one N(2), two equivalent N(1), and two equivalent N(4) atoms to form a mixture of distorted corner and edge-sharing CaN5 trigonal bipyramids. There are four inequivalent N sites. In the first N site, N(1) is bonded to two equivalent Ca(3), two equivalent Ca(4), and one Se(1) atom to form NCa4Se trigonal bipyramids that share  a cornercorner with one N(2)Ca5Se octahedra,  a cornercorner with one N(3)Ca5Se octahedra, corners with four equivalent N(4)Ca5 square pyramids,  an edgeedge with one N(2)Ca5Se octahedra,  an edgeedge with one N(3)Ca5Se octahedra, edges with two equivalent N(4)Ca5 square pyramids, and edges with two equivalent N(1)Ca4Se trigonal bipyramids. The corner-sharing octahedral tilt angles range from 53-65°. In the second N site, N(2) is bonded to one Ca(4), two equivalent Ca(1), two equivalent Ca(2), and one Se(1) atom to form distorted NCa5Se octahedra that share corners with three equivalent N(3)Ca5Se octahedra, corners with four equivalent N(4)Ca5 square pyramids,  a cornercorner with one N(1)Ca4Se trigonal bipyramid, edges with two equivalent N(2)Ca5Se octahedra,  an edgeedge with one N(1)Ca4Se trigonal bipyramid, and faces with two equivalent N(3)Ca5Se octahedra. The corner-sharing octahedral tilt angles range from 29-58°. In the third N site, N(3) is bonded to one Ca(3), two equivalent Ca(1), two equivalent Ca(2), and one Se(1) atom to form distorted NCa5Se octahedra that share corners with three equivalent N(2)Ca5Se octahedra, corners with four equivalent N(4)Ca5 square pyramids,  a cornercorner with one N(1)Ca4Se trigonal bipyramid, edges with two equivalent N(3)Ca5Se octahedra,  an edgeedge with one N(1)Ca4Se trigonal bipyramid, and faces with two equivalent N(2)Ca5Se octahedra. The corner-sharing octahedral tilt angles range from 29-58°. In the fourth N site, N(4) is bonded to one Ca(1), two equivalent Ca(3), and two equivalent Ca(4) atoms to form NCa5 square pyramids that share corners with four equivalent N(2)Ca5Se octahedra, corners with four equivalent N(3)Ca5Se octahedra, corners with four equivalent N(1)Ca4Se trigonal bipyramids, edges with two equivalent N(4)Ca5 square pyramids, and edges with two equivalent N(1)Ca4Se trigonal bipyramids. The corner-sharing octahedral tilt angles range from 47-70°. Se(1) is bonded in a distorted trigonal non-coplanar geometry to one N(1), one N(2), and one N(3) atom. is represented by the CIF file [CIF]
data_Ca4SeN4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.354
_cell_length_b   6.320
_cell_length_c   8.916
_cell_angle_alpha   82.769
_cell_angle_beta   69.683
_cell_angle_gamma   71.079
_symmetry_Int_Tables_number   1
_cell_volume   317.594
_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
  Ca  Ca0  1  0.824  0.599  0.163  1.0
  Ca  Ca1  1  0.176  0.401  0.837  1.0
  Ca  Ca2  1  0.705  0.207  1.000  1.0
  Ca  Ca3  1  0.295  0.793  0.000  1.0
  Ca  Ca4  1  0.709  0.491  0.578  1.0
  Ca  Ca5  1  0.291  0.509  0.422  1.0
  Ca  Ca6  1  0.237  0.985  0.575  1.0
  Ca  Ca7  1  0.763  0.015  0.425  1.0
  Se  Se8  1  0.799  0.807  0.796  1.0
  Se  Se9  1  0.201  0.193  0.204  1.0
  N  N10  1  0.951  0.755  0.590  1.0
  N  N11  1  0.049  0.245  0.410  1.0
  N  N12  1  0.017  0.826  0.881  1.0
  N  N13  1  0.983  0.174  0.119  1.0
  N  N14  1  0.729  0.548  0.882  1.0
  N  N15  1  0.271  0.452  0.118  1.0
  N  N16  1  0.562  0.741  0.397  1.0
  N  N17  1  0.438  0.259  0.603  1.0
[/CIF]
.