The material structure described by Ca4N4Se crystallizes in the orthorhombic Pnma space group. There are four inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 6-coordinate geometry to one N(4), two equivalent N(2), and three equivalent N(3) atoms. In the second Ca site, Ca(2) is bonded to one N(1), two equivalent N(2), two equivalent N(3), and two equivalent Se(1) atoms to form distorted CaSe2N5 pentagonal bipyramids that share corners with two equivalent Ca(3)Se3N4 pentagonal bipyramids, edges with three equivalent Ca(3)Se3N4 pentagonal bipyramids, and faces with two equivalent Ca(2)Se2N5 pentagonal bipyramids. In the third Ca site, Ca(3) is bonded to two equivalent N(1), two equivalent N(4), and three equivalent Se(1) atoms to form distorted CaSe3N4 pentagonal bipyramids that share corners with two equivalent N(1)Ca5N octahedra, corners with two equivalent Ca(2)Se2N5 pentagonal bipyramids, edges with two equivalent Ca(3)Se3N4 pentagonal bipyramids, edges with three equivalent Ca(2)Se2N5 pentagonal bipyramids, and faces with two equivalent Ca(3)Se3N4 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 109°. In the fourth Ca site, Ca(4) is bonded in a 7-coordinate geometry to one N(2), two equivalent N(1), two equivalent N(4), and two equivalent Se(1) atoms. There are four inequivalent N sites. In the first N site, N(4) is bonded in a 6-coordinate geometry to one Ca(1), two equivalent Ca(3), two equivalent Ca(4), and one N(1) atom. In the second N site, N(1) is bonded to one Ca(2), two equivalent Ca(3), two equivalent Ca(4), and one N(4) atom to form distorted NCa5N octahedra that share corners with two equivalent Ca(3)Se3N4 pentagonal bipyramids, corners with four equivalent Se(1)Ca7 pentagonal bipyramids, edges with two equivalent N(1)Ca5N octahedra, and edges with four equivalent Se(1)Ca7 pentagonal bipyramids. In the third N site, N(2) is bonded in a 6-coordinate geometry to one Ca(4), two equivalent Ca(1), two equivalent Ca(2), and one N(3) atom. In the fourth N site, N(3) is bonded in a 6-coordinate geometry to two equivalent Ca(2), three equivalent Ca(1), and one N(2) atom. Se(1) is bonded to two equivalent Ca(2), two equivalent Ca(4), and three equivalent Ca(3) atoms to form distorted SeCa7 pentagonal bipyramids that share corners with four equivalent N(1)Ca5N octahedra, edges with four equivalent N(1)Ca5N octahedra, edges with two equivalent Se(1)Ca7 pentagonal bipyramids, and faces with two equivalent Se(1)Ca7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 9-13°. is represented by the CIF file [CIF]
data_Ca4SeN4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.875
_cell_length_b   3.638
_cell_length_c   13.401
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   627.648
_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
  Ca  Ca0  1  0.007  0.250  0.116  1.0
  Ca  Ca1  1  0.507  0.250  0.384  1.0
  Ca  Ca2  1  0.993  0.750  0.884  1.0
  Ca  Ca3  1  0.493  0.750  0.616  1.0
  Ca  Ca4  1  0.768  0.250  0.032  1.0
  Ca  Ca5  1  0.268  0.250  0.468  1.0
  Ca  Ca6  1  0.232  0.750  0.968  1.0
  Ca  Ca7  1  0.732  0.750  0.532  1.0
  Ca  Ca8  1  0.459  0.250  0.868  1.0
  Ca  Ca9  1  0.959  0.250  0.632  1.0
  Ca  Ca10  1  0.541  0.750  0.132  1.0
  Ca  Ca11  1  0.041  0.750  0.368  1.0
  Ca  Ca12  1  0.242  0.250  0.741  1.0
  Ca  Ca13  1  0.742  0.250  0.759  1.0
  Ca  Ca14  1  0.758  0.750  0.259  1.0
  Ca  Ca15  1  0.258  0.750  0.241  1.0
  Se  Se16  1  0.366  0.250  0.088  1.0
  Se  Se17  1  0.866  0.250  0.412  1.0
  Se  Se18  1  0.634  0.750  0.912  1.0
  Se  Se19  1  0.134  0.750  0.588  1.0
  N  N20  1  0.668  0.250  0.165  1.0
  N  N21  1  0.168  0.250  0.335  1.0
  N  N22  1  0.332  0.750  0.835  1.0
  N  N23  1  0.832  0.750  0.665  1.0
  N  N24  1  0.132  0.250  0.877  1.0
  N  N25  1  0.632  0.250  0.623  1.0
  N  N26  1  0.868  0.750  0.123  1.0
  N  N27  1  0.368  0.750  0.377  1.0
  N  N28  1  0.093  0.250  0.968  1.0
  N  N29  1  0.593  0.250  0.532  1.0
  N  N30  1  0.907  0.750  0.032  1.0
  N  N31  1  0.407  0.750  0.468  1.0
  N  N32  1  0.610  0.250  0.249  1.0
  N  N33  1  0.110  0.250  0.251  1.0
  N  N34  1  0.390  0.750  0.751  1.0
  N  N35  1  0.890  0.750  0.749  1.0
[/CIF]
.
The material structure described by Ca4N4Se crystallizes in the orthorhombic Pnma space group. There are four inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 6-coordinate geometry to one N(4), two equivalent N(2), and three equivalent N(3) atoms. In the second Ca site, Ca(2) is bonded to one N(1), two equivalent N(2), two equivalent N(3), and two equivalent Se(1) atoms to form distorted CaSe2N5 pentagonal bipyramids that share corners with two equivalent Ca(3)Se3N4 pentagonal bipyramids, edges with three equivalent Ca(3)Se3N4 pentagonal bipyramids, and faces with two equivalent Ca(2)Se2N5 pentagonal bipyramids. In the third Ca site, Ca(3) is bonded to two equivalent N(1), two equivalent N(4), and three equivalent Se(1) atoms to form distorted CaSe3N4 pentagonal bipyramids that share corners with two equivalent N(1)Ca5N octahedra, corners with two equivalent Ca(2)Se2N5 pentagonal bipyramids, edges with two equivalent Ca(3)Se3N4 pentagonal bipyramids, edges with three equivalent Ca(2)Se2N5 pentagonal bipyramids, and faces with two equivalent Ca(3)Se3N4 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 109°. In the fourth Ca site, Ca(4) is bonded in a 7-coordinate geometry to one N(2), two equivalent N(1), two equivalent N(4), and two equivalent Se(1) atoms. There are four inequivalent N sites. In the first N site, N(4) is bonded in a 6-coordinate geometry to one Ca(1), two equivalent Ca(3), two equivalent Ca(4), and one N(1) atom. In the second N site, N(1) is bonded to one Ca(2), two equivalent Ca(3), two equivalent Ca(4), and one N(4) atom to form distorted NCa5N octahedra that share corners with two equivalent Ca(3)Se3N4 pentagonal bipyramids, corners with four equivalent Se(1)Ca7 pentagonal bipyramids, edges with two equivalent N(1)Ca5N octahedra, and edges with four equivalent Se(1)Ca7 pentagonal bipyramids. In the third N site, N(2) is bonded in a 6-coordinate geometry to one Ca(4), two equivalent Ca(1), two equivalent Ca(2), and one N(3) atom. In the fourth N site, N(3) is bonded in a 6-coordinate geometry to two equivalent Ca(2), three equivalent Ca(1), and one N(2) atom. Se(1) is bonded to two equivalent Ca(2), two equivalent Ca(4), and three equivalent Ca(3) atoms to form distorted SeCa7 pentagonal bipyramids that share corners with four equivalent N(1)Ca5N octahedra, edges with four equivalent N(1)Ca5N octahedra, edges with two equivalent Se(1)Ca7 pentagonal bipyramids, and faces with two equivalent Se(1)Ca7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 9-13°. is represented by the CIF file [CIF]
data_Ca4SeN4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.875
_cell_length_b   3.638
_cell_length_c   13.401
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   627.648
_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
  Ca  Ca0  1  0.007  0.250  0.116  1.0
  Ca  Ca1  1  0.507  0.250  0.384  1.0
  Ca  Ca2  1  0.993  0.750  0.884  1.0
  Ca  Ca3  1  0.493  0.750  0.616  1.0
  Ca  Ca4  1  0.768  0.250  0.032  1.0
  Ca  Ca5  1  0.268  0.250  0.468  1.0
  Ca  Ca6  1  0.232  0.750  0.968  1.0
  Ca  Ca7  1  0.732  0.750  0.532  1.0
  Ca  Ca8  1  0.459  0.250  0.868  1.0
  Ca  Ca9  1  0.959  0.250  0.632  1.0
  Ca  Ca10  1  0.541  0.750  0.132  1.0
  Ca  Ca11  1  0.041  0.750  0.368  1.0
  Ca  Ca12  1  0.242  0.250  0.741  1.0
  Ca  Ca13  1  0.742  0.250  0.759  1.0
  Ca  Ca14  1  0.758  0.750  0.259  1.0
  Ca  Ca15  1  0.258  0.750  0.241  1.0
  Se  Se16  1  0.366  0.250  0.088  1.0
  Se  Se17  1  0.866  0.250  0.412  1.0
  Se  Se18  1  0.634  0.750  0.912  1.0
  Se  Se19  1  0.134  0.750  0.588  1.0
  N  N20  1  0.668  0.250  0.165  1.0
  N  N21  1  0.168  0.250  0.335  1.0
  N  N22  1  0.332  0.750  0.835  1.0
  N  N23  1  0.832  0.750  0.665  1.0
  N  N24  1  0.132  0.250  0.877  1.0
  N  N25  1  0.632  0.250  0.623  1.0
  N  N26  1  0.868  0.750  0.123  1.0
  N  N27  1  0.368  0.750  0.377  1.0
  N  N28  1  0.093  0.250  0.968  1.0
  N  N29  1  0.593  0.250  0.532  1.0
  N  N30  1  0.907  0.750  0.032  1.0
  N  N31  1  0.407  0.750  0.468  1.0
  N  N32  1  0.610  0.250  0.249  1.0
  N  N33  1  0.110  0.250  0.251  1.0
  N  N34  1  0.390  0.750  0.751  1.0
  N  N35  1  0.890  0.750  0.749  1.0
[/CIF]
.