data_CrN3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.51
_cell_length_b   3.51
_cell_length_c   3.51
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   CrN3
_chemical_formula_sum   'Cr1 N3'
_cell_volume   30.6
_cell_formula_units_Z   1
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  0.48  0.48  0.48  1.0
  N  N1  1  0.72  0.72  0.72  1.0
  N  N2  1  0.0  0.0  0.0  1.0
  N  N3  1  0.24  0.24  0.24  1.0

data_CrN3
_symmetry_space_group_name_H-M   R3m
_cell_length_a   3.51
_cell_length_b   3.51
_cell_length_c   8.6
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   CrN3
_chemical_formula_sum   'Cr3 N9'
_cell_volume   91.81
_cell_formula_units_Z   3
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  '-y, x-y, z'
  3  '-x+y, -x, z'
  4  '-y, -x, z'
  5  '-x+y, y, z'
  6  'x, x-y, z'
  7  'x+1/3, y+2/3, z+2/3'
  8  '-y+1/3, x-y+2/3, z+2/3'
  9  '-x+y+1/3, -x+2/3, z+2/3'
  10  '-y+1/3, -x+2/3, z+2/3'
  11  '-x+y+1/3, y+2/3, z+2/3'
  12  'x+1/3, x-y+2/3, z+2/3'
  13  'x+2/3, y+1/3, z+1/3'
  14  '-y+2/3, x-y+1/3, z+1/3'
  15  '-x+y+2/3, -x+1/3, z+1/3'
  16  '-y+2/3, -x+1/3, z+1/3'
  17  '-x+y+2/3, y+1/3, z+1/3'
  18  'x+2/3, x-y+1/3, z+1/3'
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  3  0.0  0.0  0.52  1.0
  N  N1  3  0.0  0.0  0.0  1.0
  N  N2  3  0.0  0.0  0.28  1.0
  N  N3  3  0.0  0.0  0.76  1.0

Cr N N N
Cr N N N 0 3 o o o 0 3 o o + 0 3 + o o 0 3 o + o 0 1 o - o 0 1 - o o 0 1 o o - 0 1 o o o 0 2 o o + 0 2 o + o 0 2 o + + 0 2 + o o 0 2 + o + 0 2 + + o 1 3 o o + 1 3 o + o 1 3 o + + 1 3 + o o 1 3 + o + 1 3 + + o 1 2 o + + 1 2 + o + 1 2 + + o 1 2 + + + 2 3 o - o 2 3 - o o 2 3 o o - 2 3 o o o 
CrN3 is alpha bismuth trifluoride structured and crystallizes in the trigonal R3m space group. Cr(1) is bonded in a distorted body-centered cubic geometry to four equivalent N(1), four equivalent N(3), and six equivalent N(2) atoms. There is one shorter (2.08 Å) and three longer (2.18 Å) Cr(1)-N(1) bond lengths. There is one shorter (2.08 Å) and three longer (2.18 Å) Cr(1)-N(3) bond lengths. There are three shorter (2.40 Å) and three longer (2.57 Å) Cr(1)-N(2) bond lengths. There are three inequivalent N sites. In the first N site, N(1) is bonded to four equivalent Cr(1) and three equivalent N(2) atoms to form distorted NCr4N3 tetrahedra that share corners with six equivalent N(1)Cr4N3 tetrahedra, corners with seven equivalent N(3)Cr4N4 tetrahedra, edges with six equivalent N(1)Cr4N3 tetrahedra, and faces with six equivalent N(3)Cr4N4 tetrahedra. All N(1)-N(2) bond lengths are 2.09 Å. In the second N site, N(2) is bonded in a 13-coordinate geometry to six equivalent Cr(1), three equivalent N(1), and four equivalent N(3) atoms. There is one shorter (2.08 Å) and three longer (2.18 Å) N(2)-N(3) bond lengths. In the third N site, N(3) is bonded to four equivalent Cr(1) and four equivalent N(2) atoms to form distorted NCr4N4 tetrahedra that share corners with seven equivalent N(1)Cr4N3 tetrahedra, edges with twelve equivalent N(3)Cr4N4 tetrahedra, and faces with six equivalent N(1)Cr4N3 tetrahedra.