data_SrZn2Se
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.2
_cell_length_b   5.2
_cell_length_c   5.2
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   SrZn2Se
_chemical_formula_sum   'Sr1 Zn2 Se1'
_cell_volume   99.48
_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
  Sr  Sr1  1  0.68  0.68  0.68  1.0
  Zn  Zn2  1  0.84  0.84  0.84  1.0
  Zn  Zn3  1  0.52  0.52  0.52  1.0
  Se  Se0  1  0.0  0.0  0.0  1.0

data_SrZn2Se
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.2
_cell_length_b   5.2
_cell_length_c   12.74
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   SrZn2Se
_chemical_formula_sum   'Sr3 Zn6 Se3'
_cell_volume   298.43
_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
  Sr  Sr0  3  0.0  0.0  0.32  1.0
  Zn  Zn1  3  0.0  0.0  0.16  1.0
  Zn  Zn2  3  0.0  0.0  0.48  1.0
  Se  Se3  3  0.0  0.0  0.0  1.0

Sr Zn Zn Se
Sr Zn Zn Se 0 2 o o o 0 1 o o o 1 3 + + + 
SrZn2Se crystallizes in the trigonal R3m space group. Sr(1) is bonded to one Zn(1), one Zn(2), and three equivalent Se(1) atoms to form distorted SrZn2Se3 trigonal bipyramids that share corners with six equivalent Sr(1)Zn2Se3 trigonal bipyramids and  a cornercorner with one Se(1)Sr3Zn trigonal pyramid. The Sr(1)-Zn(1) bond length is 2.05 Å. The Sr(1)-Zn(2) bond length is 2.05 Å. All Sr(1)-Se(1) bond lengths are 3.01 Å. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded in a linear geometry to one Sr(1) and one Se(1) atom. The Zn(1)-Se(1) bond length is 2.05 Å. In the second Zn site, Zn(2) is bonded in a single-bond geometry to one Sr(1) atom. Se(1) is bonded to three equivalent Sr(1) and one Zn(1) atom to form SeSr3Zn trigonal pyramids that share  a cornercorner with one Sr(1)Zn2Se3 trigonal bipyramid and corners with six equivalent Se(1)Sr3Zn trigonal pyramids.