data_SrCoSe2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.0
_cell_length_b   5.0
_cell_length_c   5.0
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   SrCoSe2
_chemical_formula_sum   'Sr1 Co1 Se2'
_cell_volume   88.3
_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  Sr3  1  0.53  0.53  0.53  1.0
  Co  Co0  1  0.0  0.0  0.0  1.0
  Se  Se1  1  0.77  0.77  0.77  1.0
  Se  Se2  1  0.3  0.3  0.3  1.0

data_SrCoSe2
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.0
_cell_length_b   5.0
_cell_length_c   12.24
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   SrCoSe2
_chemical_formula_sum   'Sr3 Co3 Se6'
_cell_volume   264.89
_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  0.47  1.0
  Co  Co1  3  0.0  0.0  -0.0  1.0
  Se  Se2  3  0.0  0.0  0.23  1.0
  Se  Se3  3  0.0  0.0  0.7  1.0

Sr Co Se Se
Sr Co Se Se 0 3 o o o 0 3 o o + 0 3 + o o 0 3 o + o 0 2 o - o 0 2 - o o 0 2 o o - 0 2 o o o 0 1 o + + 0 1 + o + 0 1 + + o 1 2 - - - 1 2 - - o 1 2 o - - 1 2 - o - 1 3 - o o 1 3 o - o 1 3 o o - 2 3 o o + 2 3 o + o 2 3 + o o 
SrCoSe2 is Heusler structured and crystallizes in the trigonal R3m space group. Sr(1) is bonded in a 8-coordinate geometry to three equivalent Co(1), four equivalent Se(1), and four equivalent Se(2) atoms. All Sr(1)-Co(1) bond lengths are 3.31 Å. There is one shorter (2.85 Å) and three longer (3.14 Å) Sr(1)-Se(1) bond lengths. There is one shorter (2.85 Å) and three longer (3.14 Å) Sr(1)-Se(2) bond lengths. Co(1) is bonded in a 10-coordinate geometry to three equivalent Sr(1), three equivalent Se(2), and four equivalent Se(1) atoms. All Co(1)-Se(2) bond lengths are 2.91 Å. There is one shorter (2.85 Å) and three longer (3.14 Å) Co(1)-Se(1) bond lengths. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a distorted body-centered cubic geometry to four equivalent Sr(1) and four equivalent Co(1) atoms. In the second Se site, Se(2) is bonded to four equivalent Sr(1) and three equivalent Co(1) atoms to form a mixture of distorted corner and edge-sharing SeSr4Co3 hexagonal pyramids.