data_BaCaSe2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.73
_cell_length_b   4.81
_cell_length_c   7.05
_cell_angle_alpha   90.0
_cell_angle_beta   98.9
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   BaCaSe2
_chemical_formula_sum   'Ba1 Ca1 Se2'
_cell_volume   125.13
_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
  Ba  Ba0  1  0.32  0.0  0.48  1.0
  Ca  Ca1  1  0.0  0.0  0.0  1.0
  Se  Se2  1  0.53  0.41  0.74  1.0
  Se  Se3  1  0.11  0.41  0.23  1.0

data_BaCaSe2
_symmetry_space_group_name_H-M   P1
_cell_length_a   3.73
_cell_length_b   4.81
_cell_length_c   7.05
_cell_angle_alpha   90.0
_cell_angle_beta   98.9
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   BaCaSe2
_chemical_formula_sum   'Ba1 Ca1 Se2'
_cell_volume   125.13
_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
  Ba  Ba0  1  0.32  0.0  0.48  1.0
  Ca  Ca1  1  0.0  0.0  0.0  1.0
  Se  Se2  1  0.11  0.41  0.23  1.0
  Se  Se3  1  0.53  0.41  0.74  1.0

Ba Ca Se Se
BaCaSe2 crystallizes in the triclinic P1 space group. Ba(1) is bonded in a 4-coordinate geometry to two equivalent Se(1) and two equivalent Se(2) atoms. There is one shorter (2.70 Å) and one longer (3.41 Å) Ba(1)-Se(1) bond length. There is one shorter (2.70 Å) and one longer (3.41 Å) Ba(1)-Se(2) bond length. Ca(1) is bonded in a 1-coordinate geometry to two equivalent Se(2) and three equivalent Se(1) atoms. There is one shorter (2.52 Å) and one longer (3.27 Å) Ca(1)-Se(2) bond length. There are a spread of Ca(1)-Se(1) bond distances ranging from 3.04-3.68 Å. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a 5-coordinate geometry to two equivalent Ba(1) and three equivalent Ca(1) atoms. In the second Se site, Se(2) is bonded in a 4-coordinate geometry to two equivalent Ba(1) and two equivalent Ca(1) atoms.