data_YAsSe3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.01
_cell_length_b   5.01
_cell_length_c   5.01
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   YAsSe3
_chemical_formula_sum   'Y1 As1 Se3'
_cell_volume   125.63
_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
  Y  Y0  1  0.5  0.5  0.5  1.0
  As  As1  1  0.0  0.0  0.0  1.0
  Se  Se2  1  0.0  0.5  0.0  1.0
  Se  Se3  1  0.0  0.0  0.5  1.0
  Se  Se4  1  0.5  0.0  0.0  1.0

data_YAsSe3
_symmetry_space_group_name_H-M   Pm-3m
_cell_length_a   5.01
_cell_length_b   5.01
_cell_length_c   5.01
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   221
_chemical_formula_structural   YAsSe3
_chemical_formula_sum   'Y1 As1 Se3'
_cell_volume   125.63
_cell_formula_units_Z   1
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  '-x, -y, -z'
  3  '-y, x, z'
  4  'y, -x, -z'
  5  '-x, -y, z'
  6  'x, y, -z'
  7  'y, -x, z'
  8  '-y, x, -z'
  9  'x, -y, -z'
  10  '-x, y, z'
  11  '-y, -x, -z'
  12  'y, x, z'
  13  '-x, y, -z'
  14  'x, -y, z'
  15  'y, x, -z'
  16  '-y, -x, z'
  17  'z, x, y'
  18  '-z, -x, -y'
  19  'z, -y, x'
  20  '-z, y, -x'
  21  'z, -x, -y'
  22  '-z, x, y'
  23  'z, y, -x'
  24  '-z, -y, x'
  25  '-z, x, -y'
  26  'z, -x, y'
  27  '-z, -y, -x'
  28  'z, y, x'
  29  '-z, -x, y'
  30  'z, x, -y'
  31  '-z, y, x'
  32  'z, -y, -x'
  33  'y, z, x'
  34  '-y, -z, -x'
  35  'x, z, -y'
  36  '-x, -z, y'
  37  '-y, z, -x'
  38  'y, -z, x'
  39  '-x, z, y'
  40  'x, -z, -y'
  41  '-y, -z, x'
  42  'y, z, -x'
  43  '-x, -z, -y'
  44  'x, z, y'
  45  'y, -z, -x'
  46  '-y, z, x'
  47  'x, -z, y'
  48  '-x, z, -y'
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
  Y  Y0  1  0.5  0.5  0.5  1.0
  As  As1  1  0.0  0.0  0.0  1.0
  Se  Se2  3  0.0  0.0  0.5  1.0

Y As Se Se Se
Y As Se Se Se 0 3 o o o 0 3 o + o 0 3 + o o 0 3 + + o 0 2 o o o 0 2 o o + 0 2 + o o 0 2 + o + 0 4 o o o 0 4 o o + 0 4 o + o 0 4 o + + 1 4 - o o 1 4 o o o 1 2 o - o 1 2 o o o 1 3 o o - 1 3 o o o 
YAsSe3 is (Cubic) Perovskite structured and crystallizes in the trigonal R3m space group. Y(1) is bonded to twelve equivalent Se(1) atoms to form YSe12 cuboctahedra that share corners with twelve equivalent Y(1)Se12 cuboctahedra, faces with six equivalent Y(1)Se12 cuboctahedra, and faces with eight equivalent As(1)Se6 octahedra. There are a spread of Y(1)-Se(1) bond distances ranging from 3.51-3.57 Å. As(1) is bonded to six equivalent Se(1) atoms to form AsSe6 octahedra that share corners with six equivalent As(1)Se6 octahedra and faces with eight equivalent Y(1)Se12 cuboctahedra. The corner-sharing octahedra are not tilted. There are three shorter (2.48 Å) and three longer (2.53 Å) As(1)-Se(1) bond lengths. Se(1) is bonded to four equivalent Y(1) and two equivalent As(1) atoms to form a mixture of distorted edge, face, and corner-sharing SeY4As2 octahedra. The corner-sharing octahedral tilt angles range from 0-60°.