data_YAsBr2
_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   YAsBr2
_chemical_formula_sum   'Y1 As1 Br2'
_cell_volume   99.23
_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  Y3  1  0.84  0.84  0.84  1.0
  As  As0  1  0.0  0.0  0.0  1.0
  Br  Br1  1  0.67  0.67  0.67  1.0
  Br  Br2  1  0.51  0.51  0.51  1.0

data_YAsBr2
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.2
_cell_length_b   5.2
_cell_length_c   12.73
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   YAsBr2
_chemical_formula_sum   'Y3 As3 Br6'
_cell_volume   297.7
_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
  Y  Y0  3  0.0  0.0  0.16  1.0
  As  As1  3  0.0  0.0  0.0  1.0
  Br  Br2  3  0.0  0.0  0.33  1.0
  Br  Br3  3  0.0  0.0  0.49  1.0

Y As Br Br
YAsBr2 crystallizes in the trigonal R3m space group. Y(1) is bonded to one As(1), one Br(1), and three equivalent Br(2) atoms to form distorted YAsBr4 trigonal bipyramids that share corners with six equivalent Y(1)AsBr4 trigonal bipyramids and  a cornercorner with one Br(2)Y3Br trigonal pyramid. The Y(1)-As(1) bond length is 2.07 Å. The Y(1)-Br(1) bond length is 2.07 Å. All Y(1)-Br(2) bond lengths are 3.00 Å. As(1) is bonded in a distorted single-bond geometry to one Y(1) atom. There are two inequivalent Br sites. In the first Br site, Br(1) is bonded in a single-bond geometry to one Y(1) and one Br(2) atom. The Br(1)-Br(2) bond length is 2.07 Å. In the second Br site, Br(2) is bonded to three equivalent Y(1) and one Br(1) atom to form BrY3Br trigonal pyramids that share  a cornercorner with one Y(1)AsBr4 trigonal bipyramid and corners with six equivalent Br(2)Y3Br trigonal pyramids.