data_CaAg2Br
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.19
_cell_length_b   5.19
_cell_length_c   5.19
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   CaAg2Br
_chemical_formula_sum   'Ca1 Ag2 Br1'
_cell_volume   98.88
_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
  Ca  Ca3  1  0.0  0.0  0.0  1.0
  Ag  Ag0  1  0.51  0.51  0.51  1.0
  Ag  Ag1  1  0.84  0.84  0.84  1.0
  Br  Br2  1  0.67  0.67  0.67  1.0

data_CaAg2Br
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.19
_cell_length_b   5.19
_cell_length_c   12.71
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   CaAg2Br
_chemical_formula_sum   'Ca3 Ag6 Br3'
_cell_volume   296.64
_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
  Ca  Ca0  3  0.0  0.0  0.0  1.0
  Ag  Ag1  3  0.0  0.0  0.16  1.0
  Ag  Ag2  3  0.0  0.0  0.49  1.0
  Br  Br3  3  0.0  0.0  0.33  1.0

Ca Ag Ag Br
Ca Ag Ag Br 0 2 - - - 1 3 o o o 2 3 o o o 
CaAg2Br crystallizes in the trigonal R3m space group. Ca(1) is bonded to one Ag(2) and three equivalent Br(1) atoms to form distorted CaAgBr3 trigonal pyramids that share  a cornercorner with one Br(1)Ca3Ag2 trigonal bipyramid and corners with six equivalent Ca(1)AgBr3 trigonal pyramids. The Ca(1)-Ag(2) bond length is 2.10 Å. All Ca(1)-Br(1) bond lengths are 3.00 Å. There are two inequivalent Ag sites. In the first Ag site, Ag(1) is bonded in a single-bond geometry to one Br(1) atom. The Ag(1)-Br(1) bond length is 2.10 Å. In the second Ag site, Ag(2) is bonded in a linear geometry to one Ca(1) and one Br(1) atom. The Ag(2)-Br(1) bond length is 2.10 Å. Br(1) is bonded to three equivalent Ca(1), one Ag(1), and one Ag(2) atom to form BrCa3Ag2 trigonal bipyramids that share corners with six equivalent Br(1)Ca3Ag2 trigonal bipyramids and  a cornercorner with one Ca(1)AgBr3 trigonal pyramid.