data_Rb3AlAg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.85
_cell_length_b   6.85
_cell_length_c   6.85
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Rb3AlAg
_chemical_formula_sum   'Rb3 Al1 Ag1'
_cell_volume   321.68
_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
  Rb  Rb0  1  0.0  0.43  0.0  1.0
  Rb  Rb1  1  0.0  0.0  0.43  1.0
  Rb  Rb2  1  0.43  0.0  0.0  1.0
  Al  Al4  1  0.0  0.0  0.0  1.0
  Ag  Ag3  1  0.43  0.43  0.43  1.0

data_Rb3AlAg
_symmetry_space_group_name_H-M   R3m
_cell_length_a   9.69
_cell_length_b   9.69
_cell_length_c   11.87
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   Rb3AlAg
_chemical_formula_sum   'Rb9 Al3 Ag3'
_cell_volume   965.05
_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
  Rb  Rb0  9  0.19  0.38  0.81  1.0
  Al  Al1  3  0.0  0.0  0.0  1.0
  Ag  Ag2  3  0.0  0.0  0.43  1.0

Rb Rb Rb Al Ag
Rb3AgAl crystallizes in the trigonal R3m space group. Rb(1) is bonded in a distorted T-shaped geometry to one Ag(1) and two equivalent Al(1) atoms. The Rb(1)-Ag(1) bond length is 4.13 Å. There is one shorter (2.92 Å) and one longer (3.93 Å) Rb(1)-Al(1) bond length. Ag(1) is bonded in a 3-coordinate geometry to three equivalent Rb(1) atoms. Al(1) is bonded to six equivalent Rb(1) atoms to form corner-sharing AlRb6 octahedra. The corner-sharing octahedra are not tilted.