data_RbLu2Si
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.22
_cell_length_b   5.22
_cell_length_c   5.22
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   RbLu2Si
_chemical_formula_sum   'Rb1 Lu2 Si1'
_cell_volume   100.67
_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  Rb2  1  0.69  0.69  0.69  1.0
  Lu  Lu0  1  0.85  0.85  0.85  1.0
  Lu  Lu1  1  0.54  0.54  0.54  1.0
  Si  Si3  1  0.0  0.0  0.0  1.0

data_RbLu2Si
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.22
_cell_length_b   5.22
_cell_length_c   12.79
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   RbLu2Si
_chemical_formula_sum   'Rb3 Lu6 Si3'
_cell_volume   302.0
_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  3  0.0  0.0  0.31  1.0
  Lu  Lu1  3  0.0  0.0  0.15  1.0
  Lu  Lu2  3  0.0  0.0  0.46  1.0
  Si  Si3  3  0.0  0.0  0.0  1.0

Rb Lu Lu Si
Rb Lu Lu Si 0 2 o o o 0 1 o o o 1 3 + + + 
RbLu2Si crystallizes in the trigonal R3m space group. Rb(1) is bonded to one Lu(1), one Lu(2), and three equivalent Si(1) atoms to form distorted RbLu2Si3 trigonal bipyramids that share corners with six equivalent Rb(1)Lu2Si3 trigonal bipyramids and  a cornercorner with one Si(1)Rb3Lu trigonal pyramid. The Rb(1)-Lu(1) bond length is 1.97 Å. The Rb(1)-Lu(2) bond length is 1.97 Å. All Rb(1)-Si(1) bond lengths are 3.03 Å. There are two inequivalent Lu sites. In the first Lu site, Lu(1) is bonded in a linear geometry to one Rb(1) and one Si(1) atom. The Lu(1)-Si(1) bond length is 1.97 Å. In the second Lu site, Lu(2) is bonded in a single-bond geometry to one Rb(1) atom. Si(1) is bonded to three equivalent Rb(1) and one Lu(1) atom to form distorted SiRb3Lu trigonal pyramids that share  a cornercorner with one Rb(1)Lu2Si3 trigonal bipyramid and corners with six equivalent Si(1)Rb3Lu trigonal pyramids.