data_RbCuSi2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.89
_cell_length_b   4.89
_cell_length_c   4.89
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   RbCuSi2
_chemical_formula_sum   'Rb1 Cu1 Si2'
_cell_volume   82.74
_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  Rb1  1  0.46  0.46  0.46  1.0
  Cu  Cu0  1  0.0  0.0  0.0  1.0
  Si  Si2  1  0.19  0.19  0.19  1.0
  Si  Si3  1  0.73  0.73  0.73  1.0

data_RbCuSi2
_symmetry_space_group_name_H-M   R3m
_cell_length_a   4.89
_cell_length_b   4.89
_cell_length_c   11.98
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   RbCuSi2
_chemical_formula_sum   'Rb3 Cu3 Si6'
_cell_volume   248.21
_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  0.54  1.0
  Cu  Cu1  3  0.0  0.0  0.0  1.0
  Si  Si2  3  0.0  0.0  0.27  1.0
  Si  Si3  3  0.0  0.0  0.81  1.0

Rb Cu Si Si
Rb Cu Si Si 0 2 o o o 0 2 o o + 0 2 o + o 0 2 + o o 0 1 o o + 0 1 o + o 0 1 + o o 0 3 - o o 0 3 o - o 0 3 o o - 0 3 o o o 1 2 o o o 1 3 o - - 1 3 - o - 1 3 - - o 1 3 - - - 2 3 o - - 2 3 - o - 2 3 - - o 
RbCuSi2 is Heusler structured and crystallizes in the trigonal R3m space group. Rb(1) is bonded in a 11-coordinate geometry to three equivalent Cu(1), four equivalent Si(1), and four equivalent Si(2) atoms. All Rb(1)-Cu(1) bond lengths are 3.20 Å. There are three shorter (2.92 Å) and one longer (3.24 Å) Rb(1)-Si(1) bond length. There are three shorter (2.92 Å) and one longer (3.24 Å) Rb(1)-Si(2) bond length. Cu(1) is bonded in a 7-coordinate geometry to three equivalent Rb(1), one Si(1), and three equivalent Si(2) atoms. The Cu(1)-Si(1) bond length is 2.25 Å. All Cu(1)-Si(2) bond lengths are 2.92 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to four equivalent Rb(1) and one Cu(1) atom to form distorted corner-sharing SiRb4Cu trigonal bipyramids. In the second Si site, Si(2) is bonded in a 4-coordinate geometry to four equivalent Rb(1) and three equivalent Cu(1) atoms.