data_Mg2SiRh
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.48
_cell_length_b   4.48
_cell_length_c   4.48
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Mg2SiRh
_chemical_formula_sum   'Mg2 Si1 Rh1'
_cell_volume   63.53
_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
  Mg  Mg0  1  0.75  0.75  0.75  1.0
  Mg  Mg1  1  0.58  0.58  0.58  1.0
  Si  Si3  1  0.0  0.0  0.0  1.0
  Rh  Rh2  1  0.17  0.17  0.17  1.0

data_Mg2SiRh
_symmetry_space_group_name_H-M   R3m
_cell_length_a   4.48
_cell_length_b   4.48
_cell_length_c   10.97
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   Mg2SiRh
_chemical_formula_sum   'Mg6 Si3 Rh3'
_cell_volume   190.59
_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
  Mg  Mg0  3  0.0  0.0  0.25  1.0
  Mg  Mg1  3  0.0  0.0  0.42  1.0
  Si  Si2  3  0.0  0.0  0.0  1.0
  Rh  Rh3  3  0.0  0.0  0.83  1.0

Mg Mg Si Rh
Mg Mg Si Rh 0 1 o o o 2 3 o o o 
Mg2RhSi crystallizes in the trigonal R3m space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 8-coordinate geometry to one Mg(2), three equivalent Rh(1), and four equivalent Si(1) atoms. The Mg(1)-Mg(2) bond length is 1.83 Å. All Mg(1)-Rh(1) bond lengths are 2.74 Å. All Mg(1)-Si(1) bond lengths are 2.74 Å. In the second Mg site, Mg(2) is bonded in a 7-coordinate geometry to one Mg(1), three equivalent Rh(1), and three equivalent Si(1) atoms. All Mg(2)-Rh(1) bond lengths are 2.74 Å. All Mg(2)-Si(1) bond lengths are 2.74 Å. Rh(1) is bonded in a 1-coordinate geometry to three equivalent Mg(1), three equivalent Mg(2), and one Si(1) atom. The Rh(1)-Si(1) bond length is 1.83 Å. Si(1) is bonded in a distorted single-bond geometry to three equivalent Mg(2), four equivalent Mg(1), and one Rh(1) atom.