data_Ca2MnSi
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.88
_cell_length_b   4.88
_cell_length_c   4.88
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ca2MnSi
_chemical_formula_sum   'Ca2 Mn1 Si1'
_cell_volume   82.09
_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  Ca0  1  0.72  0.72  0.72  1.0
  Ca  Ca1  1  0.45  0.45  0.45  1.0
  Mn  Mn2  1  0.17  0.17  0.17  1.0
  Si  Si3  1  0.0  0.0  0.0  1.0

data_Ca2MnSi
_symmetry_space_group_name_H-M   R3m
_cell_length_a   4.88
_cell_length_b   4.88
_cell_length_c   11.95
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   Ca2MnSi
_chemical_formula_sum   'Ca6 Mn3 Si3'
_cell_volume   246.28
_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  0.28  1.0
  Ca  Ca1  3  0.0  0.0  0.55  1.0
  Mn  Mn2  3  0.0  0.0  0.83  1.0
  Si  Si3  3  0.0  0.0  0.0  1.0

Ca Ca Mn Si
Ca2MnSi crystallizes in the trigonal R3m space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 4-coordinate geometry to four equivalent Ca(2) and four equivalent Si(1) atoms. There are three shorter (2.90 Å) and one longer (3.29 Å) Ca(1)-Ca(2) bond length. There are three shorter (2.90 Å) and one longer (3.29 Å) Ca(1)-Si(1) bond length. In the second Ca site, Ca(2) is bonded in a 11-coordinate geometry to four equivalent Ca(1), four equivalent Mn(1), and three equivalent Si(1) atoms. There are three shorter (2.90 Å) and one longer (3.29 Å) Ca(2)-Mn(1) bond length. All Ca(2)-Si(1) bond lengths are 3.14 Å. Mn(1) is bonded in a distorted single-bond geometry to four equivalent Ca(2) and one Si(1) atom. The Mn(1)-Si(1) bond length is 2.08 Å. Si(1) is bonded in a 1-coordinate geometry to three equivalent Ca(2), four equivalent Ca(1), and one Mn(1) atom.