data_CaSi2Sb
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.05
_cell_length_b   5.05
_cell_length_c   5.05
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   CaSi2Sb
_chemical_formula_sum   'Ca1 Si2 Sb1'
_cell_volume   90.88
_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  0.0  0.0  0.0  1.0
  Si  Si2  1  0.78  0.78  0.78  1.0
  Si  Si3  1  0.35  0.35  0.35  1.0
  Sb  Sb1  1  0.57  0.57  0.57  1.0

data_CaSi2Sb
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.05
_cell_length_b   5.05
_cell_length_c   12.36
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   CaSi2Sb
_chemical_formula_sum   'Ca3 Si6 Sb3'
_cell_volume   272.64
_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  0.0  1.0
  Si  Si1  3  0.0  0.0  0.22  1.0
  Si  Si2  3  0.0  0.0  0.65  1.0
  Sb  Sb3  3  0.0  0.0  0.43  1.0

Ca Si Si Sb
Ca Si Si Sb 0 1 - - - 0 1 - - o 0 1 o - - 0 1 - o - 0 3 - - o 0 3 - o - 0 3 o - - 0 2 - o o 0 2 o - o 0 2 o o - 1 3 o o o 1 3 o o + 1 3 + o o 1 3 o + o 1 2 o o + 1 2 o + o 1 2 + o o 2 3 o - o 2 3 - o o 2 3 o o - 2 3 o o o 
CaSi2Sb is Heusler structured and crystallizes in the trigonal R3m space group. Ca(1) is bonded in a 10-coordinate geometry to three equivalent Si(2), four equivalent Si(1), and three equivalent Sb(1) atoms. All Ca(1)-Si(2) bond lengths are 2.92 Å. There is one shorter (2.67 Å) and three longer (3.26 Å) Ca(1)-Si(1) bond lengths. All Ca(1)-Sb(1) bond lengths are 3.16 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 5-coordinate geometry to four equivalent Ca(1) and one Sb(1) atom. The Si(1)-Sb(1) bond length is 2.67 Å. In the second Si site, Si(2) is bonded to three equivalent Ca(1) and one Sb(1) atom to form corner-sharing SiCa3Sb trigonal pyramids. The Si(2)-Sb(1) bond length is 2.67 Å. Sb(1) is bonded in a 5-coordinate geometry to three equivalent Ca(1), one Si(1), and one Si(2) atom.