data_Ca2CoSi2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.73
_cell_length_b   6.73
_cell_length_c   6.73
_cell_angle_alpha   140.91
_cell_angle_beta   140.91
_cell_angle_gamma   56.48
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ca2CoSi2
_chemical_formula_sum   'Ca2 Co1 Si2'
_cell_volume   120.21
_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  0.25  0.96  1.0
  Ca  Ca1  1  0.25  0.0  0.96  1.0
  Co  Co2  1  0.0  0.0  0.0  1.0
  Si  Si3  1  0.0  0.0  0.83  1.0
  Si  Si4  1  0.0  0.0  0.02  1.0

data_Ca2CoSi2
_symmetry_space_group_name_H-M   Cm
_cell_length_a   6.37
_cell_length_b   6.37
_cell_length_c   6.73
_cell_angle_alpha   90.0
_cell_angle_beta   118.24
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   Ca2CoSi2
_chemical_formula_sum   'Ca4 Co2 Si4'
_cell_volume   240.43
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  'x, -y, z'
  3  'x+1/2, y+1/2, z'
  4  'x+1/2, -y+1/2, 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  4  0.13  0.13  0.29  1.0
  Co  Co1  2  0.0  0.0  0.0  1.0
  Si  Si2  2  0.0  0.0  0.17  1.0
  Si  Si3  2  0.0  0.0  0.98  1.0

Ca Ca Co Si Si
Ca Ca Co Si Si 0 3 o o o 1 3 o o o 2 4 o o o 2 3 o o - 3 4 o o + 
Ca2CoSi2 is Indium-like structured and crystallizes in the monoclinic Cm space group. The structure is zero-dimensional and consists of two Ca2CoSi2 clusters. Ca(1) is bonded in a single-bond geometry to one Si(1) atom. The Ca(1)-Si(1) bond length is 1.15 Å. Co(1) is bonded in a distorted linear geometry to one Si(1) and one Si(2) atom. The Co(1)-Si(1) bond length is 1.12 Å. The Co(1)-Si(2) bond length is 0.16 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a distorted L-shaped geometry to two equivalent Ca(1) and one Co(1) atom. In the second Si site, Si(2) is bonded in a single-bond geometry to one Co(1) atom.