data_Ca3Pb
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.53
_cell_length_b   12.53
_cell_length_c   12.53
_cell_angle_alpha   17.65
_cell_angle_beta   17.65
_cell_angle_gamma   17.65
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ca3Pb
_chemical_formula_sum   'Ca3 Pb1'
_cell_volume   157.64
_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  0.23  1.0
  Ca  Ca1  1  0.0  0.0  0.0  1.0
  Ca  Ca2  1  0.0  0.0  0.76  1.0
  Pb  Pb3  1  0.0  0.0  0.49  1.0

data_Ca3Pb
_symmetry_space_group_name_H-M   Cm
_cell_length_a   6.66
_cell_length_b   3.84
_cell_length_c   12.53
_cell_angle_alpha   90.0
_cell_angle_beta   100.2
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   Ca3Pb
_chemical_formula_sum   'Ca6 Pb2'
_cell_volume   315.28
_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  2  0.0  0.0  0.0  1.0
  Ca  Ca1  2  0.0  0.0  0.77  1.0
  Ca  Ca2  2  0.0  0.0  0.24  1.0
  Pb  Pb3  2  0.0  0.0  0.51  1.0

Ca Ca Ca Pb
Ca3Pb crystallizes in the monoclinic Cm space group. There are four inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a distorted single-bond geometry to one Ca(2) and one Pb(1) atom. The Ca(1)-Ca(2) bond length is 2.84 Å. The Ca(1)-Pb(1) bond length is 3.33 Å. In the second Ca site, Ca(2) is bonded in a distorted linear geometry to one Ca(1); one Ca(3); and six Ca(2,2) atoms. The Ca(2)-Ca(3) bond length is 3.03 Å. All Ca(2)-Ca(2,2) bond lengths are 3.84 Å. In the third Ca site, Ca(3) is bonded in a distorted single-bond geometry to one Ca(2) and one Pb(1) atom. The Ca(3)-Pb(1) bond length is 3.33 Å. In the fourth Ca site, Ca(2) is bonded in a distorted linear geometry to one Ca(1); one Ca(3); and six Ca(2,2) atoms. The Ca(2)-Ca(1) bond length is 2.84 Å. The Ca(2)-Ca(3) bond length is 3.03 Å. Both Ca(2)-Ca(2) bond lengths are 3.84 Å. Pb(1) is bonded in a linear geometry to one Ca(1) and one Ca(3) atom.