data_CaZr
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.07
_cell_length_b   4.07
_cell_length_c   8.18
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   CaZr
_chemical_formula_sum   'Ca2 Zr2'
_cell_volume   135.64
_cell_formula_units_Z   2
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  0.04  0.0  0.81  1.0
  Ca  Ca1  1  0.0  0.04  0.37  1.0
  Zr  Zr2  1  0.04  0.04  0.0  1.0
  Zr  Zr3  1  0.0  0.0  0.0  1.0

data_CaZr
_symmetry_space_group_name_H-M   Cm
_cell_length_a   5.76
_cell_length_b   5.76
_cell_length_c   8.18
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   CaZr
_chemical_formula_sum   'Ca4 Zr4'
_cell_volume   271.27
_cell_formula_units_Z   4
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  0.37  1.0
  Ca  Ca1  2  0.04  0.0  0.81  1.0
  Zr  Zr2  4  0.02  0.02  0.0  1.0

Ca Ca Zr Zr
Ca Ca Zr Zr 0 3 o o + 0 2 o o + 0 1 o o o 1 3 o o o 1 2 o o o 2 3 o o o 
CaZr1 crystallizes in the monoclinic Cm space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 2-coordinate geometry to one Ca(2) and two equivalent Zr(1) atoms. The Ca(1)-Ca(2) bond length is 3.59 Å. Both Ca(1)-Zr(1) bond lengths are 1.56 Å. In the second Ca site, Ca(2) is bonded to one Ca(1), four equivalent Ca(2), and two equivalent Zr(1) atoms to form a mixture of distorted corner and edge-sharing CaCa5Zr2 pentagonal bipyramids. All Ca(2)-Ca(2) bond lengths are 4.07 Å. Both Ca(2)-Zr(1) bond lengths are 3.05 Å. Zr(1) is bonded in a distorted single-bond geometry to one Ca(1), one Ca(2), and one Zr(1) atom. The Zr(1)-Zr(1) bond length is 0.21 Å.