data_Ca2ZnAs
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.22
_cell_length_b   5.22
_cell_length_c   5.22
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ca2ZnAs
_chemical_formula_sum   'Ca2 Zn1 As1'
_cell_volume   100.86
_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  Ca1  1  0.54  0.54  0.54  1.0
  Ca  Ca2  1  0.0  0.0  0.0  1.0
  Zn  Zn3  1  0.69  0.69  0.69  1.0
  As  As0  1  0.85  0.85  0.85  1.0

data_Ca2ZnAs
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.22
_cell_length_b   5.22
_cell_length_c   12.8
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   Ca2ZnAs
_chemical_formula_sum   'Ca6 Zn3 As3'
_cell_volume   302.59
_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
  Ca  Ca1  3  0.0  0.0  0.46  1.0
  Zn  Zn2  3  0.0  0.0  0.31  1.0
  As  As3  3  0.0  0.0  0.15  1.0

Ca Ca Zn As
Ca2ZnAs crystallizes in the trigonal R3m space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to one Zn(1) and three equivalent As(1) atoms to form distorted corner-sharing CaZnAs3 trigonal pyramids. The Ca(1)-Zn(1) bond length is 1.95 Å. All Ca(1)-As(1) bond lengths are 3.04 Å. In the second Ca site, Ca(2) is bonded in a distorted single-bond geometry to one As(1) atom. The Ca(2)-As(1) bond length is 1.95 Å. Zn(1) is bonded in a distorted linear geometry to one Ca(1) and one As(1) atom. The Zn(1)-As(1) bond length is 1.95 Å. As(1) is bonded in a distorted linear geometry to one Ca(2), three equivalent Ca(1), and one Zn(1) atom.