The crystal structure described by Sr2Zn2As3 crystallizes in the monoclinic C2/m space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded to one As(2), two equivalent As(1), and three equivalent As(3) atoms to form distorted SrAs6 octahedra that share corners with three equivalent Zn(1)Sr2As4 tetrahedra, corners with four equivalent Zn(2)SrAs4 tetrahedra, edges with four equivalent Sr(1)As6 octahedra, edges with two equivalent Zn(2)SrAs4 tetrahedra, and edges with three equivalent Zn(1)Sr2As4 tetrahedra. In the second Sr site, Sr(2) is bonded in a 10-coordinate geometry to one Zn(2), two equivalent Zn(1), three equivalent As(2), and four equivalent As(1) atoms. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded to two equivalent Sr(2), one As(1), one As(2), and two equivalent As(3) atoms to form distorted ZnSr2As4 tetrahedra that share corners with three equivalent Sr(1)As6 octahedra, corners with two equivalent Zn(2)SrAs4 tetrahedra, edges with three equivalent Sr(1)As6 octahedra, edges with two equivalent Zn(1)Sr2As4 tetrahedra, and faces with two equivalent Zn(2)SrAs4 tetrahedra. The corner-sharing octahedral tilt angles range from 20-49°. In the second Zn site, Zn(2) is bonded to one Sr(2), two equivalent As(2), and two equivalent As(3) atoms to form distorted ZnSrAs4 tetrahedra that share corners with four equivalent Sr(1)As6 octahedra, corners with two equivalent Zn(1)Sr2As4 tetrahedra, corners with two equivalent Zn(2)SrAs4 tetrahedra, edges with two equivalent Sr(1)As6 octahedra,  an edgeedge with one Zn(2)SrAs4 tetrahedra, and faces with two equivalent Zn(1)Sr2As4 tetrahedra. The corner-sharing octahedral tilt angles range from 26-55°. There are three inequivalent As sites. In the first As site, As(1) is bonded in a 8-coordinate geometry to two equivalent Sr(1), four equivalent Sr(2), one Zn(1), and one As(1) atom. In the second As site, As(2) is bonded in a 7-coordinate geometry to one Sr(1), three equivalent Sr(2), one Zn(1), and two equivalent Zn(2) atoms. In the third As site, As(3) is bonded in a 7-coordinate geometry to three equivalent Sr(1), two equivalent Zn(1), and two equivalent Zn(2) atoms. is represented by the CIF file [CIF]
data_Sr2Zn2As3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.419
_cell_length_b   8.419
_cell_length_c   11.968
_cell_angle_alpha   55.069
_cell_angle_beta   55.069
_cell_angle_gamma   29.478
_symmetry_Int_Tables_number   1
_cell_volume   336.400
_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
  Sr  Sr0  1  0.266  0.266  0.337  1.0
  Sr  Sr1  1  0.734  0.734  0.663  1.0
  Sr  Sr2  1  0.393  0.393  0.950  1.0
  Sr  Sr3  1  0.607  0.607  0.050  1.0
  Zn  Zn4  1  0.038  0.038  0.687  1.0
  Zn  Zn5  1  0.962  0.962  0.313  1.0
  Zn  Zn6  1  0.412  0.412  0.650  1.0
  Zn  Zn7  1  0.588  0.588  0.350  1.0
  As  As8  1  0.075  0.075  0.875  1.0
  As  As9  1  0.925  0.925  0.125  1.0
  As  As10  1  0.150  0.150  0.205  1.0
  As  As11  1  0.850  0.850  0.795  1.0
  As  As12  1  0.391  0.391  0.457  1.0
  As  As13  1  0.609  0.609  0.543  1.0
[/CIF]
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The crystal structure described by Sr2Zn2As3 crystallizes in the monoclinic C2/m space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded to one As(2), two equivalent As(1), and three equivalent As(3) atoms to form distorted SrAs6 octahedra that share corners with three equivalent Zn(1)Sr2As4 tetrahedra, corners with four equivalent Zn(2)SrAs4 tetrahedra, edges with four equivalent Sr(1)As6 octahedra, edges with two equivalent Zn(2)SrAs4 tetrahedra, and edges with three equivalent Zn(1)Sr2As4 tetrahedra. In the second Sr site, Sr(2) is bonded in a 10-coordinate geometry to one Zn(2), two equivalent Zn(1), three equivalent As(2), and four equivalent As(1) atoms. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded to two equivalent Sr(2), one As(1), one As(2), and two equivalent As(3) atoms to form distorted ZnSr2As4 tetrahedra that share corners with three equivalent Sr(1)As6 octahedra, corners with two equivalent Zn(2)SrAs4 tetrahedra, edges with three equivalent Sr(1)As6 octahedra, edges with two equivalent Zn(1)Sr2As4 tetrahedra, and faces with two equivalent Zn(2)SrAs4 tetrahedra. The corner-sharing octahedral tilt angles range from 20-49°. In the second Zn site, Zn(2) is bonded to one Sr(2), two equivalent As(2), and two equivalent As(3) atoms to form distorted ZnSrAs4 tetrahedra that share corners with four equivalent Sr(1)As6 octahedra, corners with two equivalent Zn(1)Sr2As4 tetrahedra, corners with two equivalent Zn(2)SrAs4 tetrahedra, edges with two equivalent Sr(1)As6 octahedra,  an edgeedge with one Zn(2)SrAs4 tetrahedra, and faces with two equivalent Zn(1)Sr2As4 tetrahedra. The corner-sharing octahedral tilt angles range from 26-55°. There are three inequivalent As sites. In the first As site, As(1) is bonded in a 8-coordinate geometry to two equivalent Sr(1), four equivalent Sr(2), one Zn(1), and one As(1) atom. In the second As site, As(2) is bonded in a 7-coordinate geometry to one Sr(1), three equivalent Sr(2), one Zn(1), and two equivalent Zn(2) atoms. In the third As site, As(3) is bonded in a 7-coordinate geometry to three equivalent Sr(1), two equivalent Zn(1), and two equivalent Zn(2) atoms. is represented by the CIF file [CIF]
data_Sr2Zn2As3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.419
_cell_length_b   8.419
_cell_length_c   11.968
_cell_angle_alpha   55.069
_cell_angle_beta   55.069
_cell_angle_gamma   29.478
_symmetry_Int_Tables_number   1
_cell_volume   336.400
_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
  Sr  Sr0  1  0.266  0.266  0.337  1.0
  Sr  Sr1  1  0.734  0.734  0.663  1.0
  Sr  Sr2  1  0.393  0.393  0.950  1.0
  Sr  Sr3  1  0.607  0.607  0.050  1.0
  Zn  Zn4  1  0.038  0.038  0.687  1.0
  Zn  Zn5  1  0.962  0.962  0.313  1.0
  Zn  Zn6  1  0.412  0.412  0.650  1.0
  Zn  Zn7  1  0.588  0.588  0.350  1.0
  As  As8  1  0.075  0.075  0.875  1.0
  As  As9  1  0.925  0.925  0.125  1.0
  As  As10  1  0.150  0.150  0.205  1.0
  As  As11  1  0.850  0.850  0.795  1.0
  As  As12  1  0.391  0.391  0.457  1.0
  As  As13  1  0.609  0.609  0.543  1.0
[/CIF]
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