The structure described by Mg2ZnAs2 crystallizes in the trigonal P3m1 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to three equivalent As(1) and three equivalent As(2) atoms to form MgAs6 octahedra that share corners with six equivalent Mg(2)Zn3As4 tetrahedra, edges with six equivalent Mg(1)As6 octahedra, and edges with three equivalent Mg(2)Zn3As4 tetrahedra. In the second Mg site, Mg(2) is bonded to three equivalent Zn(1), one As(1), and three equivalent As(2) atoms to form distorted MgZn3As4 tetrahedra that share corners with six equivalent Mg(1)As6 octahedra, corners with six equivalent As(1)Mg4Zn3 pentagonal bipyramids, edges with three equivalent Mg(1)As6 octahedra, edges with six equivalent Mg(2)Zn3As4 tetrahedra, and  a faceface with one As(1)Mg4Zn3 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 11-56°. Zn(1) is bonded in a 7-coordinate geometry to three equivalent Mg(2), one As(2), and three equivalent As(1) atoms. There are two inequivalent As sites. In the first As site, As(1) is bonded to one Mg(2), three equivalent Mg(1), and three equivalent Zn(1) atoms to form distorted AsMg4Zn3 pentagonal bipyramids that share corners with six equivalent Mg(2)Zn3As4 tetrahedra, edges with six equivalent As(1)Mg4Zn3 pentagonal bipyramids, and  a faceface with one Mg(2)Zn3As4 tetrahedra. In the second As site, As(2) is bonded in a 7-coordinate geometry to three equivalent Mg(1), three equivalent Mg(2), and one Zn(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Mg2ZnAs2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.142
_cell_length_b   4.142
_cell_length_c   6.730
_cell_angle_alpha   89.998
_cell_angle_beta   90.000
_cell_angle_gamma   119.999
_symmetry_Int_Tables_number   1
_cell_volume   99.981
_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
  As  As0  1  0.667  0.333  0.762  1.0
  As  As1  1  0.333  0.667  0.231  1.0
  Mg  Mg2  1  1.000  1.000  0.005  1.0
  Mg  Mg3  1  0.667  0.333  0.370  1.0
  Zn  Zn4  1  0.333  0.667  0.632  1.0
[/CIF]
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The structure described by Mg2ZnAs2 crystallizes in the trigonal P3m1 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to three equivalent As(1) and three equivalent As(2) atoms to form MgAs6 octahedra that share corners with six equivalent Mg(2)Zn3As4 tetrahedra, edges with six equivalent Mg(1)As6 octahedra, and edges with three equivalent Mg(2)Zn3As4 tetrahedra. In the second Mg site, Mg(2) is bonded to three equivalent Zn(1), one As(1), and three equivalent As(2) atoms to form distorted MgZn3As4 tetrahedra that share corners with six equivalent Mg(1)As6 octahedra, corners with six equivalent As(1)Mg4Zn3 pentagonal bipyramids, edges with three equivalent Mg(1)As6 octahedra, edges with six equivalent Mg(2)Zn3As4 tetrahedra, and  a faceface with one As(1)Mg4Zn3 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 11-56°. Zn(1) is bonded in a 7-coordinate geometry to three equivalent Mg(2), one As(2), and three equivalent As(1) atoms. There are two inequivalent As sites. In the first As site, As(1) is bonded to one Mg(2), three equivalent Mg(1), and three equivalent Zn(1) atoms to form distorted AsMg4Zn3 pentagonal bipyramids that share corners with six equivalent Mg(2)Zn3As4 tetrahedra, edges with six equivalent As(1)Mg4Zn3 pentagonal bipyramids, and  a faceface with one Mg(2)Zn3As4 tetrahedra. In the second As site, As(2) is bonded in a 7-coordinate geometry to three equivalent Mg(1), three equivalent Mg(2), and one Zn(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Mg2ZnAs2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.142
_cell_length_b   4.142
_cell_length_c   6.730
_cell_angle_alpha   89.998
_cell_angle_beta   90.000
_cell_angle_gamma   119.999
_symmetry_Int_Tables_number   1
_cell_volume   99.981
_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
  As  As0  1  0.667  0.333  0.762  1.0
  As  As1  1  0.333  0.667  0.231  1.0
  Mg  Mg2  1  1.000  1.000  0.005  1.0
  Mg  Mg3  1  0.667  0.333  0.370  1.0
  Zn  Zn4  1  0.333  0.667  0.632  1.0
[/CIF]
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