data_GdMg2As
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.11
_cell_length_b   5.11
_cell_length_c   5.11
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   GdMg2As
_chemical_formula_sum   'Gd1 Mg2 As1'
_cell_volume   94.25
_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
  Gd  Gd1  1  0.61  0.61  0.61  1.0
  Mg  Mg2  1  0.42  0.42  0.42  1.0
  Mg  Mg3  1  0.81  0.81  0.81  1.0
  As  As0  1  0.0  0.0  0.0  1.0

data_GdMg2As
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.11
_cell_length_b   5.11
_cell_length_c   12.51
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   GdMg2As
_chemical_formula_sum   'Gd3 Mg6 As3'
_cell_volume   282.75
_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
  Gd  Gd0  3  0.0  0.0  0.39  1.0
  Mg  Mg1  3  0.0  0.0  0.19  1.0
  Mg  Mg2  3  0.0  0.0  0.58  1.0
  As  As3  3  0.0  0.0  -0.0  1.0

Gd Mg Mg As
Mg2GdAs crystallizes in the trigonal R3m space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one Gd(1) and three equivalent As(1) atoms to form distorted corner-sharing MgGdAs3 tetrahedra. The Mg(1)-Gd(1) bond length is 2.43 Å. All Mg(1)-As(1) bond lengths are 3.13 Å. In the second Mg site, Mg(2) is bonded in a distorted linear geometry to one Gd(1) and one As(1) atom. The Mg(2)-Gd(1) bond length is 2.43 Å. The Mg(2)-As(1) bond length is 2.43 Å. Gd(1) is bonded in a 5-coordinate geometry to one Mg(1), one Mg(2), and three equivalent As(1) atoms. All Gd(1)-As(1) bond lengths are 3.03 Å. As(1) is bonded in a 7-coordinate geometry to one Mg(2), three equivalent Mg(1), and three equivalent Gd(1) atoms.