data_Er2GaAs
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.03
_cell_length_b   5.03
_cell_length_c   5.03
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Er2GaAs
_chemical_formula_sum   'Er2 Ga1 As1'
_cell_volume   89.99
_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
  Er  Er1  1  0.78  0.78  0.78  1.0
  Er  Er2  1  0.34  0.34  0.34  1.0
  Ga  Ga3  1  0.0  0.0  0.0  1.0
  As  As0  1  0.56  0.56  0.56  1.0

data_Er2GaAs
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.03
_cell_length_b   5.03
_cell_length_c   12.32
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   Er2GaAs
_chemical_formula_sum   'Er6 Ga3 As3'
_cell_volume   269.97
_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
  Er  Er0  3  0.0  0.0  0.22  1.0
  Er  Er1  3  0.0  0.0  0.66  1.0
  Ga  Ga2  3  0.0  0.0  0.0  1.0
  As  As3  3  0.0  0.0  0.44  1.0

Er Er Ga As
Er Er Ga As 0 2 + o + 0 2 o + + 0 2 + + o 0 2 + + + 0 3 o o o 0 3 o o + 0 3 + o o 0 3 o + o 0 1 o o + 0 1 o + o 0 1 + o o 1 3 o - o 1 3 - o o 1 3 o o - 1 3 o o o 1 2 o o + 1 2 o + o 1 2 + o o 2 3 - - o 2 3 - o - 2 3 o - - 
Er2GaAs is Heusler structured and crystallizes in the trigonal R3m space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded in a 8-coordinate geometry to four equivalent Ga(1) and four equivalent As(1) atoms. There is one shorter (2.73 Å) and three longer (3.21 Å) Er(1)-Ga(1) bond lengths. There is one shorter (2.73 Å) and three longer (3.21 Å) Er(1)-As(1) bond lengths. In the second Er site, Er(2) is bonded in a 7-coordinate geometry to three equivalent Ga(1) and four equivalent As(1) atoms. All Er(2)-Ga(1) bond lengths are 2.90 Å. There is one shorter (2.73 Å) and three longer (3.21 Å) Er(2)-As(1) bond lengths. Ga(1) is bonded in a 7-coordinate geometry to three equivalent Er(2) and four equivalent Er(1) atoms. As(1) is bonded in a distorted body-centered cubic geometry to four equivalent Er(1) and four equivalent Er(2) atoms.