data_Er2BAs
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.79
_cell_length_b   4.79
_cell_length_c   4.79
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Er2BAs
_chemical_formula_sum   'Er2 B1 As1'
_cell_volume   77.92
_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  Er2  1  0.7  0.7  0.7  1.0
  Er  Er3  1  0.09  0.09  0.09  1.0
  B  B1  1  0.0  0.0  0.0  1.0
  As  As0  1  0.39  0.39  0.39  1.0

data_Er2BAs
_symmetry_space_group_name_H-M   R3m
_cell_length_a   4.79
_cell_length_b   4.79
_cell_length_c   11.74
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   Er2BAs
_chemical_formula_sum   'Er6 B3 As3'
_cell_volume   233.75
_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
  Er  Er0  3  0.0  0.0  0.3  1.0
  Er  Er1  3  0.0  0.0  0.91  1.0
  B  B2  3  0.0  0.0  0.0  1.0
  As  As3  3  0.0  0.0  0.61  1.0

Er Er B As
Er2BAs crystallizes in the trigonal R3m space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded in a 7-coordinate geometry to three equivalent B(1) and four equivalent As(1) atoms. All Er(1)-B(1) bond lengths are 2.79 Å. There are three shorter (2.79 Å) and one longer (3.58 Å) Er(1)-As(1) bond length. In the second Er site, Er(2) is bonded in a single-bond geometry to one B(1) and four equivalent As(1) atoms. The Er(2)-B(1) bond length is 1.00 Å. There are three shorter (2.79 Å) and one longer (3.58 Å) Er(2)-As(1) bond length. B(1) is bonded in a single-bond geometry to one Er(2) and three equivalent Er(1) atoms. As(1) is bonded to four equivalent Er(1) and four equivalent Er(2) atoms to form distorted edge-sharing AsEr8 hexagonal bipyramids.