The crystal structure described by Er2NiAs2 crystallizes in the hexagonal P6_3/mmc space group. Er(1) is bonded in a 9-coordinate geometry to three equivalent Ni(1), three equivalent As(1), and three equivalent As(2) atoms. Ni(1) is bonded in a 9-coordinate geometry to six equivalent Er(1) and three equivalent As(2) atoms. There are two inequivalent As sites. In the first As site, As(2) is bonded in a 9-coordinate geometry to six equivalent Er(1) and three equivalent Ni(1) atoms. In the second As site, As(1) is bonded to six equivalent Er(1) atoms to form edge-sharing AsEr6 octahedra. is represented by the CIF file [CIF]
data_Er2NiAs2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.053
_cell_length_b   4.053
_cell_length_c   14.031
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   199.616
_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
  Er  Er0  1  0.333  0.667  0.382  1.0
  Er  Er1  1  0.667  0.333  0.618  1.0
  Er  Er2  1  0.667  0.333  0.882  1.0
  Er  Er3  1  0.333  0.667  0.118  1.0
  Ni  Ni4  1  0.000  0.000  0.250  1.0
  Ni  Ni5  1  0.000  0.000  0.750  1.0
  As  As6  1  0.000  0.000  0.500  1.0
  As  As7  1  0.000  0.000  0.000  1.0
  As  As8  1  0.333  0.667  0.750  1.0
  As  As9  1  0.667  0.333  0.250  1.0
[/CIF]
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The crystal structure described by Er2NiAs2 crystallizes in the hexagonal P6_3/mmc space group. Er(1) is bonded in a 9-coordinate geometry to three equivalent Ni(1), three equivalent As(1), and three equivalent As(2) atoms. Ni(1) is bonded in a 9-coordinate geometry to six equivalent Er(1) and three equivalent As(2) atoms. There are two inequivalent As sites. In the first As site, As(2) is bonded in a 9-coordinate geometry to six equivalent Er(1) and three equivalent Ni(1) atoms. In the second As site, As(1) is bonded to six equivalent Er(1) atoms to form edge-sharing AsEr6 octahedra. is represented by the CIF file [CIF]
data_Er2NiAs2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.053
_cell_length_b   4.053
_cell_length_c   14.031
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   199.616
_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
  Er  Er0  1  0.333  0.667  0.382  1.0
  Er  Er1  1  0.667  0.333  0.618  1.0
  Er  Er2  1  0.667  0.333  0.882  1.0
  Er  Er3  1  0.333  0.667  0.118  1.0
  Ni  Ni4  1  0.000  0.000  0.250  1.0
  Ni  Ni5  1  0.000  0.000  0.750  1.0
  As  As6  1  0.000  0.000  0.500  1.0
  As  As7  1  0.000  0.000  0.000  1.0
  As  As8  1  0.333  0.667  0.750  1.0
  As  As9  1  0.667  0.333  0.250  1.0
[/CIF]
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