data_Nb2NiAs
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.09
_cell_length_b   5.09
_cell_length_c   4.47
_cell_angle_alpha   114.92
_cell_angle_beta   114.92
_cell_angle_gamma   37.3
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Nb2NiAs
_chemical_formula_sum   'Nb2 Ni1 As1'
_cell_volume   62.94
_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
  Nb  Nb1  1  0.58  0.0  0.89  1.0
  Nb  Nb2  1  0.79  0.0  0.1  1.0
  Ni  Ni3  1  0.02  0.0  0.02  1.0
  As  As0  1  0.75  0.0  0.01  1.0

data_Nb2NiAs
_symmetry_space_group_name_H-M   P1
_cell_length_a   3.26
_cell_length_b   4.47
_cell_length_c   5.09
_cell_angle_alpha   114.92
_cell_angle_beta   108.65
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Nb2NiAs
_chemical_formula_sum   'Nb2 Ni1 As1'
_cell_volume   62.94
_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
  Nb  Nb0  1  0.0  0.1  0.79  1.0
  Nb  Nb1  1  0.0  0.89  0.58  1.0
  Ni  Ni2  1  0.0  0.02  0.02  1.0
  As  As3  1  0.0  0.01  0.75  1.0

Nb Nb Ni As
Nb Nb Ni As 0 3 o o + 1 3 o o o 1 2 + o o 2 3 - o o 
Nb2NiAs crystallizes in the triclinic P1 space group. The structure is zero-dimensional and consists of one Nb2NiAs cluster. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a single-bond geometry to one As(1) atom. The Nb(1)-As(1) bond length is 0.81 Å. In the second Nb site, Nb(2) is bonded in a single-bond geometry to one Ni(1) and one As(1) atom. The Nb(2)-Ni(1) bond length is 1.31 Å. The Nb(2)-As(1) bond length is 0.36 Å. Ni(1) is bonded in a 2-coordinate geometry to one Nb(2) and one As(1) atom. The Ni(1)-As(1) bond length is 1.34 Å. As(1) is bonded in a distorted single-bond geometry to one Nb(1), one Nb(2), and one Ni(1) atom.