The material structure described by UNiAs2 is Parent of FeAs superconductors-derived structured and crystallizes in the tetragonal P4/nmm space group. U(1) is bonded to four equivalent Ni(1), four equivalent As(1), and four equivalent As(2) atoms to form UNi4As8 cuboctahedra that share corners with four equivalent U(1)Ni4As8 cuboctahedra, corners with eight equivalent Ni(1)U4As4 tetrahedra, edges with eight equivalent U(1)Ni4As8 cuboctahedra, edges with four equivalent Ni(1)U4As4 tetrahedra, and faces with four equivalent U(1)Ni4As8 cuboctahedra. Ni(1) is bonded to four equivalent U(1) and four equivalent As(2) atoms to form distorted NiU4As4 tetrahedra that share corners with eight equivalent U(1)Ni4As8 cuboctahedra, edges with four equivalent U(1)Ni4As8 cuboctahedra, edges with four equivalent Ni(1)U4As4 tetrahedra, and faces with four equivalent Ni(1)U4As4 tetrahedra. There are two inequivalent As sites. In the first As site, As(1) is bonded in a 8-coordinate geometry to four equivalent U(1) and four equivalent As(1) atoms. In the second As site, As(2) is bonded in a 8-coordinate geometry to four equivalent U(1) and four equivalent Ni(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_UNiAs2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.006
_cell_length_b   4.006
_cell_length_c   9.062
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   145.393
_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
  U  U0  1  0.500  0.000  0.750  1.0
  U  U1  1  0.000  0.500  0.250  1.0
  Ni  Ni2  1  0.500  0.500  0.500  1.0
  Ni  Ni3  1  0.000  0.000  0.500  1.0
  As  As4  1  0.500  0.500  0.000  1.0
  As  As5  1  0.000  0.500  0.650  1.0
  As  As6  1  0.000  0.000  0.000  1.0
  As  As7  1  0.500  0.000  0.350  1.0
[/CIF]
.
The material structure described by UNiAs2 is Parent of FeAs superconductors-derived structured and crystallizes in the tetragonal P4/nmm space group. U(1) is bonded to four equivalent Ni(1), four equivalent As(1), and four equivalent As(2) atoms to form UNi4As8 cuboctahedra that share corners with four equivalent U(1)Ni4As8 cuboctahedra, corners with eight equivalent Ni(1)U4As4 tetrahedra, edges with eight equivalent U(1)Ni4As8 cuboctahedra, edges with four equivalent Ni(1)U4As4 tetrahedra, and faces with four equivalent U(1)Ni4As8 cuboctahedra. Ni(1) is bonded to four equivalent U(1) and four equivalent As(2) atoms to form distorted NiU4As4 tetrahedra that share corners with eight equivalent U(1)Ni4As8 cuboctahedra, edges with four equivalent U(1)Ni4As8 cuboctahedra, edges with four equivalent Ni(1)U4As4 tetrahedra, and faces with four equivalent Ni(1)U4As4 tetrahedra. There are two inequivalent As sites. In the first As site, As(1) is bonded in a 8-coordinate geometry to four equivalent U(1) and four equivalent As(1) atoms. In the second As site, As(2) is bonded in a 8-coordinate geometry to four equivalent U(1) and four equivalent Ni(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_UNiAs2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.006
_cell_length_b   4.006
_cell_length_c   9.062
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   145.393
_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
  U  U0  1  0.500  0.000  0.750  1.0
  U  U1  1  0.000  0.500  0.250  1.0
  Ni  Ni2  1  0.500  0.500  0.500  1.0
  Ni  Ni3  1  0.000  0.000  0.500  1.0
  As  As4  1  0.500  0.500  0.000  1.0
  As  As5  1  0.000  0.500  0.650  1.0
  As  As6  1  0.000  0.000  0.000  1.0
  As  As7  1  0.500  0.000  0.350  1.0
[/CIF]
.