The material described by U2Ni3As4 crystallizes in the tetragonal P4mm space group. There are two inequivalent U sites. In the first U site, U(1) is bonded to four equivalent Ni(1), four equivalent As(2), and four equivalent As(3) atoms to form distorted UNi4As8 cuboctahedra that share corners with four equivalent U(1)Ni4As8 cuboctahedra, corners with eight equivalent Ni(1)U4As4 tetrahedra, edges with four equivalent Ni(1)U4As4 tetrahedra, and faces with four equivalent U(1)Ni4As8 cuboctahedra. In the second U site, U(2) is bonded in a 16-coordinate geometry to four equivalent Ni(1), four equivalent Ni(2), four equivalent As(1), and four equivalent As(3) atoms. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to two equivalent U(1), two equivalent U(2), two equivalent As(1), and two equivalent As(2) atoms to form distorted NiU4As4 tetrahedra that share corners with four equivalent U(1)Ni4As8 cuboctahedra, edges with two equivalent U(1)Ni4As8 cuboctahedra, edges with four equivalent Ni(1)U4As4 tetrahedra, and faces with four equivalent Ni(1)U4As4 tetrahedra. In the second Ni site, Ni(2) is bonded in a 5-coordinate geometry to four equivalent U(2), one As(1), and four equivalent As(3) atoms. There are three inequivalent As sites. In the first As site, As(1) is bonded in a 5-coordinate geometry to four equivalent U(2), one Ni(2), and four equivalent Ni(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. In the third As site, As(3) is bonded in a 10-coordinate geometry to two equivalent U(1), two equivalent U(2), two equivalent Ni(2), and four equivalent As(3) atoms. is represented by the CIF card [CIF]
data_U2Ni3As4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.089
_cell_length_b   4.089
_cell_length_c   9.202
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   153.866
_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
  U  U0  1  0.750  0.750  0.750  1.0
  U  U1  1  0.250  0.250  0.251  1.0
  Ni  Ni2  1  0.750  0.250  0.500  1.0
  Ni  Ni3  1  0.250  0.750  0.500  1.0
  Ni  Ni4  1  0.750  0.750  0.115  1.0
  As  As5  1  0.750  0.750  0.365  1.0
  As  As6  1  0.250  0.250  0.646  1.0
  As  As7  1  0.750  0.250  0.991  1.0
  As  As8  1  0.250  0.750  0.991  1.0
[/CIF]
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The material described by U2Ni3As4 crystallizes in the tetragonal P4mm space group. There are two inequivalent U sites. In the first U site, U(1) is bonded to four equivalent Ni(1), four equivalent As(2), and four equivalent As(3) atoms to form distorted UNi4As8 cuboctahedra that share corners with four equivalent U(1)Ni4As8 cuboctahedra, corners with eight equivalent Ni(1)U4As4 tetrahedra, edges with four equivalent Ni(1)U4As4 tetrahedra, and faces with four equivalent U(1)Ni4As8 cuboctahedra. In the second U site, U(2) is bonded in a 16-coordinate geometry to four equivalent Ni(1), four equivalent Ni(2), four equivalent As(1), and four equivalent As(3) atoms. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to two equivalent U(1), two equivalent U(2), two equivalent As(1), and two equivalent As(2) atoms to form distorted NiU4As4 tetrahedra that share corners with four equivalent U(1)Ni4As8 cuboctahedra, edges with two equivalent U(1)Ni4As8 cuboctahedra, edges with four equivalent Ni(1)U4As4 tetrahedra, and faces with four equivalent Ni(1)U4As4 tetrahedra. In the second Ni site, Ni(2) is bonded in a 5-coordinate geometry to four equivalent U(2), one As(1), and four equivalent As(3) atoms. There are three inequivalent As sites. In the first As site, As(1) is bonded in a 5-coordinate geometry to four equivalent U(2), one Ni(2), and four equivalent Ni(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. In the third As site, As(3) is bonded in a 10-coordinate geometry to two equivalent U(1), two equivalent U(2), two equivalent Ni(2), and four equivalent As(3) atoms. is represented by the CIF card [CIF]
data_U2Ni3As4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.089
_cell_length_b   4.089
_cell_length_c   9.202
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   153.866
_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
  U  U0  1  0.750  0.750  0.750  1.0
  U  U1  1  0.250  0.250  0.251  1.0
  Ni  Ni2  1  0.750  0.250  0.500  1.0
  Ni  Ni3  1  0.250  0.750  0.500  1.0
  Ni  Ni4  1  0.750  0.750  0.115  1.0
  As  As5  1  0.750  0.750  0.365  1.0
  As  As6  1  0.250  0.250  0.646  1.0
  As  As7  1  0.750  0.250  0.991  1.0
  As  As8  1  0.250  0.750  0.991  1.0
[/CIF]
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