data_ErNp2U
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.16
_cell_length_b   5.16
_cell_length_c   5.16
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   ErNp2U
_chemical_formula_sum   'Er1 Np2 U1'
_cell_volume   97.35
_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  Er0  1  0.0  0.0  0.0  1.0
  Np  Np1  1  0.48  0.48  0.48  1.0
  Np  Np2  1  0.83  0.83  0.83  1.0
  U  U3  1  0.65  0.65  0.65  1.0

data_ErNp2U
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.16
_cell_length_b   5.16
_cell_length_c   12.65
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   ErNp2U
_chemical_formula_sum   'Er3 Np6 U3'
_cell_volume   292.06
_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  0.0  1.0
  Np  Np1  3  0.0  0.0  0.17  1.0
  Np  Np2  3  0.0  0.0  0.52  1.0
  U  U3  3  0.0  0.0  0.35  1.0

Er Np Np U
Np2UEr crystallizes in the trigonal R3m space group. There are two inequivalent Np sites. In the first Np site, Np(1) is bonded in a distorted single-bond geometry to one U(1) atom. The Np(1)-U(1) bond length is 2.21 Å. In the second Np site, Np(2) is bonded in a distorted linear geometry to one U(1) and one Er(1) atom. The Np(2)-U(1) bond length is 2.21 Å. The Np(2)-Er(1) bond length is 2.21 Å. U(1) is bonded to one Np(1), one Np(2), and three equivalent Er(1) atoms to form distorted corner-sharing UEr3Np2 trigonal bipyramids. All U(1)-Er(1) bond lengths are 2.99 Å. Er(1) is bonded in a 1-coordinate geometry to one Np(2) and three equivalent U(1) atoms.