data_PaCr3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.86
_cell_length_b   4.86
_cell_length_c   4.86
_cell_angle_alpha   133.44
_cell_angle_beta   133.44
_cell_angle_gamma   67.96
_symmetry_Int_Tables_number   1
_chemical_formula_structural   PaCr3
_chemical_formula_sum   'Pa1 Cr3'
_cell_volume   59.42
_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
  Pa  Pa3  1  0.0  0.0  0.03  1.0
  Cr  Cr0  1  0.92  0.0  0.01  1.0
  Cr  Cr1  1  0.0  0.92  0.01  1.0
  Cr  Cr2  1  0.0  0.0  0.0  1.0

data_PaCr3
_symmetry_space_group_name_H-M   Cm
_cell_length_a   5.43
_cell_length_b   5.43
_cell_length_c   4.86
_cell_angle_alpha   90.0
_cell_angle_beta   123.98
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   PaCr3
_chemical_formula_sum   'Pa2 Cr6'
_cell_volume   118.84
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  'x, -y, z'
  3  'x+1/2, y+1/2, z'
  4  'x+1/2, -y+1/2, 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
  Pa  Pa0  2  0.47  0.5  0.97  1.0
  Cr  Cr1  4  0.45  0.46  0.91  1.0
  Cr  Cr2  2  0.0  0.0  0.0  1.0

Pa Cr Cr Cr
PaCr3 crystallizes in the monoclinic Cm space group. The structure is zero-dimensional and consists of two PaCr3 clusters. Pa(1) is bonded in a 3-coordinate geometry to one Cr(2) and two equivalent Cr(1) atoms. The Pa(1)-Cr(2) bond length is 0.14 Å. Both Pa(1)-Cr(1) bond lengths are 0.34 Å. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded in a single-bond geometry to one Pa(1) atom. In the second Cr site, Cr(2) is bonded in a single-bond geometry to one Pa(1) atom.