data_KFeAs2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.03
_cell_length_b   3.03
_cell_length_c   8.07
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   KFeAs2
_chemical_formula_sum   'K1 Fe1 As2'
_cell_volume   74.24
_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
  K  K3  1  0.0  0.0  0.0  1.0
  Fe  Fe2  1  0.0  0.0  0.04  1.0
  As  As0  1  0.52  0.52  0.61  1.0
  As  As1  1  0.52  0.52  0.46  1.0

data_KFeAs2
_symmetry_space_group_name_H-M   Cm
_cell_length_a   4.29
_cell_length_b   4.29
_cell_length_c   8.07
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   KFeAs2
_chemical_formula_sum   'K2 Fe2 As4'
_cell_volume   148.47
_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
  K  K0  2  0.0  0.0  0.0  1.0
  Fe  Fe1  2  0.0  0.0  0.04  1.0
  As  As2  2  0.02  0.5  0.46  1.0
  As  As3  2  0.02  0.5  0.61  1.0

K Fe As As
KFe(As)2 is beta oxygen-derived structured and crystallizes in the monoclinic Cm space group. The structure is zero-dimensional and consists of two diarsene molecules and two iron;potassium molecules.