The compound described by KFe3As4(HO8)2 crystallizes in the monoclinic C2/c space group. K(1) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(3), two equivalent O(4), and two equivalent O(5) atoms. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent O(2), two equivalent O(7), and two equivalent O(8) atoms to form FeO6 octahedra that share corners with four equivalent Fe(2)O6 octahedra, corners with two equivalent As(1)O4 tetrahedra, and corners with four equivalent As(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 51-54°. In the second Fe site, Fe(2) is bonded to one O(1), one O(3), one O(5), one O(6), one O(7), and one O(8) atom to form FeO6 octahedra that share corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent As(1)O4 tetrahedra, corners with two equivalent As(2)O4 tetrahedra, and  an edgeedge with one As(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 51-54°. There are two inequivalent As sites. In the first As site, As(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form AsO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra and corners with two equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 52-56°. In the second As site, As(2) is bonded to one O(5), one O(6), one O(7), and one O(8) atom to form AsO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra, and  an edgeedge with one Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 44-57°. H(1) is bonded in a single-bond geometry to one O(4) atom. There are eight inequivalent O sites. In the first O site, O(7) is bonded in a distorted trigonal planar geometry to one Fe(1), one Fe(2), and one As(2) atom. In the second O site, O(8) is bonded in a distorted trigonal planar geometry to one Fe(1), one Fe(2), and one As(2) atom. In the third O site, O(1) is bonded in a 3-coordinate geometry to one K(1), one Fe(2), and one As(1) atom. In the fourth O site, O(2) is bonded in a bent 120 degrees geometry to one Fe(1) and one As(1) atom. In the fifth O site, O(3) is bonded in a bent 120 degrees geometry to one K(1), one Fe(2), and one As(1) atom. In the sixth O site, O(4) is bonded in a 3-coordinate geometry to one K(1), one As(1), and one H(1) atom. In the seventh O site, O(5) is bonded in a 3-coordinate geometry to one K(1), one Fe(2), and one As(2) atom. In the eighth O site, O(6) is bonded in a distorted bent 150 degrees geometry to one Fe(2) and one As(2) atom. is represented by the CIF file [CIF]
data_KFe3As4(HO8)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.266
_cell_length_b   10.266
_cell_length_c   11.138
_cell_angle_alpha   80.143
_cell_angle_beta   80.143
_cell_angle_gamma   38.024
_symmetry_Int_Tables_number   1
_cell_volume   711.109
_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
  K  K0  1  0.162  0.838  0.250  1.0
  K  K1  1  0.838  0.162  0.750  1.0
  Fe  Fe2  1  0.500  0.000  0.500  1.0
  Fe  Fe3  1  0.000  0.500  0.000  1.0
  Fe  Fe4  1  0.331  0.368  0.225  1.0
  Fe  Fe5  1  0.632  0.669  0.275  1.0
  Fe  Fe6  1  0.669  0.632  0.775  1.0
  Fe  Fe7  1  0.368  0.331  0.725  1.0
  As  As8  1  0.582  0.259  0.448  1.0
  As  As9  1  0.741  0.418  0.052  1.0
  As  As10  1  0.418  0.741  0.552  1.0
  As  As11  1  0.259  0.582  0.948  1.0
  As  As12  1  0.179  0.215  0.270  1.0
  As  As13  1  0.785  0.821  0.230  1.0
  As  As14  1  0.821  0.785  0.730  1.0
  As  As15  1  0.215  0.179  0.770  1.0
  H  H16  1  0.796  0.277  0.403  1.0
  H  H17  1  0.723  0.204  0.097  1.0
  H  H18  1  0.204  0.723  0.597  1.0
  H  H19  1  0.277  0.796  0.903  1.0
  O  O20  1  0.412  0.426  0.334  1.0
  O  O21  1  0.574  0.588  0.166  1.0
  O  O22  1  0.588  0.574  0.666  1.0
  O  O23  1  0.426  0.412  0.834  1.0
  O  O24  1  0.669  0.032  0.465  1.0
  O  O25  1  0.968  0.331  0.035  1.0
  O  O26  1  0.331  0.968  0.535  1.0
  O  O27  1  0.032  0.669  0.965  1.0
  O  O28  1  0.470  0.386  0.581  1.0
  O  O29  1  0.614  0.530  0.919  1.0
  O  O30  1  0.530  0.614  0.419  1.0
  O  O31  1  0.386  0.470  0.081  1.0
  O  O32  1  0.822  0.160  0.410  1.0
  O  O33  1  0.840  0.178  0.090  1.0
  O  O34  1  0.178  0.840  0.590  1.0
  O  O35  1  0.160  0.822  0.910  1.0
  O  O36  1  0.326  0.966  0.252  1.0
  O  O37  1  0.034  0.674  0.248  1.0
  O  O38  1  0.674  0.034  0.748  1.0
  O  O39  1  0.966  0.326  0.752  1.0
  O  O40  1  0.925  0.367  0.315  1.0
  O  O41  1  0.633  0.075  0.185  1.0
  O  O42  1  0.075  0.633  0.685  1.0
  O  O43  1  0.367  0.925  0.815  1.0
  O  O44  1  0.287  0.234  0.363  1.0
  O  O45  1  0.766  0.713  0.137  1.0
  O  O46  1  0.713  0.766  0.637  1.0
  O  O47  1  0.234  0.287  0.863  1.0
  O  O48  1  0.205  0.320  0.139  1.0
  O  O49  1  0.680  0.795  0.361  1.0
  O  O50  1  0.795  0.680  0.861  1.0
  O  O51  1  0.320  0.205  0.639  1.0
[/CIF]
.
The compound described by KFe3As4(HO8)2 crystallizes in the monoclinic C2/c space group. K(1) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(3), two equivalent O(4), and two equivalent O(5) atoms. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent O(2), two equivalent O(7), and two equivalent O(8) atoms to form FeO6 octahedra that share corners with four equivalent Fe(2)O6 octahedra, corners with two equivalent As(1)O4 tetrahedra, and corners with four equivalent As(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 51-54°. In the second Fe site, Fe(2) is bonded to one O(1), one O(3), one O(5), one O(6), one O(7), and one O(8) atom to form FeO6 octahedra that share corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent As(1)O4 tetrahedra, corners with two equivalent As(2)O4 tetrahedra, and  an edgeedge with one As(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 51-54°. There are two inequivalent As sites. In the first As site, As(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form AsO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra and corners with two equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 52-56°. In the second As site, As(2) is bonded to one O(5), one O(6), one O(7), and one O(8) atom to form AsO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra, and  an edgeedge with one Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 44-57°. H(1) is bonded in a single-bond geometry to one O(4) atom. There are eight inequivalent O sites. In the first O site, O(7) is bonded in a distorted trigonal planar geometry to one Fe(1), one Fe(2), and one As(2) atom. In the second O site, O(8) is bonded in a distorted trigonal planar geometry to one Fe(1), one Fe(2), and one As(2) atom. In the third O site, O(1) is bonded in a 3-coordinate geometry to one K(1), one Fe(2), and one As(1) atom. In the fourth O site, O(2) is bonded in a bent 120 degrees geometry to one Fe(1) and one As(1) atom. In the fifth O site, O(3) is bonded in a bent 120 degrees geometry to one K(1), one Fe(2), and one As(1) atom. In the sixth O site, O(4) is bonded in a 3-coordinate geometry to one K(1), one As(1), and one H(1) atom. In the seventh O site, O(5) is bonded in a 3-coordinate geometry to one K(1), one Fe(2), and one As(2) atom. In the eighth O site, O(6) is bonded in a distorted bent 150 degrees geometry to one Fe(2) and one As(2) atom. is represented by the CIF file [CIF]
data_KFe3As4(HO8)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.266
_cell_length_b   10.266
_cell_length_c   11.138
_cell_angle_alpha   80.143
_cell_angle_beta   80.143
_cell_angle_gamma   38.024
_symmetry_Int_Tables_number   1
_cell_volume   711.109
_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
  K  K0  1  0.162  0.838  0.250  1.0
  K  K1  1  0.838  0.162  0.750  1.0
  Fe  Fe2  1  0.500  0.000  0.500  1.0
  Fe  Fe3  1  0.000  0.500  0.000  1.0
  Fe  Fe4  1  0.331  0.368  0.225  1.0
  Fe  Fe5  1  0.632  0.669  0.275  1.0
  Fe  Fe6  1  0.669  0.632  0.775  1.0
  Fe  Fe7  1  0.368  0.331  0.725  1.0
  As  As8  1  0.582  0.259  0.448  1.0
  As  As9  1  0.741  0.418  0.052  1.0
  As  As10  1  0.418  0.741  0.552  1.0
  As  As11  1  0.259  0.582  0.948  1.0
  As  As12  1  0.179  0.215  0.270  1.0
  As  As13  1  0.785  0.821  0.230  1.0
  As  As14  1  0.821  0.785  0.730  1.0
  As  As15  1  0.215  0.179  0.770  1.0
  H  H16  1  0.796  0.277  0.403  1.0
  H  H17  1  0.723  0.204  0.097  1.0
  H  H18  1  0.204  0.723  0.597  1.0
  H  H19  1  0.277  0.796  0.903  1.0
  O  O20  1  0.412  0.426  0.334  1.0
  O  O21  1  0.574  0.588  0.166  1.0
  O  O22  1  0.588  0.574  0.666  1.0
  O  O23  1  0.426  0.412  0.834  1.0
  O  O24  1  0.669  0.032  0.465  1.0
  O  O25  1  0.968  0.331  0.035  1.0
  O  O26  1  0.331  0.968  0.535  1.0
  O  O27  1  0.032  0.669  0.965  1.0
  O  O28  1  0.470  0.386  0.581  1.0
  O  O29  1  0.614  0.530  0.919  1.0
  O  O30  1  0.530  0.614  0.419  1.0
  O  O31  1  0.386  0.470  0.081  1.0
  O  O32  1  0.822  0.160  0.410  1.0
  O  O33  1  0.840  0.178  0.090  1.0
  O  O34  1  0.178  0.840  0.590  1.0
  O  O35  1  0.160  0.822  0.910  1.0
  O  O36  1  0.326  0.966  0.252  1.0
  O  O37  1  0.034  0.674  0.248  1.0
  O  O38  1  0.674  0.034  0.748  1.0
  O  O39  1  0.966  0.326  0.752  1.0
  O  O40  1  0.925  0.367  0.315  1.0
  O  O41  1  0.633  0.075  0.185  1.0
  O  O42  1  0.075  0.633  0.685  1.0
  O  O43  1  0.367  0.925  0.815  1.0
  O  O44  1  0.287  0.234  0.363  1.0
  O  O45  1  0.766  0.713  0.137  1.0
  O  O46  1  0.713  0.766  0.637  1.0
  O  O47  1  0.234  0.287  0.863  1.0
  O  O48  1  0.205  0.320  0.139  1.0
  O  O49  1  0.680  0.795  0.361  1.0
  O  O50  1  0.795  0.680  0.861  1.0
  O  O51  1  0.320  0.205  0.639  1.0
[/CIF]
.