The compound described by K2Nb4Fe2O13 crystallizes in the monoclinic C2/m space group. K(1) is bonded in a 6-coordinate geometry to two equivalent O(4), two equivalent O(5), and two equivalent O(7) atoms. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(5), one O(6), one O(7), and three equivalent O(3) atoms to form a mixture of distorted edge and corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles are 33°. In the second Nb site, Nb(2) is bonded to one O(2), one O(4), one O(5), one O(6), and two equivalent O(1) atoms to form a mixture of distorted edge and corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 0-16°. Fe(1) is bonded in a 6-coordinate geometry to one O(1), one O(3), one O(4), one O(7), and two equivalent O(6) atoms. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to two equivalent Nb(2) and one Fe(1) atom. In the second O site, O(2) is bonded in a linear geometry to two equivalent Nb(2) atoms. In the third O site, O(3) is bonded to three equivalent Nb(1) and one Fe(1) atom to form distorted ONb3Fe trigonal pyramids that share  a cornercorner with one O(6)Nb2Fe2 tetrahedra, corners with two equivalent O(3)Nb3Fe trigonal pyramids, edges with two equivalent O(6)Nb2Fe2 tetrahedra, and edges with two equivalent O(3)Nb3Fe trigonal pyramids. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to two equivalent K(1), one Nb(2), and one Fe(1) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to two equivalent K(1), one Nb(1), and one Nb(2) atom. In the sixth O site, O(6) is bonded to one Nb(1), one Nb(2), and two equivalent Fe(1) atoms to form ONb2Fe2 tetrahedra that share corners with two equivalent O(6)Nb2Fe2 tetrahedra,  a cornercorner with one O(3)Nb3Fe trigonal pyramid, and edges with two equivalent O(3)Nb3Fe trigonal pyramids. In the seventh O site, O(7) is bonded in a distorted rectangular see-saw-like geometry to two equivalent K(1), one Nb(1), and one Fe(1) atom. is represented by the CIF file [CIF]
data_K2Nb4Fe2O13
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.433
_cell_length_b   8.433
_cell_length_c   9.636
_cell_angle_alpha   80.028
_cell_angle_beta   80.028
_cell_angle_gamma   27.170
_symmetry_Int_Tables_number   1
_cell_volume   307.881
_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  K0  1  0.551  0.551  0.749  1.0
  K  K1  1  0.449  0.449  0.251  1.0
  Nb  Nb2  1  0.836  0.836  0.936  1.0
  Nb  Nb3  1  0.881  0.881  0.585  1.0
  Nb  Nb4  1  0.164  0.164  0.064  1.0
  Nb  Nb5  1  0.119  0.119  0.415  1.0
  Fe  Fe6  1  0.763  0.763  0.275  1.0
  Fe  Fe7  1  0.237  0.237  0.725  1.0
  O  O8  1  0.624  0.624  0.386  1.0
  O  O9  1  0.376  0.376  0.614  1.0
  O  O10  1  0.000  0.000  0.500  1.0
  O  O11  1  0.700  0.700  0.062  1.0
  O  O12  1  0.300  0.300  0.938  1.0
  O  O13  1  0.164  0.164  0.577  1.0
  O  O14  1  0.836  0.836  0.423  1.0
  O  O15  1  0.068  0.068  0.197  1.0
  O  O16  1  0.777  0.777  0.743  1.0
  O  O17  1  0.223  0.223  0.257  1.0
  O  O18  1  0.932  0.932  0.803  1.0
  O  O19  1  0.131  0.131  0.890  1.0
  O  O20  1  0.869  0.869  0.110  1.0
[/CIF]
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The compound described by K2Nb4Fe2O13 crystallizes in the monoclinic C2/m space group. K(1) is bonded in a 6-coordinate geometry to two equivalent O(4), two equivalent O(5), and two equivalent O(7) atoms. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(5), one O(6), one O(7), and three equivalent O(3) atoms to form a mixture of distorted edge and corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles are 33°. In the second Nb site, Nb(2) is bonded to one O(2), one O(4), one O(5), one O(6), and two equivalent O(1) atoms to form a mixture of distorted edge and corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 0-16°. Fe(1) is bonded in a 6-coordinate geometry to one O(1), one O(3), one O(4), one O(7), and two equivalent O(6) atoms. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to two equivalent Nb(2) and one Fe(1) atom. In the second O site, O(2) is bonded in a linear geometry to two equivalent Nb(2) atoms. In the third O site, O(3) is bonded to three equivalent Nb(1) and one Fe(1) atom to form distorted ONb3Fe trigonal pyramids that share  a cornercorner with one O(6)Nb2Fe2 tetrahedra, corners with two equivalent O(3)Nb3Fe trigonal pyramids, edges with two equivalent O(6)Nb2Fe2 tetrahedra, and edges with two equivalent O(3)Nb3Fe trigonal pyramids. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to two equivalent K(1), one Nb(2), and one Fe(1) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to two equivalent K(1), one Nb(1), and one Nb(2) atom. In the sixth O site, O(6) is bonded to one Nb(1), one Nb(2), and two equivalent Fe(1) atoms to form ONb2Fe2 tetrahedra that share corners with two equivalent O(6)Nb2Fe2 tetrahedra,  a cornercorner with one O(3)Nb3Fe trigonal pyramid, and edges with two equivalent O(3)Nb3Fe trigonal pyramids. In the seventh O site, O(7) is bonded in a distorted rectangular see-saw-like geometry to two equivalent K(1), one Nb(1), and one Fe(1) atom. is represented by the CIF file [CIF]
data_K2Nb4Fe2O13
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.433
_cell_length_b   8.433
_cell_length_c   9.636
_cell_angle_alpha   80.028
_cell_angle_beta   80.028
_cell_angle_gamma   27.170
_symmetry_Int_Tables_number   1
_cell_volume   307.881
_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  K0  1  0.551  0.551  0.749  1.0
  K  K1  1  0.449  0.449  0.251  1.0
  Nb  Nb2  1  0.836  0.836  0.936  1.0
  Nb  Nb3  1  0.881  0.881  0.585  1.0
  Nb  Nb4  1  0.164  0.164  0.064  1.0
  Nb  Nb5  1  0.119  0.119  0.415  1.0
  Fe  Fe6  1  0.763  0.763  0.275  1.0
  Fe  Fe7  1  0.237  0.237  0.725  1.0
  O  O8  1  0.624  0.624  0.386  1.0
  O  O9  1  0.376  0.376  0.614  1.0
  O  O10  1  0.000  0.000  0.500  1.0
  O  O11  1  0.700  0.700  0.062  1.0
  O  O12  1  0.300  0.300  0.938  1.0
  O  O13  1  0.164  0.164  0.577  1.0
  O  O14  1  0.836  0.836  0.423  1.0
  O  O15  1  0.068  0.068  0.197  1.0
  O  O16  1  0.777  0.777  0.743  1.0
  O  O17  1  0.223  0.223  0.257  1.0
  O  O18  1  0.932  0.932  0.803  1.0
  O  O19  1  0.131  0.131  0.890  1.0
  O  O20  1  0.869  0.869  0.110  1.0
[/CIF]
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