The crystal structure described by K4MgHo2Nb10O30 crystallizes in the orthorhombic Amm2 space group. There are three inequivalent K sites. In the first K site, K(1) is bonded in a 8-coordinate geometry to two equivalent O(4), two equivalent O(6), and four equivalent O(13) atoms. In the second K site, K(2) is bonded in a 7-coordinate geometry to one O(8), two equivalent O(5), and four equivalent O(14) atoms. In the third K site, K(3) is bonded in a 9-coordinate geometry to one O(2), one O(3), one O(9), two equivalent O(16), two equivalent O(17), and two equivalent O(7) atoms. Mg(1) is bonded in a distorted rectangular see-saw-like geometry to two equivalent O(13) and two equivalent O(15) atoms. Ho(1) is bonded in a 9-coordinate geometry to one O(1), one O(3), one O(4), two equivalent O(10), two equivalent O(11), and two equivalent O(12) atoms. There are six inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to two equivalent O(14), two equivalent O(15), and two equivalent O(8) atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 4-14°. In the second Nb site, Nb(2) is bonded to two equivalent O(16), two equivalent O(17), and two equivalent O(9) atoms to form NbO6 octahedra that share corners with two equivalent Nb(2)O6 octahedra, corners with two equivalent Nb(5)O6 octahedra, and corners with two equivalent Nb(6)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 18-35°. In the third Nb site, Nb(3) is bonded in a 6-coordinate geometry to one O(10), one O(12), one O(14), one O(7), and two equivalent O(1) atoms. In the fourth Nb site, Nb(4) is bonded to one O(11), one O(13), one O(15), one O(7), and two equivalent O(2) atoms to form distorted corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 14-25°. In the fifth Nb site, Nb(5) is bonded to one O(11), one O(12), one O(16), one O(5), and two equivalent O(3) atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 15-35°. In the sixth Nb site, Nb(6) is bonded to one O(10), one O(17), one O(6), and two equivalent O(4) atoms to form distorted NbO5 trigonal bipyramids that share  a cornercorner with one Nb(2)O6 octahedra and corners with three equivalent Nb(6)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 39°. There are seventeen inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one Ho(1) and two equivalent Nb(3) atoms. In the second O site, O(2) is bonded in a 2-coordinate geometry to one K(3) and two equivalent Nb(4) atoms. In the third O site, O(3) is bonded in a distorted T-shaped geometry to one K(3), one Ho(1), and two equivalent Nb(5) atoms. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one K(1), one Ho(1), and two equivalent Nb(6) atoms. In the fifth O site, O(5) is bonded in a distorted bent 150 degrees geometry to two equivalent K(2) and two equivalent Nb(5) atoms. In the sixth O site, O(6) is bonded to two equivalent K(1) and two equivalent Nb(6) atoms to form distorted OK2Nb2 tetrahedra that share corners with two equivalent O(10)Ho2Nb2 tetrahedra and corners with two equivalent O(6)K2Nb2 tetrahedra. In the seventh O site, O(7) is bonded in a distorted rectangular see-saw-like geometry to two equivalent K(3), one Nb(3), and one Nb(4) atom. In the eighth O site, O(8) is bonded in a distorted linear geometry to one K(2) and two equivalent Nb(1) atoms. In the ninth O site, O(9) is bonded in a distorted bent 150 degrees geometry to two equivalent K(3) and two equivalent Nb(2) atoms. In the tenth O site, O(10) is bonded to two equivalent Ho(1), one Nb(3), and one Nb(6) atom to form distorted OHo2Nb2 tetrahedra that share  a cornercorner with one O(6)K2Nb2 tetrahedra and corners with two equivalent O(10)Ho2Nb2 tetrahedra. In the eleventh O site, O(11) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Ho(1), one Nb(4), and one Nb(5) atom. In the twelfth O site, O(12) is bonded in a 1-coordinate geometry to two equivalent Ho(1), one Nb(3), and one Nb(5) atom. In the thirteenth O site, O(13) is bonded in a distorted water-like geometry to two equivalent K(1), one Mg(1), and one Nb(4) atom. In the fourteenth O site, O(14) is bonded in a distorted bent 150 degrees geometry to two equivalent K(2), one Nb(1), and one Nb(3) atom. In the fifteenth O site, O(15) is bonded in a T-shaped geometry to one Mg(1), one Nb(1), and one Nb(4) atom. In the sixteenth O site, O(16) is bonded in a 4-coordinate geometry to two equivalent K(3), one Nb(2), and one Nb(5) atom. In the seventeenth O site, O(17) is bonded in a 4-coordinate geometry to two equivalent K(3), one Nb(2), and one Nb(6) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_K4Ho2MgNb10O30
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.945
_cell_length_b   13.006
_cell_length_c   13.006
_cell_angle_alpha   85.697
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   665.415
_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  0.500  0.235  0.735  1.0
  K  K1  1  0.500  0.821  0.321  1.0
  K  K2  1  0.500  0.347  0.195  1.0
  K  K3  1  0.500  0.695  0.847  1.0
  Ho  Ho4  1  0.500  0.998  0.028  1.0
  Ho  Ho5  1  0.500  0.528  0.498  1.0
  Mg  Mg6  1  0.000  0.129  0.629  1.0
  Nb  Nb7  1  0.000  0.977  0.477  1.0
  Nb  Nb8  1  0.000  0.515  0.015  1.0
  Nb  Nb9  1  0.000  0.090  0.211  1.0
  Nb  Nb10  1  0.000  0.944  0.785  1.0
  Nb  Nb11  1  0.000  0.797  0.078  1.0
  Nb  Nb12  1  0.000  0.447  0.730  1.0
  Nb  Nb13  1  0.000  0.230  0.947  1.0
  Nb  Nb14  1  0.000  0.578  0.297  1.0
  Nb  Nb15  1  0.000  0.711  0.590  1.0
  Nb  Nb16  1  0.000  0.285  0.444  1.0
  O  O17  1  0.500  0.080  0.177  1.0
  O  O18  1  0.500  0.922  0.792  1.0
  O  O19  1  0.500  0.813  0.066  1.0
  O  O20  1  0.500  0.436  0.690  1.0
  O  O21  1  0.500  0.190  0.936  1.0
  O  O22  1  0.500  0.566  0.313  1.0
  O  O23  1  0.500  0.677  0.580  1.0
  O  O24  1  0.500  0.292  0.422  1.0
  O  O25  1  0.000  0.710  0.210  1.0
  O  O26  1  0.000  0.314  0.814  1.0
  O  O27  1  0.000  0.775  0.713  1.0
  O  O28  1  0.000  0.213  0.275  1.0
  O  O29  1  0.500  0.973  0.473  1.0
  O  O30  1  0.500  0.499  0.999  1.0
  O  O31  1  0.000  0.099  0.042  1.0
  O  O32  1  0.000  0.906  0.938  1.0
  O  O33  1  0.000  0.929  0.137  1.0
  O  O34  1  0.000  0.284  0.592  1.0
  O  O35  1  0.000  0.092  0.784  1.0
  O  O36  1  0.000  0.637  0.429  1.0
  O  O37  1  0.000  0.542  0.599  1.0
  O  O38  1  0.000  0.438  0.406  1.0
  O  O39  1  0.000  0.990  0.322  1.0
  O  O40  1  0.000  0.979  0.630  1.0
  O  O41  1  0.000  0.663  0.001  1.0
  O  O42  1  0.000  0.528  0.839  1.0
  O  O43  1  0.000  0.339  0.028  1.0
  O  O44  1  0.000  0.501  0.163  1.0
  O  O45  1  0.000  0.822  0.490  1.0
  O  O46  1  0.000  0.130  0.479  1.0
[/CIF]
.
The crystal structure described by K4MgHo2Nb10O30 crystallizes in the orthorhombic Amm2 space group. There are three inequivalent K sites. In the first K site, K(1) is bonded in a 8-coordinate geometry to two equivalent O(4), two equivalent O(6), and four equivalent O(13) atoms. In the second K site, K(2) is bonded in a 7-coordinate geometry to one O(8), two equivalent O(5), and four equivalent O(14) atoms. In the third K site, K(3) is bonded in a 9-coordinate geometry to one O(2), one O(3), one O(9), two equivalent O(16), two equivalent O(17), and two equivalent O(7) atoms. Mg(1) is bonded in a distorted rectangular see-saw-like geometry to two equivalent O(13) and two equivalent O(15) atoms. Ho(1) is bonded in a 9-coordinate geometry to one O(1), one O(3), one O(4), two equivalent O(10), two equivalent O(11), and two equivalent O(12) atoms. There are six inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to two equivalent O(14), two equivalent O(15), and two equivalent O(8) atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 4-14°. In the second Nb site, Nb(2) is bonded to two equivalent O(16), two equivalent O(17), and two equivalent O(9) atoms to form NbO6 octahedra that share corners with two equivalent Nb(2)O6 octahedra, corners with two equivalent Nb(5)O6 octahedra, and corners with two equivalent Nb(6)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 18-35°. In the third Nb site, Nb(3) is bonded in a 6-coordinate geometry to one O(10), one O(12), one O(14), one O(7), and two equivalent O(1) atoms. In the fourth Nb site, Nb(4) is bonded to one O(11), one O(13), one O(15), one O(7), and two equivalent O(2) atoms to form distorted corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 14-25°. In the fifth Nb site, Nb(5) is bonded to one O(11), one O(12), one O(16), one O(5), and two equivalent O(3) atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 15-35°. In the sixth Nb site, Nb(6) is bonded to one O(10), one O(17), one O(6), and two equivalent O(4) atoms to form distorted NbO5 trigonal bipyramids that share  a cornercorner with one Nb(2)O6 octahedra and corners with three equivalent Nb(6)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 39°. There are seventeen inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one Ho(1) and two equivalent Nb(3) atoms. In the second O site, O(2) is bonded in a 2-coordinate geometry to one K(3) and two equivalent Nb(4) atoms. In the third O site, O(3) is bonded in a distorted T-shaped geometry to one K(3), one Ho(1), and two equivalent Nb(5) atoms. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one K(1), one Ho(1), and two equivalent Nb(6) atoms. In the fifth O site, O(5) is bonded in a distorted bent 150 degrees geometry to two equivalent K(2) and two equivalent Nb(5) atoms. In the sixth O site, O(6) is bonded to two equivalent K(1) and two equivalent Nb(6) atoms to form distorted OK2Nb2 tetrahedra that share corners with two equivalent O(10)Ho2Nb2 tetrahedra and corners with two equivalent O(6)K2Nb2 tetrahedra. In the seventh O site, O(7) is bonded in a distorted rectangular see-saw-like geometry to two equivalent K(3), one Nb(3), and one Nb(4) atom. In the eighth O site, O(8) is bonded in a distorted linear geometry to one K(2) and two equivalent Nb(1) atoms. In the ninth O site, O(9) is bonded in a distorted bent 150 degrees geometry to two equivalent K(3) and two equivalent Nb(2) atoms. In the tenth O site, O(10) is bonded to two equivalent Ho(1), one Nb(3), and one Nb(6) atom to form distorted OHo2Nb2 tetrahedra that share  a cornercorner with one O(6)K2Nb2 tetrahedra and corners with two equivalent O(10)Ho2Nb2 tetrahedra. In the eleventh O site, O(11) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Ho(1), one Nb(4), and one Nb(5) atom. In the twelfth O site, O(12) is bonded in a 1-coordinate geometry to two equivalent Ho(1), one Nb(3), and one Nb(5) atom. In the thirteenth O site, O(13) is bonded in a distorted water-like geometry to two equivalent K(1), one Mg(1), and one Nb(4) atom. In the fourteenth O site, O(14) is bonded in a distorted bent 150 degrees geometry to two equivalent K(2), one Nb(1), and one Nb(3) atom. In the fifteenth O site, O(15) is bonded in a T-shaped geometry to one Mg(1), one Nb(1), and one Nb(4) atom. In the sixteenth O site, O(16) is bonded in a 4-coordinate geometry to two equivalent K(3), one Nb(2), and one Nb(5) atom. In the seventeenth O site, O(17) is bonded in a 4-coordinate geometry to two equivalent K(3), one Nb(2), and one Nb(6) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_K4Ho2MgNb10O30
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.945
_cell_length_b   13.006
_cell_length_c   13.006
_cell_angle_alpha   85.697
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   665.415
_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  0.500  0.235  0.735  1.0
  K  K1  1  0.500  0.821  0.321  1.0
  K  K2  1  0.500  0.347  0.195  1.0
  K  K3  1  0.500  0.695  0.847  1.0
  Ho  Ho4  1  0.500  0.998  0.028  1.0
  Ho  Ho5  1  0.500  0.528  0.498  1.0
  Mg  Mg6  1  0.000  0.129  0.629  1.0
  Nb  Nb7  1  0.000  0.977  0.477  1.0
  Nb  Nb8  1  0.000  0.515  0.015  1.0
  Nb  Nb9  1  0.000  0.090  0.211  1.0
  Nb  Nb10  1  0.000  0.944  0.785  1.0
  Nb  Nb11  1  0.000  0.797  0.078  1.0
  Nb  Nb12  1  0.000  0.447  0.730  1.0
  Nb  Nb13  1  0.000  0.230  0.947  1.0
  Nb  Nb14  1  0.000  0.578  0.297  1.0
  Nb  Nb15  1  0.000  0.711  0.590  1.0
  Nb  Nb16  1  0.000  0.285  0.444  1.0
  O  O17  1  0.500  0.080  0.177  1.0
  O  O18  1  0.500  0.922  0.792  1.0
  O  O19  1  0.500  0.813  0.066  1.0
  O  O20  1  0.500  0.436  0.690  1.0
  O  O21  1  0.500  0.190  0.936  1.0
  O  O22  1  0.500  0.566  0.313  1.0
  O  O23  1  0.500  0.677  0.580  1.0
  O  O24  1  0.500  0.292  0.422  1.0
  O  O25  1  0.000  0.710  0.210  1.0
  O  O26  1  0.000  0.314  0.814  1.0
  O  O27  1  0.000  0.775  0.713  1.0
  O  O28  1  0.000  0.213  0.275  1.0
  O  O29  1  0.500  0.973  0.473  1.0
  O  O30  1  0.500  0.499  0.999  1.0
  O  O31  1  0.000  0.099  0.042  1.0
  O  O32  1  0.000  0.906  0.938  1.0
  O  O33  1  0.000  0.929  0.137  1.0
  O  O34  1  0.000  0.284  0.592  1.0
  O  O35  1  0.000  0.092  0.784  1.0
  O  O36  1  0.000  0.637  0.429  1.0
  O  O37  1  0.000  0.542  0.599  1.0
  O  O38  1  0.000  0.438  0.406  1.0
  O  O39  1  0.000  0.990  0.322  1.0
  O  O40  1  0.000  0.979  0.630  1.0
  O  O41  1  0.000  0.663  0.001  1.0
  O  O42  1  0.000  0.528  0.839  1.0
  O  O43  1  0.000  0.339  0.028  1.0
  O  O44  1  0.000  0.501  0.163  1.0
  O  O45  1  0.000  0.822  0.490  1.0
  O  O46  1  0.000  0.130  0.479  1.0
[/CIF]
.