The compound described by K4MgHo2Nb10O30 crystallizes in the monoclinic Pm space group. There are four inequivalent K sites. In the first K site, K(1) is bonded in a 9-coordinate geometry to one O(13), one O(4), one O(5), two equivalent O(10), two equivalent O(24), and two equivalent O(30) atoms. In the second K site, K(2) is bonded in a 7-coordinate geometry to one O(3), two equivalent O(17), two equivalent O(23), and two equivalent O(9) atoms. In the third K site, K(3) is bonded in a 8-coordinate geometry to one O(1), one O(14), two equivalent O(12), two equivalent O(27), and two equivalent O(28) atoms. In the fourth K site, K(4) is bonded in a 10-coordinate geometry to one O(14), one O(7), two equivalent O(11), two equivalent O(21), two equivalent O(25), and two equivalent O(26) atoms. Mg(1) is bonded in a 9-coordinate geometry to one O(13), one O(2), one O(7), two equivalent O(11), two equivalent O(24), and two equivalent O(29) atoms. There are two inequivalent Ho sites. In the first Ho site, Ho(1) is bonded in a 9-coordinate geometry to one O(1), one O(2), one O(5), two equivalent O(15), two equivalent O(16), and two equivalent O(19) atoms. In the second Ho site, Ho(2) is bonded in a 9-coordinate geometry to one O(4), one O(6), one O(8), two equivalent O(18), two equivalent O(20), and two equivalent O(22) atoms. There are ten inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(23), one O(24), one O(29), one O(30), and two equivalent O(13) atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 10-24°. In the second Nb site, Nb(2) is bonded to one O(25), one O(26), one O(27), one O(28), and two equivalent O(14) atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 9-42°. In the third Nb site, Nb(3) is bonded to one O(12), one O(15), one O(17), one O(23), and two equivalent O(1) atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 11-21°. In the fourth Nb site, Nb(4) is bonded to one O(11), one O(16), one O(19), one O(24), and two equivalent O(2) atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 8-32°. In the fifth Nb site, Nb(5) is bonded to one O(16), one O(17), one O(25), one O(9), and two equivalent O(3) atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 7-38°. In the sixth Nb site, Nb(6) is bonded to one O(10), one O(18), one O(21), one O(26), and two equivalent O(4) atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 18-34°. In the seventh Nb site, Nb(7) is bonded to one O(10), one O(15), one O(19), one O(27), and two equivalent O(5) atoms to form distorted corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 8-42°. In the eighth Nb site, Nb(8) is bonded to one O(20), one O(22), one O(28), one O(9), and two equivalent O(6) atoms to form distorted corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 24-38°. In the ninth Nb site, Nb(9) is bonded to one O(11), one O(20), one O(21), one O(29), and two equivalent O(7) atoms to form distorted corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 10-29°. In the tenth Nb site, Nb(10) is bonded in a 6-coordinate geometry to one O(12), one O(18), one O(22), one O(30), and two equivalent O(8) atoms. There are thirty inequivalent O sites. In the first O site, O(1) is bonded in a distorted linear geometry to one K(3), one Ho(1), and two equivalent Nb(3) atoms. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Mg(1), one Ho(1), and two equivalent Nb(4) atoms. In the third O site, O(3) is bonded in a linear geometry to one K(2) and two equivalent Nb(5) atoms. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to one K(1), one Ho(2), and two equivalent Nb(6) atoms. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one K(1), one Ho(1), and two equivalent Nb(7) atoms. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Ho(2) and two equivalent Nb(8) atoms. In the seventh O site, O(7) is bonded in a distorted T-shaped geometry to one K(4), one Mg(1), and two equivalent Nb(9) atoms. In the eighth O site, O(8) is bonded in a distorted T-shaped geometry to one Ho(2) and two equivalent Nb(10) atoms. In the ninth O site, O(9) is bonded in a distorted rectangular see-saw-like geometry to two equivalent K(2), one Nb(5), and one Nb(8) atom. In the tenth O site, O(10) is bonded in a 4-coordinate geometry to two equivalent K(1), one Nb(6), and one Nb(7) atom. In the eleventh O site, O(11) is bonded in a 6-coordinate geometry to two equivalent K(4), two equivalent Mg(1), one Nb(4), and one Nb(9) atom. In the twelfth O site, O(12) is bonded in a 4-coordinate geometry to two equivalent K(3), one Nb(10), and one Nb(3) atom. In the thirteenth O site, O(13) is bonded in a distorted T-shaped geometry to one K(1), one Mg(1), and two equivalent Nb(1) atoms. In the fourteenth O site, O(14) is bonded in a distorted linear geometry to one K(3), one K(4), and two equivalent Nb(2) atoms. In the fifteenth O site, O(15) is bonded in a distorted see-saw-like geometry to two equivalent Ho(1), one Nb(3), and one Nb(7) atom. In the sixteenth O site, O(16) 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 seventeenth O site, O(17) is bonded in a 4-coordinate geometry to two equivalent K(2), one Nb(3), and one Nb(5) atom. In the eighteenth O site, O(18) is bonded in a distorted see-saw-like geometry to two equivalent Ho(2), one Nb(10), and one Nb(6) atom. In the nineteenth O site, O(19) is bonded in a distorted see-saw-like geometry to two equivalent Ho(1), one Nb(4), and one Nb(7) atom. In the twentieth O site, O(20) is bonded in a 4-coordinate geometry to two equivalent Ho(2), one Nb(8), and one Nb(9) atom. In the twenty-first O site, O(21) is bonded in a distorted bent 150 degrees geometry to two equivalent K(4), one Nb(6), and one Nb(9) atom. In the twenty-second O site, O(22) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Ho(2), one Nb(10), and one Nb(8) atom. In the twenty-third O site, O(23) is bonded in a distorted bent 150 degrees geometry to two equivalent K(2), one Nb(1), and one Nb(3) atom. In the twenty-fourth O site, O(24) is bonded in a 2-coordinate geometry to two equivalent K(1), two equivalent Mg(1), one Nb(1), and one Nb(4) atom. In the twenty-fifth O site, O(25) is bonded in a distorted bent 150 degrees geometry to two equivalent K(4), one Nb(2), and one Nb(5) atom. In the twenty-sixth O site, O(26) is bonded in a 2-coordinate geometry to two equivalent K(4), one Nb(2), and one Nb(6) atom. In the twenty-seventh O site, O(27) is bonded in a distorted rectangular see-saw-like geometry to two equivalent K(3), one Nb(2), and one Nb(7) atom. In the twenty-eighth O site, O(28) is bonded in a distorted bent 150 degrees geometry to two equivalent K(3), one Nb(2), and one Nb(8) atom. In the twenty-ninth O site, O(29) is bonded in a see-saw-like geometry to two equivalent Mg(1), one Nb(1), and one Nb(9) atom. In the thirtieth O site, O(30) is bonded in a 4-coordinate geometry to two equivalent K(1), one Nb(1), and one Nb(10) atom. is represented by the CIF file [CIF]
data_K4Ho2MgNb10O30
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.970
_cell_length_b   12.901
_cell_length_c   12.931
_cell_angle_alpha   89.086
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   662.279
_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  0.179  0.663  1.0
  K  K1  1  0.500  0.839  0.300  1.0
  K  K2  1  0.500  0.325  0.155  1.0
  K  K3  1  0.500  0.655  0.820  1.0
  Ho  Ho4  1  0.500  0.024  0.972  1.0
  Ho  Ho5  1  0.500  0.466  0.475  1.0
  Mg  Mg6  1  0.500  0.874  0.607  1.0
  Nb  Nb7  1  0.000  0.010  0.493  1.0
  Nb  Nb8  1  0.000  0.499  0.992  1.0
  Nb  Nb9  1  0.000  0.058  0.196  1.0
  Nb  Nb10  1  0.000  0.926  0.793  1.0
  Nb  Nb11  1  0.000  0.783  0.069  1.0
  Nb  Nb12  1  0.000  0.429  0.700  1.0
  Nb  Nb13  1  0.000  0.222  0.913  1.0
  Nb  Nb14  1  0.000  0.571  0.278  1.0
  Nb  Nb15  1  0.000  0.697  0.572  1.0
  Nb  Nb16  1  0.000  0.277  0.403  1.0
  O  O17  1  0.500  0.069  0.187  1.0
  O  O18  1  0.500  0.935  0.809  1.0
  O  O19  1  0.500  0.792  0.071  1.0
  O  O20  1  0.500  0.428  0.676  1.0
  O  O21  1  0.500  0.193  0.918  1.0
  O  O22  1  0.500  0.568  0.320  1.0
  O  O23  1  0.500  0.720  0.588  1.0
  O  O24  1  0.500  0.300  0.427  1.0
  O  O25  1  0.000  0.706  0.215  1.0
  O  O26  1  0.000  0.291  0.778  1.0
  O  O27  1  0.000  0.796  0.725  1.0
  O  O28  1  0.000  0.212  0.277  1.0
  O  O29  1  0.500  0.996  0.510  1.0
  O  O30  1  0.500  0.496  0.003  1.0
  O  O31  1  0.000  0.113  0.051  1.0
  O  O32  1  0.000  0.892  0.954  1.0
  O  O33  1  0.000  0.917  0.162  1.0
  O  O34  1  0.000  0.394  0.549  1.0
  O  O35  1  0.000  0.071  0.863  1.0
  O  O36  1  0.000  0.610  0.456  1.0
  O  O37  1  0.000  0.582  0.668  1.0
  O  O38  1  0.000  0.427  0.359  1.0
  O  O39  1  0.000  0.006  0.347  1.0
  O  O40  1  0.000  0.997  0.659  1.0
  O  O41  1  0.000  0.656  0.992  1.0
  O  O42  1  0.000  0.490  0.846  1.0
  O  O43  1  0.000  0.336  0.004  1.0
  O  O44  1  0.000  0.497  0.157  1.0
  O  O45  1  0.000  0.848  0.519  1.0
  O  O46  1  0.000  0.162  0.505  1.0
[/CIF]
.
The compound described by K4MgHo2Nb10O30 crystallizes in the monoclinic Pm space group. There are four inequivalent K sites. In the first K site, K(1) is bonded in a 9-coordinate geometry to one O(13), one O(4), one O(5), two equivalent O(10), two equivalent O(24), and two equivalent O(30) atoms. In the second K site, K(2) is bonded in a 7-coordinate geometry to one O(3), two equivalent O(17), two equivalent O(23), and two equivalent O(9) atoms. In the third K site, K(3) is bonded in a 8-coordinate geometry to one O(1), one O(14), two equivalent O(12), two equivalent O(27), and two equivalent O(28) atoms. In the fourth K site, K(4) is bonded in a 10-coordinate geometry to one O(14), one O(7), two equivalent O(11), two equivalent O(21), two equivalent O(25), and two equivalent O(26) atoms. Mg(1) is bonded in a 9-coordinate geometry to one O(13), one O(2), one O(7), two equivalent O(11), two equivalent O(24), and two equivalent O(29) atoms. There are two inequivalent Ho sites. In the first Ho site, Ho(1) is bonded in a 9-coordinate geometry to one O(1), one O(2), one O(5), two equivalent O(15), two equivalent O(16), and two equivalent O(19) atoms. In the second Ho site, Ho(2) is bonded in a 9-coordinate geometry to one O(4), one O(6), one O(8), two equivalent O(18), two equivalent O(20), and two equivalent O(22) atoms. There are ten inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(23), one O(24), one O(29), one O(30), and two equivalent O(13) atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 10-24°. In the second Nb site, Nb(2) is bonded to one O(25), one O(26), one O(27), one O(28), and two equivalent O(14) atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 9-42°. In the third Nb site, Nb(3) is bonded to one O(12), one O(15), one O(17), one O(23), and two equivalent O(1) atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 11-21°. In the fourth Nb site, Nb(4) is bonded to one O(11), one O(16), one O(19), one O(24), and two equivalent O(2) atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 8-32°. In the fifth Nb site, Nb(5) is bonded to one O(16), one O(17), one O(25), one O(9), and two equivalent O(3) atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 7-38°. In the sixth Nb site, Nb(6) is bonded to one O(10), one O(18), one O(21), one O(26), and two equivalent O(4) atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 18-34°. In the seventh Nb site, Nb(7) is bonded to one O(10), one O(15), one O(19), one O(27), and two equivalent O(5) atoms to form distorted corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 8-42°. In the eighth Nb site, Nb(8) is bonded to one O(20), one O(22), one O(28), one O(9), and two equivalent O(6) atoms to form distorted corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 24-38°. In the ninth Nb site, Nb(9) is bonded to one O(11), one O(20), one O(21), one O(29), and two equivalent O(7) atoms to form distorted corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 10-29°. In the tenth Nb site, Nb(10) is bonded in a 6-coordinate geometry to one O(12), one O(18), one O(22), one O(30), and two equivalent O(8) atoms. There are thirty inequivalent O sites. In the first O site, O(1) is bonded in a distorted linear geometry to one K(3), one Ho(1), and two equivalent Nb(3) atoms. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Mg(1), one Ho(1), and two equivalent Nb(4) atoms. In the third O site, O(3) is bonded in a linear geometry to one K(2) and two equivalent Nb(5) atoms. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to one K(1), one Ho(2), and two equivalent Nb(6) atoms. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one K(1), one Ho(1), and two equivalent Nb(7) atoms. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Ho(2) and two equivalent Nb(8) atoms. In the seventh O site, O(7) is bonded in a distorted T-shaped geometry to one K(4), one Mg(1), and two equivalent Nb(9) atoms. In the eighth O site, O(8) is bonded in a distorted T-shaped geometry to one Ho(2) and two equivalent Nb(10) atoms. In the ninth O site, O(9) is bonded in a distorted rectangular see-saw-like geometry to two equivalent K(2), one Nb(5), and one Nb(8) atom. In the tenth O site, O(10) is bonded in a 4-coordinate geometry to two equivalent K(1), one Nb(6), and one Nb(7) atom. In the eleventh O site, O(11) is bonded in a 6-coordinate geometry to two equivalent K(4), two equivalent Mg(1), one Nb(4), and one Nb(9) atom. In the twelfth O site, O(12) is bonded in a 4-coordinate geometry to two equivalent K(3), one Nb(10), and one Nb(3) atom. In the thirteenth O site, O(13) is bonded in a distorted T-shaped geometry to one K(1), one Mg(1), and two equivalent Nb(1) atoms. In the fourteenth O site, O(14) is bonded in a distorted linear geometry to one K(3), one K(4), and two equivalent Nb(2) atoms. In the fifteenth O site, O(15) is bonded in a distorted see-saw-like geometry to two equivalent Ho(1), one Nb(3), and one Nb(7) atom. In the sixteenth O site, O(16) 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 seventeenth O site, O(17) is bonded in a 4-coordinate geometry to two equivalent K(2), one Nb(3), and one Nb(5) atom. In the eighteenth O site, O(18) is bonded in a distorted see-saw-like geometry to two equivalent Ho(2), one Nb(10), and one Nb(6) atom. In the nineteenth O site, O(19) is bonded in a distorted see-saw-like geometry to two equivalent Ho(1), one Nb(4), and one Nb(7) atom. In the twentieth O site, O(20) is bonded in a 4-coordinate geometry to two equivalent Ho(2), one Nb(8), and one Nb(9) atom. In the twenty-first O site, O(21) is bonded in a distorted bent 150 degrees geometry to two equivalent K(4), one Nb(6), and one Nb(9) atom. In the twenty-second O site, O(22) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Ho(2), one Nb(10), and one Nb(8) atom. In the twenty-third O site, O(23) is bonded in a distorted bent 150 degrees geometry to two equivalent K(2), one Nb(1), and one Nb(3) atom. In the twenty-fourth O site, O(24) is bonded in a 2-coordinate geometry to two equivalent K(1), two equivalent Mg(1), one Nb(1), and one Nb(4) atom. In the twenty-fifth O site, O(25) is bonded in a distorted bent 150 degrees geometry to two equivalent K(4), one Nb(2), and one Nb(5) atom. In the twenty-sixth O site, O(26) is bonded in a 2-coordinate geometry to two equivalent K(4), one Nb(2), and one Nb(6) atom. In the twenty-seventh O site, O(27) is bonded in a distorted rectangular see-saw-like geometry to two equivalent K(3), one Nb(2), and one Nb(7) atom. In the twenty-eighth O site, O(28) is bonded in a distorted bent 150 degrees geometry to two equivalent K(3), one Nb(2), and one Nb(8) atom. In the twenty-ninth O site, O(29) is bonded in a see-saw-like geometry to two equivalent Mg(1), one Nb(1), and one Nb(9) atom. In the thirtieth O site, O(30) is bonded in a 4-coordinate geometry to two equivalent K(1), one Nb(1), and one Nb(10) atom. is represented by the CIF file [CIF]
data_K4Ho2MgNb10O30
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.970
_cell_length_b   12.901
_cell_length_c   12.931
_cell_angle_alpha   89.086
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   662.279
_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  0.179  0.663  1.0
  K  K1  1  0.500  0.839  0.300  1.0
  K  K2  1  0.500  0.325  0.155  1.0
  K  K3  1  0.500  0.655  0.820  1.0
  Ho  Ho4  1  0.500  0.024  0.972  1.0
  Ho  Ho5  1  0.500  0.466  0.475  1.0
  Mg  Mg6  1  0.500  0.874  0.607  1.0
  Nb  Nb7  1  0.000  0.010  0.493  1.0
  Nb  Nb8  1  0.000  0.499  0.992  1.0
  Nb  Nb9  1  0.000  0.058  0.196  1.0
  Nb  Nb10  1  0.000  0.926  0.793  1.0
  Nb  Nb11  1  0.000  0.783  0.069  1.0
  Nb  Nb12  1  0.000  0.429  0.700  1.0
  Nb  Nb13  1  0.000  0.222  0.913  1.0
  Nb  Nb14  1  0.000  0.571  0.278  1.0
  Nb  Nb15  1  0.000  0.697  0.572  1.0
  Nb  Nb16  1  0.000  0.277  0.403  1.0
  O  O17  1  0.500  0.069  0.187  1.0
  O  O18  1  0.500  0.935  0.809  1.0
  O  O19  1  0.500  0.792  0.071  1.0
  O  O20  1  0.500  0.428  0.676  1.0
  O  O21  1  0.500  0.193  0.918  1.0
  O  O22  1  0.500  0.568  0.320  1.0
  O  O23  1  0.500  0.720  0.588  1.0
  O  O24  1  0.500  0.300  0.427  1.0
  O  O25  1  0.000  0.706  0.215  1.0
  O  O26  1  0.000  0.291  0.778  1.0
  O  O27  1  0.000  0.796  0.725  1.0
  O  O28  1  0.000  0.212  0.277  1.0
  O  O29  1  0.500  0.996  0.510  1.0
  O  O30  1  0.500  0.496  0.003  1.0
  O  O31  1  0.000  0.113  0.051  1.0
  O  O32  1  0.000  0.892  0.954  1.0
  O  O33  1  0.000  0.917  0.162  1.0
  O  O34  1  0.000  0.394  0.549  1.0
  O  O35  1  0.000  0.071  0.863  1.0
  O  O36  1  0.000  0.610  0.456  1.0
  O  O37  1  0.000  0.582  0.668  1.0
  O  O38  1  0.000  0.427  0.359  1.0
  O  O39  1  0.000  0.006  0.347  1.0
  O  O40  1  0.000  0.997  0.659  1.0
  O  O41  1  0.000  0.656  0.992  1.0
  O  O42  1  0.000  0.490  0.846  1.0
  O  O43  1  0.000  0.336  0.004  1.0
  O  O44  1  0.000  0.497  0.157  1.0
  O  O45  1  0.000  0.848  0.519  1.0
  O  O46  1  0.000  0.162  0.505  1.0
[/CIF]
.