The compound described by FeNb2O6 crystallizes in the triclinic P1 space group. There are eight inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(1), one O(13), one O(14), one O(21), one O(22), and one O(5) atom to form distorted NbO6 octahedra that share corners with two equivalent Nb(7)O6 octahedra, corners with two equivalent Nb(8)O6 octahedra, corners with two equivalent Fe(4)O6 octahedra,  an edgeedge with one Fe(2)O6 octahedra, and edges with two equivalent Nb(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 12-55°. In the second Nb site, Nb(2) is bonded to one O(15), one O(18), one O(20), one O(24), one O(8), and one O(9) atom to form distorted NbO6 octahedra that share corners with two equivalent Nb(5)O6 octahedra, corners with two equivalent Nb(6)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra,  an edgeedge with one Fe(3)O6 octahedra, and edges with two equivalent Nb(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-55°. In the third Nb site, Nb(3) is bonded to one O(15), one O(18), one O(19), one O(24), one O(3), and one O(8) atom to form distorted NbO6 octahedra that share corners with two equivalent Nb(5)O6 octahedra, corners with two equivalent Nb(6)O6 octahedra, corners with two equivalent Fe(3)O6 octahedra,  an edgeedge with one Fe(1)O6 octahedra, and edges with two equivalent Nb(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-55°. In the fourth Nb site, Nb(4) is bonded to one O(1), one O(10), one O(14), one O(22), one O(23), and one O(5) atom to form distorted NbO6 octahedra that share corners with two equivalent Nb(7)O6 octahedra, corners with two equivalent Nb(8)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra,  an edgeedge with one Fe(4)O6 octahedra, and edges with two equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 12-55°. In the fifth Nb site, Nb(5) is bonded to one O(11), one O(18), one O(19), one O(2), one O(7), and one O(9) atom to form distorted NbO6 octahedra that share corners with two equivalent Nb(2)O6 octahedra, corners with two equivalent Nb(3)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra,  an edgeedge with one Fe(4)O6 octahedra, and edges with two equivalent Nb(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-55°. In the sixth Nb site, Nb(6) is bonded to one O(11), one O(16), one O(19), one O(7), one O(8), and one O(9) atom to form distorted NbO6 octahedra that share corners with two equivalent Nb(2)O6 octahedra, corners with two equivalent Nb(3)O6 octahedra, corners with two equivalent Fe(4)O6 octahedra,  an edgeedge with one Fe(2)O6 octahedra, and edges with two equivalent Nb(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-55°. In the seventh Nb site, Nb(7) is bonded to one O(12), one O(13), one O(17), one O(23), one O(5), and one O(6) atom to form distorted NbO6 octahedra that share corners with two equivalent Nb(1)O6 octahedra, corners with two equivalent Nb(4)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra,  an edgeedge with one Fe(3)O6 octahedra, and edges with two equivalent Nb(8)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-55°. In the eighth Nb site, Nb(8) is bonded to one O(12), one O(13), one O(17), one O(22), one O(23), and one O(4) atom to form distorted NbO6 octahedra that share corners with two equivalent Nb(1)O6 octahedra, corners with two equivalent Nb(4)O6 octahedra, corners with two equivalent Fe(3)O6 octahedra,  an edgeedge with one Fe(1)O6 octahedra, and edges with two equivalent Nb(7)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-55°. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(12), one O(20), one O(24), one O(3), one O(4), and one O(6) atom to form FeO6 octahedra that share corners with two equivalent Nb(2)O6 octahedra, corners with two equivalent Nb(7)O6 octahedra,  an edgeedge with one Nb(3)O6 octahedra,  an edgeedge with one Nb(8)O6 octahedra, and edges with two equivalent Fe(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-24°. In the second Fe site, Fe(2) is bonded to one O(10), one O(14), one O(16), one O(2), one O(21), and one O(7) atom to form FeO6 octahedra that share corners with two equivalent Nb(4)O6 octahedra, corners with two equivalent Nb(5)O6 octahedra,  an edgeedge with one Nb(1)O6 octahedra,  an edgeedge with one Nb(6)O6 octahedra, and edges with two equivalent Fe(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-26°. In the third Fe site, Fe(3) is bonded to one O(15), one O(17), one O(20), one O(3), one O(4), and one O(6) atom to form FeO6 octahedra that share corners with two equivalent Nb(3)O6 octahedra, corners with two equivalent Nb(8)O6 octahedra,  an edgeedge with one Nb(2)O6 octahedra,  an edgeedge with one Nb(7)O6 octahedra, and edges with two equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-24°. In the fourth Fe site, Fe(4) is bonded to one O(1), one O(10), one O(11), one O(16), one O(2), and one O(21) atom to form FeO6 octahedra that share corners with two equivalent Nb(1)O6 octahedra, corners with two equivalent Nb(6)O6 octahedra,  an edgeedge with one Nb(4)O6 octahedra,  an edgeedge with one Nb(5)O6 octahedra, and edges with two equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-26°. There are twenty-four inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one Nb(1), one Nb(4), and one Fe(4) atom. In the second O site, O(2) is bonded in a T-shaped geometry to one Nb(5), one Fe(2), and one Fe(4) atom. In the third O site, O(3) is bonded in a T-shaped geometry to one Nb(3), one Fe(1), and one Fe(3) atom. In the fourth O site, O(4) is bonded in a T-shaped geometry to one Nb(8), one Fe(1), and one Fe(3) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Nb(1), one Nb(4), and one Nb(7) atom. In the sixth O site, O(6) is bonded in a T-shaped geometry to one Nb(7), one Fe(1), and one Fe(3) atom. In the seventh O site, O(7) is bonded in a distorted T-shaped geometry to one Nb(5), one Nb(6), and one Fe(2) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Nb(2), one Nb(3), and one Nb(6) atom. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Nb(2), one Nb(5), and one Nb(6) atom. In the tenth O site, O(10) is bonded in a T-shaped geometry to one Nb(4), one Fe(2), and one Fe(4) atom. In the eleventh O site, O(11) is bonded in a distorted T-shaped geometry to one Nb(5), one Nb(6), and one Fe(4) atom. In the twelfth O site, O(12) is bonded in a distorted T-shaped geometry to one Nb(7), one Nb(8), and one Fe(1) atom. In the thirteenth O site, O(13) is bonded in a distorted trigonal planar geometry to one Nb(1), one Nb(7), and one Nb(8) atom. In the fourteenth O site, O(14) is bonded in a distorted T-shaped geometry to one Nb(1), one Nb(4), and one Fe(2) atom. In the fifteenth O site, O(15) is bonded in a distorted T-shaped geometry to one Nb(2), one Nb(3), and one Fe(3) atom. In the sixteenth O site, O(16) is bonded in a T-shaped geometry to one Nb(6), one Fe(2), and one Fe(4) atom. In the seventeenth O site, O(17) is bonded in a distorted T-shaped geometry to one Nb(7), one Nb(8), and one Fe(3) atom. In the eighteenth O site, O(18) is bonded in a distorted trigonal planar geometry to one Nb(2), one Nb(3), and one Nb(5) atom. In the nineteenth O site, O(19) is bonded in a distorted trigonal planar geometry to one Nb(3), one Nb(5), and one Nb(6) atom. In the twentieth O site, O(20) is bonded in a T-shaped geometry to one Nb(2), one Fe(1), and one Fe(3) atom. In the twenty-first O site, O(21) is bonded in a T-shaped geometry to one Nb(1), one Fe(2), and one Fe(4) atom. In the twenty-second O site, O(22) is bonded in a distorted trigonal planar geometry to one Nb(1), one Nb(4), and one Nb(8) atom. In the twenty-third O site, O(23) is bonded in a distorted trigonal planar geometry to one Nb(4), one Nb(7), and one Nb(8) atom. In the twenty-fourth O site, O(24) is bonded in a distorted T-shaped geometry to one Nb(2), one Nb(3), and one Fe(1) atom. is represented by the CIF card [CIF]
data_Nb2FeO6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.333
_cell_length_b   5.831
_cell_length_c   14.955
_cell_angle_alpha   89.933
_cell_angle_beta   90.418
_cell_angle_gamma   90.033
_symmetry_Int_Tables_number   1
_cell_volume   465.100
_cell_formula_units_Z   4
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
  Nb  Nb0  1  0.984  0.172  0.165  1.0
  Nb  Nb1  1  0.511  0.669  0.665  1.0
  Nb  Nb2  1  0.011  0.332  0.665  1.0
  Nb  Nb3  1  0.484  0.828  0.165  1.0
  Nb  Nb4  1  0.016  0.829  0.834  1.0
  Nb  Nb5  1  0.516  0.171  0.834  1.0
  Nb  Nb6  1  0.990  0.669  0.335  1.0
  Nb  Nb7  1  0.490  0.331  0.335  1.0
  Fe  Fe8  1  0.750  0.143  0.500  1.0
  Fe  Fe9  1  0.248  0.350  1.000  1.0
  Fe  Fe10  1  0.249  0.857  0.500  1.0
  Fe  Fe11  1  0.748  0.650  1.000  1.0
  O  O12  1  0.796  0.908  0.102  1.0
  O  O13  1  0.092  0.609  0.918  1.0
  O  O14  1  0.091  0.114  0.582  1.0
  O  O15  1  0.409  0.113  0.418  1.0
  O  O16  1  0.161  0.858  0.241  1.0
  O  O17  1  0.909  0.886  0.418  1.0
  O  O18  1  0.205  0.094  0.898  1.0
  O  O19  1  0.337  0.360  0.741  1.0
  O  O20  1  0.340  0.859  0.759  1.0
  O  O21  1  0.408  0.607  0.082  1.0
  O  O22  1  0.705  0.907  0.898  1.0
  O  O23  1  0.806  0.402  0.398  1.0
  O  O24  1  0.163  0.359  0.259  1.0
  O  O25  1  0.296  0.092  0.102  1.0
  O  O26  1  0.194  0.599  0.601  1.0
  O  O27  1  0.592  0.391  0.918  1.0
  O  O28  1  0.306  0.597  0.398  1.0
  O  O29  1  0.837  0.641  0.741  1.0
  O  O30  1  0.840  0.142  0.759  1.0
  O  O31  1  0.591  0.887  0.582  1.0
  O  O32  1  0.908  0.392  0.082  1.0
  O  O33  1  0.661  0.142  0.241  1.0
  O  O34  1  0.663  0.640  0.259  1.0
  O  O35  1  0.694  0.403  0.602  1.0
[/CIF]
.
The compound described by FeNb2O6 crystallizes in the triclinic P1 space group. There are eight inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(1), one O(13), one O(14), one O(21), one O(22), and one O(5) atom to form distorted NbO6 octahedra that share corners with two equivalent Nb(7)O6 octahedra, corners with two equivalent Nb(8)O6 octahedra, corners with two equivalent Fe(4)O6 octahedra,  an edgeedge with one Fe(2)O6 octahedra, and edges with two equivalent Nb(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 12-55°. In the second Nb site, Nb(2) is bonded to one O(15), one O(18), one O(20), one O(24), one O(8), and one O(9) atom to form distorted NbO6 octahedra that share corners with two equivalent Nb(5)O6 octahedra, corners with two equivalent Nb(6)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra,  an edgeedge with one Fe(3)O6 octahedra, and edges with two equivalent Nb(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-55°. In the third Nb site, Nb(3) is bonded to one O(15), one O(18), one O(19), one O(24), one O(3), and one O(8) atom to form distorted NbO6 octahedra that share corners with two equivalent Nb(5)O6 octahedra, corners with two equivalent Nb(6)O6 octahedra, corners with two equivalent Fe(3)O6 octahedra,  an edgeedge with one Fe(1)O6 octahedra, and edges with two equivalent Nb(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-55°. In the fourth Nb site, Nb(4) is bonded to one O(1), one O(10), one O(14), one O(22), one O(23), and one O(5) atom to form distorted NbO6 octahedra that share corners with two equivalent Nb(7)O6 octahedra, corners with two equivalent Nb(8)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra,  an edgeedge with one Fe(4)O6 octahedra, and edges with two equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 12-55°. In the fifth Nb site, Nb(5) is bonded to one O(11), one O(18), one O(19), one O(2), one O(7), and one O(9) atom to form distorted NbO6 octahedra that share corners with two equivalent Nb(2)O6 octahedra, corners with two equivalent Nb(3)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra,  an edgeedge with one Fe(4)O6 octahedra, and edges with two equivalent Nb(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-55°. In the sixth Nb site, Nb(6) is bonded to one O(11), one O(16), one O(19), one O(7), one O(8), and one O(9) atom to form distorted NbO6 octahedra that share corners with two equivalent Nb(2)O6 octahedra, corners with two equivalent Nb(3)O6 octahedra, corners with two equivalent Fe(4)O6 octahedra,  an edgeedge with one Fe(2)O6 octahedra, and edges with two equivalent Nb(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-55°. In the seventh Nb site, Nb(7) is bonded to one O(12), one O(13), one O(17), one O(23), one O(5), and one O(6) atom to form distorted NbO6 octahedra that share corners with two equivalent Nb(1)O6 octahedra, corners with two equivalent Nb(4)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra,  an edgeedge with one Fe(3)O6 octahedra, and edges with two equivalent Nb(8)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-55°. In the eighth Nb site, Nb(8) is bonded to one O(12), one O(13), one O(17), one O(22), one O(23), and one O(4) atom to form distorted NbO6 octahedra that share corners with two equivalent Nb(1)O6 octahedra, corners with two equivalent Nb(4)O6 octahedra, corners with two equivalent Fe(3)O6 octahedra,  an edgeedge with one Fe(1)O6 octahedra, and edges with two equivalent Nb(7)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-55°. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(12), one O(20), one O(24), one O(3), one O(4), and one O(6) atom to form FeO6 octahedra that share corners with two equivalent Nb(2)O6 octahedra, corners with two equivalent Nb(7)O6 octahedra,  an edgeedge with one Nb(3)O6 octahedra,  an edgeedge with one Nb(8)O6 octahedra, and edges with two equivalent Fe(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-24°. In the second Fe site, Fe(2) is bonded to one O(10), one O(14), one O(16), one O(2), one O(21), and one O(7) atom to form FeO6 octahedra that share corners with two equivalent Nb(4)O6 octahedra, corners with two equivalent Nb(5)O6 octahedra,  an edgeedge with one Nb(1)O6 octahedra,  an edgeedge with one Nb(6)O6 octahedra, and edges with two equivalent Fe(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-26°. In the third Fe site, Fe(3) is bonded to one O(15), one O(17), one O(20), one O(3), one O(4), and one O(6) atom to form FeO6 octahedra that share corners with two equivalent Nb(3)O6 octahedra, corners with two equivalent Nb(8)O6 octahedra,  an edgeedge with one Nb(2)O6 octahedra,  an edgeedge with one Nb(7)O6 octahedra, and edges with two equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-24°. In the fourth Fe site, Fe(4) is bonded to one O(1), one O(10), one O(11), one O(16), one O(2), and one O(21) atom to form FeO6 octahedra that share corners with two equivalent Nb(1)O6 octahedra, corners with two equivalent Nb(6)O6 octahedra,  an edgeedge with one Nb(4)O6 octahedra,  an edgeedge with one Nb(5)O6 octahedra, and edges with two equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-26°. There are twenty-four inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one Nb(1), one Nb(4), and one Fe(4) atom. In the second O site, O(2) is bonded in a T-shaped geometry to one Nb(5), one Fe(2), and one Fe(4) atom. In the third O site, O(3) is bonded in a T-shaped geometry to one Nb(3), one Fe(1), and one Fe(3) atom. In the fourth O site, O(4) is bonded in a T-shaped geometry to one Nb(8), one Fe(1), and one Fe(3) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Nb(1), one Nb(4), and one Nb(7) atom. In the sixth O site, O(6) is bonded in a T-shaped geometry to one Nb(7), one Fe(1), and one Fe(3) atom. In the seventh O site, O(7) is bonded in a distorted T-shaped geometry to one Nb(5), one Nb(6), and one Fe(2) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Nb(2), one Nb(3), and one Nb(6) atom. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Nb(2), one Nb(5), and one Nb(6) atom. In the tenth O site, O(10) is bonded in a T-shaped geometry to one Nb(4), one Fe(2), and one Fe(4) atom. In the eleventh O site, O(11) is bonded in a distorted T-shaped geometry to one Nb(5), one Nb(6), and one Fe(4) atom. In the twelfth O site, O(12) is bonded in a distorted T-shaped geometry to one Nb(7), one Nb(8), and one Fe(1) atom. In the thirteenth O site, O(13) is bonded in a distorted trigonal planar geometry to one Nb(1), one Nb(7), and one Nb(8) atom. In the fourteenth O site, O(14) is bonded in a distorted T-shaped geometry to one Nb(1), one Nb(4), and one Fe(2) atom. In the fifteenth O site, O(15) is bonded in a distorted T-shaped geometry to one Nb(2), one Nb(3), and one Fe(3) atom. In the sixteenth O site, O(16) is bonded in a T-shaped geometry to one Nb(6), one Fe(2), and one Fe(4) atom. In the seventeenth O site, O(17) is bonded in a distorted T-shaped geometry to one Nb(7), one Nb(8), and one Fe(3) atom. In the eighteenth O site, O(18) is bonded in a distorted trigonal planar geometry to one Nb(2), one Nb(3), and one Nb(5) atom. In the nineteenth O site, O(19) is bonded in a distorted trigonal planar geometry to one Nb(3), one Nb(5), and one Nb(6) atom. In the twentieth O site, O(20) is bonded in a T-shaped geometry to one Nb(2), one Fe(1), and one Fe(3) atom. In the twenty-first O site, O(21) is bonded in a T-shaped geometry to one Nb(1), one Fe(2), and one Fe(4) atom. In the twenty-second O site, O(22) is bonded in a distorted trigonal planar geometry to one Nb(1), one Nb(4), and one Nb(8) atom. In the twenty-third O site, O(23) is bonded in a distorted trigonal planar geometry to one Nb(4), one Nb(7), and one Nb(8) atom. In the twenty-fourth O site, O(24) is bonded in a distorted T-shaped geometry to one Nb(2), one Nb(3), and one Fe(1) atom. is represented by the CIF card [CIF]
data_Nb2FeO6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.333
_cell_length_b   5.831
_cell_length_c   14.955
_cell_angle_alpha   89.933
_cell_angle_beta   90.418
_cell_angle_gamma   90.033
_symmetry_Int_Tables_number   1
_cell_volume   465.100
_cell_formula_units_Z   4
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
  Nb  Nb0  1  0.984  0.172  0.165  1.0
  Nb  Nb1  1  0.511  0.669  0.665  1.0
  Nb  Nb2  1  0.011  0.332  0.665  1.0
  Nb  Nb3  1  0.484  0.828  0.165  1.0
  Nb  Nb4  1  0.016  0.829  0.834  1.0
  Nb  Nb5  1  0.516  0.171  0.834  1.0
  Nb  Nb6  1  0.990  0.669  0.335  1.0
  Nb  Nb7  1  0.490  0.331  0.335  1.0
  Fe  Fe8  1  0.750  0.143  0.500  1.0
  Fe  Fe9  1  0.248  0.350  1.000  1.0
  Fe  Fe10  1  0.249  0.857  0.500  1.0
  Fe  Fe11  1  0.748  0.650  1.000  1.0
  O  O12  1  0.796  0.908  0.102  1.0
  O  O13  1  0.092  0.609  0.918  1.0
  O  O14  1  0.091  0.114  0.582  1.0
  O  O15  1  0.409  0.113  0.418  1.0
  O  O16  1  0.161  0.858  0.241  1.0
  O  O17  1  0.909  0.886  0.418  1.0
  O  O18  1  0.205  0.094  0.898  1.0
  O  O19  1  0.337  0.360  0.741  1.0
  O  O20  1  0.340  0.859  0.759  1.0
  O  O21  1  0.408  0.607  0.082  1.0
  O  O22  1  0.705  0.907  0.898  1.0
  O  O23  1  0.806  0.402  0.398  1.0
  O  O24  1  0.163  0.359  0.259  1.0
  O  O25  1  0.296  0.092  0.102  1.0
  O  O26  1  0.194  0.599  0.601  1.0
  O  O27  1  0.592  0.391  0.918  1.0
  O  O28  1  0.306  0.597  0.398  1.0
  O  O29  1  0.837  0.641  0.741  1.0
  O  O30  1  0.840  0.142  0.759  1.0
  O  O31  1  0.591  0.887  0.582  1.0
  O  O32  1  0.908  0.392  0.082  1.0
  O  O33  1  0.661  0.142  0.241  1.0
  O  O34  1  0.663  0.640  0.259  1.0
  O  O35  1  0.694  0.403  0.602  1.0
[/CIF]
.