The compound described by Ag2Nb4O11 crystallizes in the monoclinic Cc space group. There are four inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 7-coordinate geometry to one O(1), one O(10), one O(11), one O(3), one O(7), one O(8), and one O(9) atom. In the second Nb site, Nb(2) is bonded in a 7-coordinate geometry to one O(10), one O(11), one O(2), one O(4), one O(7), one O(8), and one O(9) atom. In the third Nb site, Nb(3) is bonded to one O(10), one O(11), one O(5), one O(6), one O(7), one O(8), and one O(9) atom to form distorted corner-sharing NbO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 45-47°. In the fourth Nb site, Nb(4) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form corner-sharing NbO6 octahedra. There are two inequivalent Ag sites. In the first Ag site, Ag(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom. In the second Ag site, Ag(2) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom. There are eleven inequivalent O sites. In the first O site, O(5) is bonded in a 4-coordinate geometry to one Nb(3), one Nb(4), one Ag(1), and one Ag(2) atom. In the second O site, O(6) is bonded in a 4-coordinate geometry to one Nb(3), one Nb(4), one Ag(1), and one Ag(2) atom. In the third O site, O(7) is bonded in a distorted bent 150 degrees geometry to one Nb(1), one Nb(2), and one Nb(3) atom. In the fourth O site, O(8) is bonded in a 3-coordinate geometry to one Nb(1), one Nb(2), and one Nb(3) atom. In the fifth O site, O(9) is bonded in a trigonal non-coplanar geometry to one Nb(1), one Nb(2), and one Nb(3) atom. In the sixth O site, O(10) is bonded in a trigonal planar geometry to one Nb(1), one Nb(2), and one Nb(3) atom. In the seventh O site, O(11) is bonded in a 3-coordinate geometry to one Nb(1), one Nb(2), and one Nb(3) atom. In the eighth O site, O(1) is bonded in a 4-coordinate geometry to one Nb(1), one Nb(4), one Ag(1), and one Ag(2) atom. In the ninth O site, O(2) is bonded in a 4-coordinate geometry to one Nb(2), one Nb(4), one Ag(1), and one Ag(2) atom. In the tenth O site, O(3) is bonded in a 4-coordinate geometry to one Nb(1), one Nb(4), one Ag(1), and one Ag(2) atom. In the eleventh O site, O(4) is bonded in a 4-coordinate geometry to one Nb(2), one Nb(4), one Ag(1), and one Ag(2) atom. is represented by the CIF file [CIF]
data_Nb4Ag2O11
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.331
_cell_length_b   6.331
_cell_length_c   13.080
_cell_angle_alpha   76.159
_cell_angle_beta   76.159
_cell_angle_gamma   59.048
_symmetry_Int_Tables_number   1
_cell_volume   432.250
_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
  Nb  Nb0  1  0.754  0.608  0.249  1.0
  Nb  Nb1  1  0.608  0.754  0.749  1.0
  Nb  Nb2  1  0.394  0.245  0.249  1.0
  Nb  Nb3  1  0.245  0.394  0.749  1.0
  Nb  Nb4  1  0.126  0.882  0.242  1.0
  Nb  Nb5  1  0.882  0.126  0.742  1.0
  Nb  Nb6  1  0.516  0.000  0.993  1.0
  Nb  Nb7  1  0.000  0.516  0.493  1.0
  Ag  Ag8  1  0.323  0.835  0.511  1.0
  Ag  Ag9  1  0.835  0.323  0.011  1.0
  Ag  Ag10  1  0.178  0.664  0.986  1.0
  Ag  Ag11  1  0.664  0.178  0.486  1.0
  O  O12  1  0.743  0.719  0.096  1.0
  O  O13  1  0.719  0.743  0.596  1.0
  O  O14  1  0.274  0.254  0.409  1.0
  O  O15  1  0.254  0.274  0.909  1.0
  O  O16  1  0.750  0.570  0.409  1.0
  O  O17  1  0.570  0.750  0.909  1.0
  O  O18  1  0.436  0.239  0.096  1.0
  O  O19  1  0.239  0.436  0.596  1.0
  O  O20  1  0.221  0.938  0.093  1.0
  O  O21  1  0.938  0.221  0.593  1.0
  O  O22  1  0.059  0.778  0.409  1.0
  O  O23  1  0.778  0.059  0.909  1.0
  O  O24  1  0.993  0.248  0.254  1.0
  O  O25  1  0.248  0.993  0.754  1.0
  O  O26  1  0.753  0.004  0.250  1.0
  O  O27  1  0.004  0.753  0.750  1.0
  O  O28  1  0.407  0.905  0.281  1.0
  O  O29  1  0.905  0.407  0.781  1.0
  O  O30  1  0.094  0.591  0.220  1.0
  O  O31  1  0.591  0.094  0.720  1.0
  O  O32  1  0.494  0.504  0.252  1.0
  O  O33  1  0.504  0.494  0.752  1.0
[/CIF]
.
The compound described by Ag2Nb4O11 crystallizes in the monoclinic Cc space group. There are four inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 7-coordinate geometry to one O(1), one O(10), one O(11), one O(3), one O(7), one O(8), and one O(9) atom. In the second Nb site, Nb(2) is bonded in a 7-coordinate geometry to one O(10), one O(11), one O(2), one O(4), one O(7), one O(8), and one O(9) atom. In the third Nb site, Nb(3) is bonded to one O(10), one O(11), one O(5), one O(6), one O(7), one O(8), and one O(9) atom to form distorted corner-sharing NbO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 45-47°. In the fourth Nb site, Nb(4) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form corner-sharing NbO6 octahedra. There are two inequivalent Ag sites. In the first Ag site, Ag(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom. In the second Ag site, Ag(2) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom. There are eleven inequivalent O sites. In the first O site, O(5) is bonded in a 4-coordinate geometry to one Nb(3), one Nb(4), one Ag(1), and one Ag(2) atom. In the second O site, O(6) is bonded in a 4-coordinate geometry to one Nb(3), one Nb(4), one Ag(1), and one Ag(2) atom. In the third O site, O(7) is bonded in a distorted bent 150 degrees geometry to one Nb(1), one Nb(2), and one Nb(3) atom. In the fourth O site, O(8) is bonded in a 3-coordinate geometry to one Nb(1), one Nb(2), and one Nb(3) atom. In the fifth O site, O(9) is bonded in a trigonal non-coplanar geometry to one Nb(1), one Nb(2), and one Nb(3) atom. In the sixth O site, O(10) is bonded in a trigonal planar geometry to one Nb(1), one Nb(2), and one Nb(3) atom. In the seventh O site, O(11) is bonded in a 3-coordinate geometry to one Nb(1), one Nb(2), and one Nb(3) atom. In the eighth O site, O(1) is bonded in a 4-coordinate geometry to one Nb(1), one Nb(4), one Ag(1), and one Ag(2) atom. In the ninth O site, O(2) is bonded in a 4-coordinate geometry to one Nb(2), one Nb(4), one Ag(1), and one Ag(2) atom. In the tenth O site, O(3) is bonded in a 4-coordinate geometry to one Nb(1), one Nb(4), one Ag(1), and one Ag(2) atom. In the eleventh O site, O(4) is bonded in a 4-coordinate geometry to one Nb(2), one Nb(4), one Ag(1), and one Ag(2) atom. is represented by the CIF file [CIF]
data_Nb4Ag2O11
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.331
_cell_length_b   6.331
_cell_length_c   13.080
_cell_angle_alpha   76.159
_cell_angle_beta   76.159
_cell_angle_gamma   59.048
_symmetry_Int_Tables_number   1
_cell_volume   432.250
_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
  Nb  Nb0  1  0.754  0.608  0.249  1.0
  Nb  Nb1  1  0.608  0.754  0.749  1.0
  Nb  Nb2  1  0.394  0.245  0.249  1.0
  Nb  Nb3  1  0.245  0.394  0.749  1.0
  Nb  Nb4  1  0.126  0.882  0.242  1.0
  Nb  Nb5  1  0.882  0.126  0.742  1.0
  Nb  Nb6  1  0.516  0.000  0.993  1.0
  Nb  Nb7  1  0.000  0.516  0.493  1.0
  Ag  Ag8  1  0.323  0.835  0.511  1.0
  Ag  Ag9  1  0.835  0.323  0.011  1.0
  Ag  Ag10  1  0.178  0.664  0.986  1.0
  Ag  Ag11  1  0.664  0.178  0.486  1.0
  O  O12  1  0.743  0.719  0.096  1.0
  O  O13  1  0.719  0.743  0.596  1.0
  O  O14  1  0.274  0.254  0.409  1.0
  O  O15  1  0.254  0.274  0.909  1.0
  O  O16  1  0.750  0.570  0.409  1.0
  O  O17  1  0.570  0.750  0.909  1.0
  O  O18  1  0.436  0.239  0.096  1.0
  O  O19  1  0.239  0.436  0.596  1.0
  O  O20  1  0.221  0.938  0.093  1.0
  O  O21  1  0.938  0.221  0.593  1.0
  O  O22  1  0.059  0.778  0.409  1.0
  O  O23  1  0.778  0.059  0.909  1.0
  O  O24  1  0.993  0.248  0.254  1.0
  O  O25  1  0.248  0.993  0.754  1.0
  O  O26  1  0.753  0.004  0.250  1.0
  O  O27  1  0.004  0.753  0.750  1.0
  O  O28  1  0.407  0.905  0.281  1.0
  O  O29  1  0.905  0.407  0.781  1.0
  O  O30  1  0.094  0.591  0.220  1.0
  O  O31  1  0.591  0.094  0.720  1.0
  O  O32  1  0.494  0.504  0.252  1.0
  O  O33  1  0.504  0.494  0.752  1.0
[/CIF]
.