The compound described by B10Bi6O21 crystallizes in the triclinic P-1 space group. There are five inequivalent B sites. In the first B site, B(1) is bonded to one O(3), one O(4), one O(5), and one O(6) atom to form corner-sharing BO4 tetrahedra. In the second B site, B(2) is bonded in a trigonal planar geometry to one O(1), one O(4), and one O(9) atom. In the third B site, B(3) is bonded in a trigonal planar geometry to one O(11), one O(5), and one O(8) atom. In the fourth B site, B(4) is bonded to one O(10), one O(11), one O(6), and one O(9) atom to form corner-sharing BO4 tetrahedra. In the fifth B site, B(5) is bonded in a trigonal planar geometry to one O(10), one O(2), and one O(7) atom. There are three inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a distorted rectangular see-saw-like geometry to one O(1), one O(6), and two equivalent O(7) atoms. In the second Bi site, Bi(2) is bonded in a distorted bent 150 degrees geometry to one O(1) and one O(5) atom. In the third Bi site, Bi(3) is bonded in a water-like geometry to one O(3) and one O(8) atom. There are eleven inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one B(2), one Bi(1), and one Bi(2) atom. In the second O site, O(2) is bonded in a linear geometry to two equivalent B(5) atoms. In the third O site, O(3) is bonded in a distorted single-bond geometry to one B(1) and one Bi(3) atom. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one B(1) and one B(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one B(1), one B(3), and one Bi(2) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one B(1), one B(4), and one Bi(1) atom. In the seventh O site, O(7) is bonded in a distorted single-bond geometry to one B(5) and two equivalent Bi(1) atoms. In the eighth O site, O(8) is bonded in a distorted bent 120 degrees geometry to one B(3) and one Bi(3) atom. In the ninth O site, O(9) is bonded in a bent 120 degrees geometry to one B(2) and one B(4) atom. In the tenth O site, O(10) is bonded in a bent 120 degrees geometry to one B(4) and one B(5) atom. In the eleventh O site, O(11) is bonded in a bent 120 degrees geometry to one B(3) and one B(4) atom. is represented by the CIF file [CIF]
data_Bi6B10O21
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.089
_cell_length_b   7.162
_cell_length_c   11.353
_cell_angle_alpha   102.604
_cell_angle_beta   86.380
_cell_angle_gamma   116.692
_symmetry_Int_Tables_number   1
_cell_volume   502.158
_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
  Bi  Bi0  1  0.760  0.270  0.911  1.0
  Bi  Bi1  1  0.211  0.999  0.442  1.0
  Bi  Bi2  1  0.846  0.268  0.366  1.0
  Bi  Bi3  1  0.154  0.732  0.634  1.0
  Bi  Bi4  1  0.789  0.001  0.558  1.0
  Bi  Bi5  1  0.240  0.730  0.089  1.0
  B  B6  1  0.421  0.179  0.726  1.0
  B  B7  1  0.171  0.325  0.773  1.0
  B  B8  1  0.620  0.446  0.589  1.0
  B  B9  1  0.562  0.570  0.801  1.0
  B  B10  1  0.864  0.789  0.956  1.0
  B  B11  1  0.136  0.211  0.044  1.0
  B  B12  1  0.438  0.430  0.199  1.0
  B  B13  1  0.380  0.554  0.411  1.0
  B  B14  1  0.829  0.675  0.227  1.0
  B  B15  1  0.579  0.821  0.274  1.0
  O  O16  1  0.964  0.297  0.760  1.0
  O  O17  1  0.000  0.000  0.000  1.0
  O  O18  1  0.550  0.005  0.271  1.0
  O  O19  1  0.202  0.143  0.750  1.0
  O  O20  1  0.468  0.240  0.601  1.0
  O  O21  1  0.567  0.366  0.815  1.0
  O  O22  1  0.919  0.632  0.973  1.0
  O  O23  1  0.732  0.481  0.487  1.0
  O  O24  1  0.337  0.527  0.802  1.0
  O  O25  1  0.320  0.252  0.101  1.0
  O  O26  1  0.661  0.615  0.686  1.0
  O  O27  1  0.339  0.385  0.314  1.0
  O  O28  1  0.680  0.748  0.899  1.0
  O  O29  1  0.663  0.473  0.198  1.0
  O  O30  1  0.268  0.519  0.513  1.0
  O  O31  1  0.081  0.368  0.027  1.0
  O  O32  1  0.433  0.634  0.185  1.0
  O  O33  1  0.532  0.760  0.399  1.0
  O  O34  1  0.798  0.857  0.250  1.0
  O  O35  1  0.450  0.995  0.729  1.0
  O  O36  1  0.036  0.703  0.240  1.0
[/CIF]
.
The compound described by B10Bi6O21 crystallizes in the triclinic P-1 space group. There are five inequivalent B sites. In the first B site, B(1) is bonded to one O(3), one O(4), one O(5), and one O(6) atom to form corner-sharing BO4 tetrahedra. In the second B site, B(2) is bonded in a trigonal planar geometry to one O(1), one O(4), and one O(9) atom. In the third B site, B(3) is bonded in a trigonal planar geometry to one O(11), one O(5), and one O(8) atom. In the fourth B site, B(4) is bonded to one O(10), one O(11), one O(6), and one O(9) atom to form corner-sharing BO4 tetrahedra. In the fifth B site, B(5) is bonded in a trigonal planar geometry to one O(10), one O(2), and one O(7) atom. There are three inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a distorted rectangular see-saw-like geometry to one O(1), one O(6), and two equivalent O(7) atoms. In the second Bi site, Bi(2) is bonded in a distorted bent 150 degrees geometry to one O(1) and one O(5) atom. In the third Bi site, Bi(3) is bonded in a water-like geometry to one O(3) and one O(8) atom. There are eleven inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one B(2), one Bi(1), and one Bi(2) atom. In the second O site, O(2) is bonded in a linear geometry to two equivalent B(5) atoms. In the third O site, O(3) is bonded in a distorted single-bond geometry to one B(1) and one Bi(3) atom. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one B(1) and one B(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one B(1), one B(3), and one Bi(2) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one B(1), one B(4), and one Bi(1) atom. In the seventh O site, O(7) is bonded in a distorted single-bond geometry to one B(5) and two equivalent Bi(1) atoms. In the eighth O site, O(8) is bonded in a distorted bent 120 degrees geometry to one B(3) and one Bi(3) atom. In the ninth O site, O(9) is bonded in a bent 120 degrees geometry to one B(2) and one B(4) atom. In the tenth O site, O(10) is bonded in a bent 120 degrees geometry to one B(4) and one B(5) atom. In the eleventh O site, O(11) is bonded in a bent 120 degrees geometry to one B(3) and one B(4) atom. is represented by the CIF file [CIF]
data_Bi6B10O21
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.089
_cell_length_b   7.162
_cell_length_c   11.353
_cell_angle_alpha   102.604
_cell_angle_beta   86.380
_cell_angle_gamma   116.692
_symmetry_Int_Tables_number   1
_cell_volume   502.158
_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
  Bi  Bi0  1  0.760  0.270  0.911  1.0
  Bi  Bi1  1  0.211  0.999  0.442  1.0
  Bi  Bi2  1  0.846  0.268  0.366  1.0
  Bi  Bi3  1  0.154  0.732  0.634  1.0
  Bi  Bi4  1  0.789  0.001  0.558  1.0
  Bi  Bi5  1  0.240  0.730  0.089  1.0
  B  B6  1  0.421  0.179  0.726  1.0
  B  B7  1  0.171  0.325  0.773  1.0
  B  B8  1  0.620  0.446  0.589  1.0
  B  B9  1  0.562  0.570  0.801  1.0
  B  B10  1  0.864  0.789  0.956  1.0
  B  B11  1  0.136  0.211  0.044  1.0
  B  B12  1  0.438  0.430  0.199  1.0
  B  B13  1  0.380  0.554  0.411  1.0
  B  B14  1  0.829  0.675  0.227  1.0
  B  B15  1  0.579  0.821  0.274  1.0
  O  O16  1  0.964  0.297  0.760  1.0
  O  O17  1  0.000  0.000  0.000  1.0
  O  O18  1  0.550  0.005  0.271  1.0
  O  O19  1  0.202  0.143  0.750  1.0
  O  O20  1  0.468  0.240  0.601  1.0
  O  O21  1  0.567  0.366  0.815  1.0
  O  O22  1  0.919  0.632  0.973  1.0
  O  O23  1  0.732  0.481  0.487  1.0
  O  O24  1  0.337  0.527  0.802  1.0
  O  O25  1  0.320  0.252  0.101  1.0
  O  O26  1  0.661  0.615  0.686  1.0
  O  O27  1  0.339  0.385  0.314  1.0
  O  O28  1  0.680  0.748  0.899  1.0
  O  O29  1  0.663  0.473  0.198  1.0
  O  O30  1  0.268  0.519  0.513  1.0
  O  O31  1  0.081  0.368  0.027  1.0
  O  O32  1  0.433  0.634  0.185  1.0
  O  O33  1  0.532  0.760  0.399  1.0
  O  O34  1  0.798  0.857  0.250  1.0
  O  O35  1  0.450  0.995  0.729  1.0
  O  O36  1  0.036  0.703  0.240  1.0
[/CIF]
.