The compound described by Ta6Al8O27F is Hydrophilite-derived structured and crystallizes in the triclinic P1 space group. There are six inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to one O(1), one O(17), one O(21), one O(25), one O(6), and one O(9) atom to form TaO6 octahedra that share  a cornercorner with one Al(4)O5F octahedra,  a cornercorner with one Al(6)O5F octahedra,  a cornercorner with one Al(8)O5F octahedra,  a cornercorner with one Al(1)O6 octahedra,  a cornercorner with one Al(2)O6 octahedra,  a cornercorner with one Al(3)O6 octahedra,  a cornercorner with one Al(5)O6 octahedra,  a cornercorner with one Al(7)O6 octahedra,  an edgeedge with one Ta(3)O6 octahedra, and  an edgeedge with one Ta(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-55°. In the second Ta site, Ta(2) is bonded to one O(10), one O(18), one O(2), one O(22), one O(26), and one O(5) atom to form TaO6 octahedra that share  a cornercorner with one Al(4)O5F octahedra,  a cornercorner with one Al(6)O5F octahedra,  a cornercorner with one Al(8)O5F octahedra,  a cornercorner with one Al(1)O6 octahedra,  a cornercorner with one Al(2)O6 octahedra,  a cornercorner with one Al(3)O6 octahedra,  a cornercorner with one Al(5)O6 octahedra,  a cornercorner with one Al(7)O6 octahedra,  an edgeedge with one Ta(4)O6 octahedra, and  an edgeedge with one Ta(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-54°. In the third Ta site, Ta(3) is bonded to one O(1), one O(11), one O(20), one O(21), one O(23), and one O(7) atom to form TaO6 octahedra that share  a cornercorner with one Al(4)O5F octahedra,  a cornercorner with one Al(6)O5F octahedra,  a cornercorner with one Al(8)O5F octahedra,  a cornercorner with one Al(1)O6 octahedra,  a cornercorner with one Al(2)O6 octahedra,  a cornercorner with one Al(3)O6 octahedra,  a cornercorner with one Al(5)O6 octahedra,  a cornercorner with one Al(7)O6 octahedra,  an edgeedge with one Ta(1)O6 octahedra, and  an edgeedge with one Ta(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-55°. In the fourth Ta site, Ta(4) is bonded to one O(12), one O(19), one O(2), one O(22), one O(24), and one O(8) atom to form TaO6 octahedra that share  a cornercorner with one Al(4)O5F octahedra,  a cornercorner with one Al(6)O5F octahedra,  a cornercorner with one Al(8)O5F octahedra,  a cornercorner with one Al(1)O6 octahedra,  a cornercorner with one Al(2)O6 octahedra,  a cornercorner with one Al(3)O6 octahedra,  a cornercorner with one Al(5)O6 octahedra,  a cornercorner with one Al(7)O6 octahedra,  an edgeedge with one Ta(2)O6 octahedra, and  an edgeedge with one Ta(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-55°. In the fifth Ta site, Ta(5) is bonded to one O(1), one O(13), one O(16), one O(23), one O(25), and one O(3) atom to form TaO6 octahedra that share  a cornercorner with one Al(4)O5F octahedra,  a cornercorner with one Al(6)O5F octahedra,  a cornercorner with one Al(8)O5F octahedra,  a cornercorner with one Al(1)O6 octahedra,  a cornercorner with one Al(2)O6 octahedra,  a cornercorner with one Al(3)O6 octahedra,  a cornercorner with one Al(5)O6 octahedra,  a cornercorner with one Al(7)O6 octahedra,  an edgeedge with one Ta(1)O6 octahedra, and  an edgeedge with one Ta(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-54°. In the sixth Ta site, Ta(6) is bonded to one O(14), one O(15), one O(2), one O(24), one O(26), and one O(4) atom to form TaO6 octahedra that share  a cornercorner with one Al(4)O5F octahedra,  a cornercorner with one Al(6)O5F octahedra,  a cornercorner with one Al(8)O5F octahedra,  a cornercorner with one Al(1)O6 octahedra,  a cornercorner with one Al(2)O6 octahedra,  a cornercorner with one Al(3)O6 octahedra,  a cornercorner with one Al(5)O6 octahedra,  a cornercorner with one Al(7)O6 octahedra,  an edgeedge with one Ta(2)O6 octahedra, and  an edgeedge with one Ta(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-55°. There are eight inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(10), one O(11), one O(14), one O(16), one O(17), and one O(19) atom to form AlO6 octahedra that share  a cornercorner with one Ta(1)O6 octahedra,  a cornercorner with one Ta(2)O6 octahedra,  a cornercorner with one Ta(3)O6 octahedra,  a cornercorner with one Ta(4)O6 octahedra,  a cornercorner with one Ta(5)O6 octahedra,  a cornercorner with one Ta(6)O6 octahedra,  an edgeedge with one Al(4)O5F octahedra,  an edgeedge with one Al(5)O6 octahedra, and  an edgeedge with one Al(7)O6 octahedra. The corner-sharing octahedral tilt angles range from 48-55°. In the second Al site, Al(2) is bonded to one O(12), one O(13), one O(15), one O(18), one O(20), and one O(9) atom to form AlO6 octahedra that share  a cornercorner with one Ta(1)O6 octahedra,  a cornercorner with one Ta(2)O6 octahedra,  a cornercorner with one Ta(3)O6 octahedra,  a cornercorner with one Ta(4)O6 octahedra,  a cornercorner with one Ta(5)O6 octahedra,  a cornercorner with one Ta(6)O6 octahedra,  an edgeedge with one Al(6)O5F octahedra,  an edgeedge with one Al(8)O5F octahedra, and  an edgeedge with one Al(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 48-55°. In the third Al site, Al(3) is bonded to one O(15), one O(22), one O(27), one O(3), one O(7), and one O(9) atom to form AlO6 octahedra that share  a cornercorner with one Ta(1)O6 octahedra,  a cornercorner with one Ta(2)O6 octahedra,  a cornercorner with one Ta(3)O6 octahedra,  a cornercorner with one Ta(4)O6 octahedra,  a cornercorner with one Ta(5)O6 octahedra,  a cornercorner with one Ta(6)O6 octahedra,  an edgeedge with one Al(2)O6 octahedra,  an edgeedge with one Al(5)O6 octahedra, and  an edgeedge with one Al(7)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-54°. In the fourth Al site, Al(4) is bonded to one O(10), one O(16), one O(21), one O(4), one O(8), and one F(1) atom to form AlO5F octahedra that share  a cornercorner with one Ta(1)O6 octahedra,  a cornercorner with one Ta(2)O6 octahedra,  a cornercorner with one Ta(3)O6 octahedra,  a cornercorner with one Ta(4)O6 octahedra,  a cornercorner with one Ta(5)O6 octahedra,  a cornercorner with one Ta(6)O6 octahedra,  an edgeedge with one Al(6)O5F octahedra,  an edgeedge with one Al(8)O5F octahedra, and  an edgeedge with one Al(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-55°. In the fifth Al site, Al(5) is bonded to one O(11), one O(17), one O(24), one O(27), one O(3), and one O(5) atom to form AlO6 octahedra that share  a cornercorner with one Ta(1)O6 octahedra,  a cornercorner with one Ta(2)O6 octahedra,  a cornercorner with one Ta(3)O6 octahedra,  a cornercorner with one Ta(4)O6 octahedra,  a cornercorner with one Ta(5)O6 octahedra,  a cornercorner with one Ta(6)O6 octahedra,  an edgeedge with one Al(1)O6 octahedra,  an edgeedge with one Al(3)O6 octahedra, and  an edgeedge with one Al(7)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-53°. In the sixth Al site, Al(6) is bonded to one O(12), one O(18), one O(23), one O(4), one O(6), and one F(1) atom to form AlO5F octahedra that share  a cornercorner with one Ta(1)O6 octahedra,  a cornercorner with one Ta(2)O6 octahedra,  a cornercorner with one Ta(3)O6 octahedra,  a cornercorner with one Ta(4)O6 octahedra,  a cornercorner with one Ta(5)O6 octahedra,  a cornercorner with one Ta(6)O6 octahedra,  an edgeedge with one Al(4)O5F octahedra,  an edgeedge with one Al(8)O5F octahedra, and  an edgeedge with one Al(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-55°. In the seventh Al site, Al(7) is bonded to one O(14), one O(19), one O(25), one O(27), one O(5), and one O(7) atom to form AlO6 octahedra that share  a cornercorner with one Ta(1)O6 octahedra,  a cornercorner with one Ta(2)O6 octahedra,  a cornercorner with one Ta(3)O6 octahedra,  a cornercorner with one Ta(4)O6 octahedra,  a cornercorner with one Ta(5)O6 octahedra,  a cornercorner with one Ta(6)O6 octahedra,  an edgeedge with one Al(1)O6 octahedra,  an edgeedge with one Al(3)O6 octahedra, and  an edgeedge with one Al(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-54°. In the eighth Al site, Al(8) is bonded to one O(13), one O(20), one O(26), one O(6), one O(8), and one F(1) atom to form AlO5F octahedra that share  a cornercorner with one Ta(1)O6 octahedra,  a cornercorner with one Ta(2)O6 octahedra,  a cornercorner with one Ta(3)O6 octahedra,  a cornercorner with one Ta(4)O6 octahedra,  a cornercorner with one Ta(5)O6 octahedra,  a cornercorner with one Ta(6)O6 octahedra,  an edgeedge with one Al(4)O5F octahedra,  an edgeedge with one Al(6)O5F octahedra, and  an edgeedge with one Al(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-55°. There are twenty-seven inequivalent O sites. In the first O site, O(1) is bonded in a trigonal non-coplanar geometry to one Ta(1), one Ta(3), and one Ta(5) atom. In the second O site, O(2) is bonded in a trigonal non-coplanar geometry to one Ta(2), one Ta(4), and one Ta(6) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Ta(5), one Al(3), and one Al(5) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Ta(6), one Al(4), and one Al(6) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Ta(2), one Al(5), and one Al(7) atom. In the sixth O site, O(6) is bonded in a trigonal planar geometry to one Ta(1), one Al(6), and one Al(8) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Ta(3), one Al(3), and one Al(7) atom. In the eighth O site, O(8) is bonded in a trigonal planar geometry to one Ta(4), one Al(4), and one Al(8) atom. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Ta(1), one Al(2), and one Al(3) atom. In the tenth O site, O(10) is bonded in a distorted trigonal planar geometry to one Ta(2), one Al(1), and one Al(4) atom. In the eleventh O site, O(11) is bonded in a distorted trigonal planar geometry to one Ta(3), one Al(1), and one Al(5) atom. In the twelfth O site, O(12) is bonded in a distorted trigonal planar geometry to one Ta(4), one Al(2), and one Al(6) atom. In the thirteenth O site, O(13) is bonded in a distorted trigonal planar geometry to one Ta(5), one Al(2), and one Al(8) atom. In the fourteenth O site, O(14) is bonded in a distorted trigonal planar geometry to one Ta(6), one Al(1), and one Al(7) atom. In the fifteenth O site, O(15) is bonded in a distorted trigonal planar geometry to one Ta(6), one Al(2), and one Al(3) atom. In the sixteenth O site, O(16) is bonded in a distorted T-shaped geometry to one Ta(5), one Al(1), and one Al(4) atom. In the seventeenth O site, O(17) is bonded in a distorted trigonal planar geometry to one Ta(1), one Al(1), and one Al(5) atom. In the eighteenth O site, O(18) is bonded in a distorted T-shaped geometry to one Ta(2), one Al(2), and one Al(6) atom. In the nineteenth O site, O(19) is bonded in a distorted trigonal planar geometry to one Ta(4), one Al(1), and one Al(7) atom. In the twentieth O site, O(20) is bonded in a distorted T-shaped geometry to one Ta(3), one Al(2), and one Al(8) atom. In the twenty-first O site, O(21) is bonded in a trigonal planar geometry to one Ta(1), one Ta(3), and one Al(4) atom. In the twenty-second O site, O(22) is bonded in a trigonal planar geometry to one Ta(2), one Ta(4), and one Al(3) atom. In the twenty-third O site, O(23) is bonded in a trigonal planar geometry to one Ta(3), one Ta(5), and one Al(6) atom. In the twenty-fourth O site, O(24) is bonded in a trigonal planar geometry to one Ta(4), one Ta(6), and one Al(5) atom. In the twenty-fifth O site, O(25) is bonded in a trigonal planar geometry to one Ta(1), one Ta(5), and one Al(7) atom. In the twenty-sixth O site, O(26) is bonded in a trigonal planar geometry to one Ta(2), one Ta(6), and one Al(8) atom. In the twenty-seventh O site, O(27) is bonded in a trigonal non-coplanar geometry to one Al(3), one Al(5), and one Al(7) atom. F(1) is bonded in a distorted trigonal non-coplanar geometry to one Al(4), one Al(6), and one Al(8) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ta6Al8O27F
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.436
_cell_length_b   8.741
_cell_length_c   8.738
_cell_angle_alpha   63.371
_cell_angle_beta   115.161
_cell_angle_gamma   115.173
_symmetry_Int_Tables_number   1
_cell_volume   439.788
_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
  Ta  Ta0  1  0.282  0.072  0.819  1.0
  Ta  Ta1  1  0.283  0.570  0.322  1.0
  Ta  Ta2  1  0.111  0.820  0.570  1.0
  Ta  Ta3  1  0.108  0.321  0.072  1.0
  Ta  Ta4  1  0.609  0.982  0.735  1.0
  Ta  Ta5  1  0.608  0.485  0.233  1.0
  Al  Al6  1  0.001  0.872  0.129  1.0
  Al  Al7  1  1.000  0.372  0.627  1.0
  Al  Al8  1  0.876  0.161  0.412  1.0
  Al  Al9  1  0.882  0.659  0.922  1.0
  Al  Al10  1  0.426  0.027  0.276  1.0
  Al  Al11  1  0.419  0.518  0.783  1.0
  Al  Al12  1  0.696  0.936  0.187  1.0
  Al  Al13  1  0.700  0.428  0.691  1.0
  O  O14  1  0.333  0.050  0.616  1.0
  O  O15  1  0.333  0.552  0.115  1.0
  O  O16  1  0.622  0.022  0.504  1.0
  O  O17  1  0.627  0.527  0.999  1.0
  O  O18  1  0.474  0.807  0.289  1.0
  O  O19  1  0.474  0.314  0.787  1.0
  O  O20  1  0.904  0.948  0.430  1.0
  O  O21  1  0.899  0.450  0.923  1.0
  O  O22  1  0.048  0.169  0.641  1.0
  O  O23  1  0.049  0.667  0.147  1.0
  O  O24  1  0.190  0.882  0.355  1.0
  O  O25  1  0.185  0.378  0.857  1.0
  O  O26  1  0.765  0.236  0.715  1.0
  O  O27  1  0.763  0.739  0.213  1.0
  O  O28  1  0.822  0.371  0.393  1.0
  O  O29  1  0.823  0.867  0.893  1.0
  O  O30  1  0.236  0.018  0.041  1.0
  O  O31  1  0.239  0.519  0.544  1.0
  O  O32  1  0.940  0.076  0.100  1.0
  O  O33  1  0.938  0.576  0.601  1.0
  O  O34  1  0.082  0.818  0.796  1.0
  O  O35  1  0.085  0.320  0.295  1.0
  O  O36  1  0.387  0.744  0.724  1.0
  O  O37  1  0.384  0.248  0.221  1.0
  O  O38  1  0.529  0.970  0.945  1.0
  O  O39  1  0.533  0.470  0.448  1.0
  O  O40  1  0.667  0.130  0.204  1.0
  F  F41  1  0.667  0.639  0.694  1.0
[/CIF]
.
The compound described by Ta6Al8O27F is Hydrophilite-derived structured and crystallizes in the triclinic P1 space group. There are six inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to one O(1), one O(17), one O(21), one O(25), one O(6), and one O(9) atom to form TaO6 octahedra that share  a cornercorner with one Al(4)O5F octahedra,  a cornercorner with one Al(6)O5F octahedra,  a cornercorner with one Al(8)O5F octahedra,  a cornercorner with one Al(1)O6 octahedra,  a cornercorner with one Al(2)O6 octahedra,  a cornercorner with one Al(3)O6 octahedra,  a cornercorner with one Al(5)O6 octahedra,  a cornercorner with one Al(7)O6 octahedra,  an edgeedge with one Ta(3)O6 octahedra, and  an edgeedge with one Ta(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-55°. In the second Ta site, Ta(2) is bonded to one O(10), one O(18), one O(2), one O(22), one O(26), and one O(5) atom to form TaO6 octahedra that share  a cornercorner with one Al(4)O5F octahedra,  a cornercorner with one Al(6)O5F octahedra,  a cornercorner with one Al(8)O5F octahedra,  a cornercorner with one Al(1)O6 octahedra,  a cornercorner with one Al(2)O6 octahedra,  a cornercorner with one Al(3)O6 octahedra,  a cornercorner with one Al(5)O6 octahedra,  a cornercorner with one Al(7)O6 octahedra,  an edgeedge with one Ta(4)O6 octahedra, and  an edgeedge with one Ta(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-54°. In the third Ta site, Ta(3) is bonded to one O(1), one O(11), one O(20), one O(21), one O(23), and one O(7) atom to form TaO6 octahedra that share  a cornercorner with one Al(4)O5F octahedra,  a cornercorner with one Al(6)O5F octahedra,  a cornercorner with one Al(8)O5F octahedra,  a cornercorner with one Al(1)O6 octahedra,  a cornercorner with one Al(2)O6 octahedra,  a cornercorner with one Al(3)O6 octahedra,  a cornercorner with one Al(5)O6 octahedra,  a cornercorner with one Al(7)O6 octahedra,  an edgeedge with one Ta(1)O6 octahedra, and  an edgeedge with one Ta(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-55°. In the fourth Ta site, Ta(4) is bonded to one O(12), one O(19), one O(2), one O(22), one O(24), and one O(8) atom to form TaO6 octahedra that share  a cornercorner with one Al(4)O5F octahedra,  a cornercorner with one Al(6)O5F octahedra,  a cornercorner with one Al(8)O5F octahedra,  a cornercorner with one Al(1)O6 octahedra,  a cornercorner with one Al(2)O6 octahedra,  a cornercorner with one Al(3)O6 octahedra,  a cornercorner with one Al(5)O6 octahedra,  a cornercorner with one Al(7)O6 octahedra,  an edgeedge with one Ta(2)O6 octahedra, and  an edgeedge with one Ta(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-55°. In the fifth Ta site, Ta(5) is bonded to one O(1), one O(13), one O(16), one O(23), one O(25), and one O(3) atom to form TaO6 octahedra that share  a cornercorner with one Al(4)O5F octahedra,  a cornercorner with one Al(6)O5F octahedra,  a cornercorner with one Al(8)O5F octahedra,  a cornercorner with one Al(1)O6 octahedra,  a cornercorner with one Al(2)O6 octahedra,  a cornercorner with one Al(3)O6 octahedra,  a cornercorner with one Al(5)O6 octahedra,  a cornercorner with one Al(7)O6 octahedra,  an edgeedge with one Ta(1)O6 octahedra, and  an edgeedge with one Ta(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-54°. In the sixth Ta site, Ta(6) is bonded to one O(14), one O(15), one O(2), one O(24), one O(26), and one O(4) atom to form TaO6 octahedra that share  a cornercorner with one Al(4)O5F octahedra,  a cornercorner with one Al(6)O5F octahedra,  a cornercorner with one Al(8)O5F octahedra,  a cornercorner with one Al(1)O6 octahedra,  a cornercorner with one Al(2)O6 octahedra,  a cornercorner with one Al(3)O6 octahedra,  a cornercorner with one Al(5)O6 octahedra,  a cornercorner with one Al(7)O6 octahedra,  an edgeedge with one Ta(2)O6 octahedra, and  an edgeedge with one Ta(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-55°. There are eight inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(10), one O(11), one O(14), one O(16), one O(17), and one O(19) atom to form AlO6 octahedra that share  a cornercorner with one Ta(1)O6 octahedra,  a cornercorner with one Ta(2)O6 octahedra,  a cornercorner with one Ta(3)O6 octahedra,  a cornercorner with one Ta(4)O6 octahedra,  a cornercorner with one Ta(5)O6 octahedra,  a cornercorner with one Ta(6)O6 octahedra,  an edgeedge with one Al(4)O5F octahedra,  an edgeedge with one Al(5)O6 octahedra, and  an edgeedge with one Al(7)O6 octahedra. The corner-sharing octahedral tilt angles range from 48-55°. In the second Al site, Al(2) is bonded to one O(12), one O(13), one O(15), one O(18), one O(20), and one O(9) atom to form AlO6 octahedra that share  a cornercorner with one Ta(1)O6 octahedra,  a cornercorner with one Ta(2)O6 octahedra,  a cornercorner with one Ta(3)O6 octahedra,  a cornercorner with one Ta(4)O6 octahedra,  a cornercorner with one Ta(5)O6 octahedra,  a cornercorner with one Ta(6)O6 octahedra,  an edgeedge with one Al(6)O5F octahedra,  an edgeedge with one Al(8)O5F octahedra, and  an edgeedge with one Al(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 48-55°. In the third Al site, Al(3) is bonded to one O(15), one O(22), one O(27), one O(3), one O(7), and one O(9) atom to form AlO6 octahedra that share  a cornercorner with one Ta(1)O6 octahedra,  a cornercorner with one Ta(2)O6 octahedra,  a cornercorner with one Ta(3)O6 octahedra,  a cornercorner with one Ta(4)O6 octahedra,  a cornercorner with one Ta(5)O6 octahedra,  a cornercorner with one Ta(6)O6 octahedra,  an edgeedge with one Al(2)O6 octahedra,  an edgeedge with one Al(5)O6 octahedra, and  an edgeedge with one Al(7)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-54°. In the fourth Al site, Al(4) is bonded to one O(10), one O(16), one O(21), one O(4), one O(8), and one F(1) atom to form AlO5F octahedra that share  a cornercorner with one Ta(1)O6 octahedra,  a cornercorner with one Ta(2)O6 octahedra,  a cornercorner with one Ta(3)O6 octahedra,  a cornercorner with one Ta(4)O6 octahedra,  a cornercorner with one Ta(5)O6 octahedra,  a cornercorner with one Ta(6)O6 octahedra,  an edgeedge with one Al(6)O5F octahedra,  an edgeedge with one Al(8)O5F octahedra, and  an edgeedge with one Al(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-55°. In the fifth Al site, Al(5) is bonded to one O(11), one O(17), one O(24), one O(27), one O(3), and one O(5) atom to form AlO6 octahedra that share  a cornercorner with one Ta(1)O6 octahedra,  a cornercorner with one Ta(2)O6 octahedra,  a cornercorner with one Ta(3)O6 octahedra,  a cornercorner with one Ta(4)O6 octahedra,  a cornercorner with one Ta(5)O6 octahedra,  a cornercorner with one Ta(6)O6 octahedra,  an edgeedge with one Al(1)O6 octahedra,  an edgeedge with one Al(3)O6 octahedra, and  an edgeedge with one Al(7)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-53°. In the sixth Al site, Al(6) is bonded to one O(12), one O(18), one O(23), one O(4), one O(6), and one F(1) atom to form AlO5F octahedra that share  a cornercorner with one Ta(1)O6 octahedra,  a cornercorner with one Ta(2)O6 octahedra,  a cornercorner with one Ta(3)O6 octahedra,  a cornercorner with one Ta(4)O6 octahedra,  a cornercorner with one Ta(5)O6 octahedra,  a cornercorner with one Ta(6)O6 octahedra,  an edgeedge with one Al(4)O5F octahedra,  an edgeedge with one Al(8)O5F octahedra, and  an edgeedge with one Al(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-55°. In the seventh Al site, Al(7) is bonded to one O(14), one O(19), one O(25), one O(27), one O(5), and one O(7) atom to form AlO6 octahedra that share  a cornercorner with one Ta(1)O6 octahedra,  a cornercorner with one Ta(2)O6 octahedra,  a cornercorner with one Ta(3)O6 octahedra,  a cornercorner with one Ta(4)O6 octahedra,  a cornercorner with one Ta(5)O6 octahedra,  a cornercorner with one Ta(6)O6 octahedra,  an edgeedge with one Al(1)O6 octahedra,  an edgeedge with one Al(3)O6 octahedra, and  an edgeedge with one Al(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-54°. In the eighth Al site, Al(8) is bonded to one O(13), one O(20), one O(26), one O(6), one O(8), and one F(1) atom to form AlO5F octahedra that share  a cornercorner with one Ta(1)O6 octahedra,  a cornercorner with one Ta(2)O6 octahedra,  a cornercorner with one Ta(3)O6 octahedra,  a cornercorner with one Ta(4)O6 octahedra,  a cornercorner with one Ta(5)O6 octahedra,  a cornercorner with one Ta(6)O6 octahedra,  an edgeedge with one Al(4)O5F octahedra,  an edgeedge with one Al(6)O5F octahedra, and  an edgeedge with one Al(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-55°. There are twenty-seven inequivalent O sites. In the first O site, O(1) is bonded in a trigonal non-coplanar geometry to one Ta(1), one Ta(3), and one Ta(5) atom. In the second O site, O(2) is bonded in a trigonal non-coplanar geometry to one Ta(2), one Ta(4), and one Ta(6) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Ta(5), one Al(3), and one Al(5) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Ta(6), one Al(4), and one Al(6) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Ta(2), one Al(5), and one Al(7) atom. In the sixth O site, O(6) is bonded in a trigonal planar geometry to one Ta(1), one Al(6), and one Al(8) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Ta(3), one Al(3), and one Al(7) atom. In the eighth O site, O(8) is bonded in a trigonal planar geometry to one Ta(4), one Al(4), and one Al(8) atom. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Ta(1), one Al(2), and one Al(3) atom. In the tenth O site, O(10) is bonded in a distorted trigonal planar geometry to one Ta(2), one Al(1), and one Al(4) atom. In the eleventh O site, O(11) is bonded in a distorted trigonal planar geometry to one Ta(3), one Al(1), and one Al(5) atom. In the twelfth O site, O(12) is bonded in a distorted trigonal planar geometry to one Ta(4), one Al(2), and one Al(6) atom. In the thirteenth O site, O(13) is bonded in a distorted trigonal planar geometry to one Ta(5), one Al(2), and one Al(8) atom. In the fourteenth O site, O(14) is bonded in a distorted trigonal planar geometry to one Ta(6), one Al(1), and one Al(7) atom. In the fifteenth O site, O(15) is bonded in a distorted trigonal planar geometry to one Ta(6), one Al(2), and one Al(3) atom. In the sixteenth O site, O(16) is bonded in a distorted T-shaped geometry to one Ta(5), one Al(1), and one Al(4) atom. In the seventeenth O site, O(17) is bonded in a distorted trigonal planar geometry to one Ta(1), one Al(1), and one Al(5) atom. In the eighteenth O site, O(18) is bonded in a distorted T-shaped geometry to one Ta(2), one Al(2), and one Al(6) atom. In the nineteenth O site, O(19) is bonded in a distorted trigonal planar geometry to one Ta(4), one Al(1), and one Al(7) atom. In the twentieth O site, O(20) is bonded in a distorted T-shaped geometry to one Ta(3), one Al(2), and one Al(8) atom. In the twenty-first O site, O(21) is bonded in a trigonal planar geometry to one Ta(1), one Ta(3), and one Al(4) atom. In the twenty-second O site, O(22) is bonded in a trigonal planar geometry to one Ta(2), one Ta(4), and one Al(3) atom. In the twenty-third O site, O(23) is bonded in a trigonal planar geometry to one Ta(3), one Ta(5), and one Al(6) atom. In the twenty-fourth O site, O(24) is bonded in a trigonal planar geometry to one Ta(4), one Ta(6), and one Al(5) atom. In the twenty-fifth O site, O(25) is bonded in a trigonal planar geometry to one Ta(1), one Ta(5), and one Al(7) atom. In the twenty-sixth O site, O(26) is bonded in a trigonal planar geometry to one Ta(2), one Ta(6), and one Al(8) atom. In the twenty-seventh O site, O(27) is bonded in a trigonal non-coplanar geometry to one Al(3), one Al(5), and one Al(7) atom. F(1) is bonded in a distorted trigonal non-coplanar geometry to one Al(4), one Al(6), and one Al(8) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ta6Al8O27F
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.436
_cell_length_b   8.741
_cell_length_c   8.738
_cell_angle_alpha   63.371
_cell_angle_beta   115.161
_cell_angle_gamma   115.173
_symmetry_Int_Tables_number   1
_cell_volume   439.788
_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
  Ta  Ta0  1  0.282  0.072  0.819  1.0
  Ta  Ta1  1  0.283  0.570  0.322  1.0
  Ta  Ta2  1  0.111  0.820  0.570  1.0
  Ta  Ta3  1  0.108  0.321  0.072  1.0
  Ta  Ta4  1  0.609  0.982  0.735  1.0
  Ta  Ta5  1  0.608  0.485  0.233  1.0
  Al  Al6  1  0.001  0.872  0.129  1.0
  Al  Al7  1  1.000  0.372  0.627  1.0
  Al  Al8  1  0.876  0.161  0.412  1.0
  Al  Al9  1  0.882  0.659  0.922  1.0
  Al  Al10  1  0.426  0.027  0.276  1.0
  Al  Al11  1  0.419  0.518  0.783  1.0
  Al  Al12  1  0.696  0.936  0.187  1.0
  Al  Al13  1  0.700  0.428  0.691  1.0
  O  O14  1  0.333  0.050  0.616  1.0
  O  O15  1  0.333  0.552  0.115  1.0
  O  O16  1  0.622  0.022  0.504  1.0
  O  O17  1  0.627  0.527  0.999  1.0
  O  O18  1  0.474  0.807  0.289  1.0
  O  O19  1  0.474  0.314  0.787  1.0
  O  O20  1  0.904  0.948  0.430  1.0
  O  O21  1  0.899  0.450  0.923  1.0
  O  O22  1  0.048  0.169  0.641  1.0
  O  O23  1  0.049  0.667  0.147  1.0
  O  O24  1  0.190  0.882  0.355  1.0
  O  O25  1  0.185  0.378  0.857  1.0
  O  O26  1  0.765  0.236  0.715  1.0
  O  O27  1  0.763  0.739  0.213  1.0
  O  O28  1  0.822  0.371  0.393  1.0
  O  O29  1  0.823  0.867  0.893  1.0
  O  O30  1  0.236  0.018  0.041  1.0
  O  O31  1  0.239  0.519  0.544  1.0
  O  O32  1  0.940  0.076  0.100  1.0
  O  O33  1  0.938  0.576  0.601  1.0
  O  O34  1  0.082  0.818  0.796  1.0
  O  O35  1  0.085  0.320  0.295  1.0
  O  O36  1  0.387  0.744  0.724  1.0
  O  O37  1  0.384  0.248  0.221  1.0
  O  O38  1  0.529  0.970  0.945  1.0
  O  O39  1  0.533  0.470  0.448  1.0
  O  O40  1  0.667  0.130  0.204  1.0
  F  F41  1  0.667  0.639  0.694  1.0
[/CIF]
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