The material structure described by Ta2O5 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(15), one O(3), one O(4), one O(5), one O(7), and one O(8) atom to form distorted TaO7 pentagonal bipyramids that share corners with two equivalent Ta(4)O6 octahedra,  a cornercorner with one Ta(2)O7 pentagonal bipyramid,  a cornercorner with one Ta(6)O7 pentagonal bipyramid,  an edgeedge with one Ta(2)O7 pentagonal bipyramid,  an edgeedge with one Ta(6)O7 pentagonal bipyramid, and  an edgeedge with one Ta(5)O6 pentagonal pyramid. The corner-sharing octahedral tilt angles range from 30-50°. In the second Ta site, Ta(2) is bonded to one O(1), one O(10), one O(11), one O(2), one O(4), one O(5), and one O(6) atom to form distorted TaO7 pentagonal bipyramids that share corners with two equivalent Ta(4)O6 octahedra,  a cornercorner with one Ta(1)O7 pentagonal bipyramid,  an edgeedge with one Ta(1)O7 pentagonal bipyramid, and edges with two equivalent Ta(6)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 36-39°. In the third Ta site, Ta(3) is bonded in a 6-coordinate geometry to one O(1), one O(10), one O(11), one O(12), one O(15), and one O(8) atom. In the fourth Ta site, Ta(4) is bonded to one O(12), one O(13), one O(2), one O(3), one O(6), and one O(7) atom to form distorted TaO6 octahedra that share corners with two equivalent Ta(1)O7 pentagonal bipyramids, corners with two equivalent Ta(2)O7 pentagonal bipyramids,  a cornercorner with one Ta(5)O6 pentagonal pyramid, and  an edgeedge with one Ta(5)O6 pentagonal pyramid. In the fifth Ta site, Ta(5) is bonded to one O(12), one O(13), one O(14), one O(3), one O(8), and one O(9) atom to form distorted TaO6 pentagonal pyramids that share  a cornercorner with one Ta(4)O6 octahedra, corners with two equivalent Ta(6)O7 pentagonal bipyramids,  an edgeedge with one Ta(4)O6 octahedra, and  an edgeedge with one Ta(1)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles are 39°. In the sixth Ta site, Ta(6) is bonded to one O(10), one O(11), one O(14), one O(15), one O(4), one O(5), and one O(9) atom to form TaO7 pentagonal bipyramids that share  a cornercorner with one Ta(1)O7 pentagonal bipyramid, corners with two equivalent Ta(5)O6 pentagonal pyramids,  an edgeedge with one Ta(1)O7 pentagonal bipyramid, and edges with two equivalent Ta(2)O7 pentagonal bipyramids. There are fifteen inequivalent O sites. In the first O site, O(1) is bonded in a trigonal non-coplanar geometry to one Ta(1), one Ta(2), and one Ta(3) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Ta(2) and one Ta(4) atom. In the third O site, O(3) is bonded in a trigonal non-coplanar geometry to one Ta(1), one Ta(4), and one Ta(5) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Ta(1), one Ta(2), and one Ta(6) atom. In the fifth O site, O(5) is bonded in a distorted trigonal non-coplanar geometry to one Ta(1), one Ta(2), and one Ta(6) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one Ta(2) and one Ta(4) atom. In the seventh O site, O(7) is bonded in a bent 150 degrees geometry to one Ta(1) and one Ta(4) atom. In the eighth O site, O(8) is bonded in a trigonal planar geometry to one Ta(1), one Ta(3), and one Ta(5) atom. In the ninth O site, O(9) is bonded in a linear geometry to one Ta(5) and one Ta(6) atom. In the tenth O site, O(10) is bonded in a distorted trigonal non-coplanar geometry to one Ta(2), one Ta(3), and one Ta(6) atom. In the eleventh O site, O(11) is bonded in a distorted trigonal non-coplanar geometry to one Ta(2), one Ta(3), and one Ta(6) atom. In the twelfth O site, O(12) is bonded in a distorted trigonal planar geometry to one Ta(3), one Ta(4), and one Ta(5) atom. In the thirteenth O site, O(13) is bonded in a bent 150 degrees geometry to one Ta(4) and one Ta(5) atom. In the fourteenth O site, O(14) is bonded in a bent 120 degrees geometry to one Ta(5) and one Ta(6) atom. In the fifteenth O site, O(15) is bonded in a trigonal non-coplanar geometry to one Ta(1), one Ta(3), and one Ta(6) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ta2O5
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.925
_cell_length_b   7.473
_cell_length_c   7.153
_cell_angle_alpha   59.687
_cell_angle_beta   62.774
_cell_angle_gamma   64.929
_symmetry_Int_Tables_number   1
_cell_volume   275.030
_cell_formula_units_Z   3
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  0.257  0.965  0.028  1.0
  Ta  Ta1  1  0.232  0.029  0.535  1.0
  Ta  Ta2  1  0.750  0.040  0.992  1.0
  Ta  Ta3  1  0.270  0.480  0.984  1.0
  Ta  Ta4  1  0.705  0.554  0.012  1.0
  Ta  Ta5  1  0.773  0.979  0.472  1.0
  O  O6  1  0.063  0.105  0.818  1.0
  O  O7  1  0.199  0.314  0.320  1.0
  O  O8  1  0.369  0.650  0.069  1.0
  O  O9  1  0.143  0.963  0.337  1.0
  O  O10  1  0.457  0.011  0.677  1.0
  O  O11  1  0.308  0.711  0.693  1.0
  O  O12  1  0.318  0.237  0.926  1.0
  O  O13  1  0.577  0.839  0.057  1.0
  O  O14  1  0.739  0.283  0.269  1.0
  O  O15  1  0.557  0.988  0.322  1.0
  O  O16  1  0.857  0.039  0.676  1.0
  O  O17  1  0.631  0.341  0.934  1.0
  O  O18  1  0.954  0.590  0.035  1.0
  O  O19  1  0.822  0.673  0.689  1.0
  O  O20  1  0.947  0.886  0.196  1.0
[/CIF]
.
The material structure described by Ta2O5 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(15), one O(3), one O(4), one O(5), one O(7), and one O(8) atom to form distorted TaO7 pentagonal bipyramids that share corners with two equivalent Ta(4)O6 octahedra,  a cornercorner with one Ta(2)O7 pentagonal bipyramid,  a cornercorner with one Ta(6)O7 pentagonal bipyramid,  an edgeedge with one Ta(2)O7 pentagonal bipyramid,  an edgeedge with one Ta(6)O7 pentagonal bipyramid, and  an edgeedge with one Ta(5)O6 pentagonal pyramid. The corner-sharing octahedral tilt angles range from 30-50°. In the second Ta site, Ta(2) is bonded to one O(1), one O(10), one O(11), one O(2), one O(4), one O(5), and one O(6) atom to form distorted TaO7 pentagonal bipyramids that share corners with two equivalent Ta(4)O6 octahedra,  a cornercorner with one Ta(1)O7 pentagonal bipyramid,  an edgeedge with one Ta(1)O7 pentagonal bipyramid, and edges with two equivalent Ta(6)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 36-39°. In the third Ta site, Ta(3) is bonded in a 6-coordinate geometry to one O(1), one O(10), one O(11), one O(12), one O(15), and one O(8) atom. In the fourth Ta site, Ta(4) is bonded to one O(12), one O(13), one O(2), one O(3), one O(6), and one O(7) atom to form distorted TaO6 octahedra that share corners with two equivalent Ta(1)O7 pentagonal bipyramids, corners with two equivalent Ta(2)O7 pentagonal bipyramids,  a cornercorner with one Ta(5)O6 pentagonal pyramid, and  an edgeedge with one Ta(5)O6 pentagonal pyramid. In the fifth Ta site, Ta(5) is bonded to one O(12), one O(13), one O(14), one O(3), one O(8), and one O(9) atom to form distorted TaO6 pentagonal pyramids that share  a cornercorner with one Ta(4)O6 octahedra, corners with two equivalent Ta(6)O7 pentagonal bipyramids,  an edgeedge with one Ta(4)O6 octahedra, and  an edgeedge with one Ta(1)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles are 39°. In the sixth Ta site, Ta(6) is bonded to one O(10), one O(11), one O(14), one O(15), one O(4), one O(5), and one O(9) atom to form TaO7 pentagonal bipyramids that share  a cornercorner with one Ta(1)O7 pentagonal bipyramid, corners with two equivalent Ta(5)O6 pentagonal pyramids,  an edgeedge with one Ta(1)O7 pentagonal bipyramid, and edges with two equivalent Ta(2)O7 pentagonal bipyramids. There are fifteen inequivalent O sites. In the first O site, O(1) is bonded in a trigonal non-coplanar geometry to one Ta(1), one Ta(2), and one Ta(3) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Ta(2) and one Ta(4) atom. In the third O site, O(3) is bonded in a trigonal non-coplanar geometry to one Ta(1), one Ta(4), and one Ta(5) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Ta(1), one Ta(2), and one Ta(6) atom. In the fifth O site, O(5) is bonded in a distorted trigonal non-coplanar geometry to one Ta(1), one Ta(2), and one Ta(6) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one Ta(2) and one Ta(4) atom. In the seventh O site, O(7) is bonded in a bent 150 degrees geometry to one Ta(1) and one Ta(4) atom. In the eighth O site, O(8) is bonded in a trigonal planar geometry to one Ta(1), one Ta(3), and one Ta(5) atom. In the ninth O site, O(9) is bonded in a linear geometry to one Ta(5) and one Ta(6) atom. In the tenth O site, O(10) is bonded in a distorted trigonal non-coplanar geometry to one Ta(2), one Ta(3), and one Ta(6) atom. In the eleventh O site, O(11) is bonded in a distorted trigonal non-coplanar geometry to one Ta(2), one Ta(3), and one Ta(6) atom. In the twelfth O site, O(12) is bonded in a distorted trigonal planar geometry to one Ta(3), one Ta(4), and one Ta(5) atom. In the thirteenth O site, O(13) is bonded in a bent 150 degrees geometry to one Ta(4) and one Ta(5) atom. In the fourteenth O site, O(14) is bonded in a bent 120 degrees geometry to one Ta(5) and one Ta(6) atom. In the fifteenth O site, O(15) is bonded in a trigonal non-coplanar geometry to one Ta(1), one Ta(3), and one Ta(6) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ta2O5
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.925
_cell_length_b   7.473
_cell_length_c   7.153
_cell_angle_alpha   59.687
_cell_angle_beta   62.774
_cell_angle_gamma   64.929
_symmetry_Int_Tables_number   1
_cell_volume   275.030
_cell_formula_units_Z   3
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  0.257  0.965  0.028  1.0
  Ta  Ta1  1  0.232  0.029  0.535  1.0
  Ta  Ta2  1  0.750  0.040  0.992  1.0
  Ta  Ta3  1  0.270  0.480  0.984  1.0
  Ta  Ta4  1  0.705  0.554  0.012  1.0
  Ta  Ta5  1  0.773  0.979  0.472  1.0
  O  O6  1  0.063  0.105  0.818  1.0
  O  O7  1  0.199  0.314  0.320  1.0
  O  O8  1  0.369  0.650  0.069  1.0
  O  O9  1  0.143  0.963  0.337  1.0
  O  O10  1  0.457  0.011  0.677  1.0
  O  O11  1  0.308  0.711  0.693  1.0
  O  O12  1  0.318  0.237  0.926  1.0
  O  O13  1  0.577  0.839  0.057  1.0
  O  O14  1  0.739  0.283  0.269  1.0
  O  O15  1  0.557  0.988  0.322  1.0
  O  O16  1  0.857  0.039  0.676  1.0
  O  O17  1  0.631  0.341  0.934  1.0
  O  O18  1  0.954  0.590  0.035  1.0
  O  O19  1  0.822  0.673  0.689  1.0
  O  O20  1  0.947  0.886  0.196  1.0
[/CIF]
.