The crystal structure described by Tb8O13 crystallizes in the triclinic P1 space group. There are sixteen inequivalent Tb sites. In the first Tb site, Tb(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(5), one O(6), one O(7), and one O(9) atom. In the second Tb site, Tb(2) is bonded to one O(10), one O(2), one O(20), one O(26), one O(7), and one O(8) atom to form distorted TbO6 pentagonal pyramids that share  a cornercorner with one Tb(5)O6 octahedra,  a cornercorner with one Tb(9)O6 octahedra,  a cornercorner with one Tb(8)O7 pentagonal bipyramid,  an edgeedge with one Tb(14)O6 octahedra,  an edgeedge with one Tb(16)O7 pentagonal bipyramid,  an edgeedge with one Tb(3)O7 pentagonal bipyramid, and  an edgeedge with one Tb(4)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 43-52°. In the third Tb site, Tb(3) is bonded to one O(10), one O(19), one O(20), one O(21), one O(22), one O(4), and one O(5) atom to form distorted TbO7 pentagonal bipyramids that share  a cornercorner with one Tb(15)O7 pentagonal bipyramid,  a cornercorner with one Tb(4)O7 pentagonal bipyramid,  an edgeedge with one Tb(10)O6 octahedra,  an edgeedge with one Tb(5)O6 octahedra,  an edgeedge with one Tb(16)O7 pentagonal bipyramid,  an edgeedge with one Tb(7)O7 pentagonal bipyramid,  an edgeedge with one Tb(11)O6 pentagonal pyramid, and  an edgeedge with one Tb(2)O6 pentagonal pyramid. In the fourth Tb site, Tb(4) is bonded to one O(11), one O(21), one O(23), one O(24), one O(25), one O(26), and one O(7) atom to form distorted TbO7 pentagonal bipyramids that share  a cornercorner with one Tb(15)O7 pentagonal bipyramid,  a cornercorner with one Tb(3)O7 pentagonal bipyramid,  an edgeedge with one Tb(10)O6 octahedra,  an edgeedge with one Tb(14)O6 octahedra,  an edgeedge with one Tb(9)O6 octahedra,  an edgeedge with one Tb(16)O7 pentagonal bipyramid,  an edgeedge with one Tb(7)O7 pentagonal bipyramid,  an edgeedge with one Tb(8)O7 pentagonal bipyramid,  an edgeedge with one Tb(11)O6 pentagonal pyramid, and  an edgeedge with one Tb(2)O6 pentagonal pyramid. In the fifth Tb site, Tb(5) is bonded to one O(10), one O(14), one O(15), one O(18), one O(5), and one O(9) atom to form distorted TbO6 octahedra that share  a cornercorner with one Tb(14)O6 octahedra,  a cornercorner with one Tb(9)O6 octahedra,  a cornercorner with one Tb(16)O7 pentagonal bipyramid,  a cornercorner with one Tb(7)O7 pentagonal bipyramid,  a cornercorner with one Tb(11)O6 pentagonal pyramid,  a cornercorner with one Tb(2)O6 pentagonal pyramid,  an edgeedge with one Tb(10)O6 octahedra,  an edgeedge with one Tb(15)O7 pentagonal bipyramid,  an edgeedge with one Tb(3)O7 pentagonal bipyramid, and  an edgeedge with one Tb(8)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 60-62°. In the sixth Tb site, Tb(6) is bonded in a 7-coordinate geometry to one O(10), one O(11), one O(14), one O(16), one O(21), one O(3), and one O(8) atom. In the seventh Tb site, Tb(7) is bonded to one O(12), one O(19), one O(21), one O(25), one O(3), one O(6), and one O(9) atom to form distorted TbO7 pentagonal bipyramids that share  a cornercorner with one Tb(14)O6 octahedra,  a cornercorner with one Tb(5)O6 octahedra,  a cornercorner with one Tb(16)O7 pentagonal bipyramid,  an edgeedge with one Tb(9)O6 octahedra,  an edgeedge with one Tb(3)O7 pentagonal bipyramid,  an edgeedge with one Tb(4)O7 pentagonal bipyramid,  an edgeedge with one Tb(8)O7 pentagonal bipyramid, and  an edgeedge with one Tb(11)O6 pentagonal pyramid. The corner-sharing octahedral tilt angles range from 48-62°. In the eighth Tb site, Tb(8) is bonded to one O(11), one O(12), one O(13), one O(14), one O(17), one O(7), and one O(9) atom to form distorted TbO7 pentagonal bipyramids that share  a cornercorner with one Tb(11)O6 pentagonal pyramid,  a cornercorner with one Tb(2)O6 pentagonal pyramid,  an edgeedge with one Tb(10)O6 octahedra,  an edgeedge with one Tb(5)O6 octahedra,  an edgeedge with one Tb(15)O7 pentagonal bipyramid,  an edgeedge with one Tb(16)O7 pentagonal bipyramid,  an edgeedge with one Tb(4)O7 pentagonal bipyramid, and  an edgeedge with one Tb(7)O7 pentagonal bipyramid. In the ninth Tb site, Tb(9) is bonded to one O(16), one O(18), one O(2), one O(24), one O(25), and one O(6) atom to form distorted TbO6 octahedra that share  a cornercorner with one Tb(10)O6 octahedra,  a cornercorner with one Tb(5)O6 octahedra,  a cornercorner with one Tb(11)O6 pentagonal pyramid,  a cornercorner with one Tb(2)O6 pentagonal pyramid,  an edgeedge with one Tb(15)O7 pentagonal bipyramid,  an edgeedge with one Tb(16)O7 pentagonal bipyramid,  an edgeedge with one Tb(4)O7 pentagonal bipyramid, and  an edgeedge with one Tb(7)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 60-66°. In the tenth Tb site, Tb(10) is bonded to one O(11), one O(13), one O(18), one O(23), one O(4), and one O(5) atom to form distorted TbO6 octahedra that share  a cornercorner with one Tb(14)O6 octahedra,  a cornercorner with one Tb(9)O6 octahedra,  an edgeedge with one Tb(5)O6 octahedra,  an edgeedge with one Tb(16)O7 pentagonal bipyramid,  an edgeedge with one Tb(3)O7 pentagonal bipyramid,  an edgeedge with one Tb(4)O7 pentagonal bipyramid,  an edgeedge with one Tb(8)O7 pentagonal bipyramid, and  an edgeedge with one Tb(11)O6 pentagonal pyramid. The corner-sharing octahedral tilt angles range from 57-66°. In the eleventh Tb site, Tb(11) is bonded to one O(12), one O(15), one O(22), one O(23), one O(25), and one O(4) atom to form distorted TbO6 pentagonal pyramids that share  a cornercorner with one Tb(5)O6 octahedra,  a cornercorner with one Tb(9)O6 octahedra,  a cornercorner with one Tb(8)O7 pentagonal bipyramid,  an edgeedge with one Tb(10)O6 octahedra,  an edgeedge with one Tb(14)O6 octahedra,  an edgeedge with one Tb(15)O7 pentagonal bipyramid,  an edgeedge with one Tb(3)O7 pentagonal bipyramid,  an edgeedge with one Tb(4)O7 pentagonal bipyramid, and  an edgeedge with one Tb(7)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 44-51°. In the twelfth Tb site, Tb(12) is bonded in a 6-coordinate geometry to one O(13), one O(16), one O(19), one O(22), one O(6), and one O(8) atom. In the thirteenth Tb site, Tb(13) is bonded in a 7-coordinate geometry to one O(1), one O(12), one O(17), one O(2), one O(20), one O(3), and one O(4) atom. In the fourteenth Tb site, Tb(14) is bonded to one O(1), one O(15), one O(23), one O(26), one O(3), and one O(8) atom to form distorted TbO6 octahedra that share  a cornercorner with one Tb(10)O6 octahedra,  a cornercorner with one Tb(5)O6 octahedra,  a cornercorner with one Tb(16)O7 pentagonal bipyramid,  a cornercorner with one Tb(7)O7 pentagonal bipyramid,  an edgeedge with one Tb(15)O7 pentagonal bipyramid,  an edgeedge with one Tb(4)O7 pentagonal bipyramid,  an edgeedge with one Tb(11)O6 pentagonal pyramid, and  an edgeedge with one Tb(2)O6 pentagonal pyramid. The corner-sharing octahedral tilt angles range from 57-62°. In the fifteenth Tb site, Tb(15) is bonded to one O(1), one O(14), one O(15), one O(16), one O(17), one O(22), and one O(24) atom to form distorted TbO7 pentagonal bipyramids that share  a cornercorner with one Tb(3)O7 pentagonal bipyramid,  a cornercorner with one Tb(4)O7 pentagonal bipyramid,  an edgeedge with one Tb(14)O6 octahedra,  an edgeedge with one Tb(5)O6 octahedra,  an edgeedge with one Tb(9)O6 octahedra,  an edgeedge with one Tb(16)O7 pentagonal bipyramid,  an edgeedge with one Tb(8)O7 pentagonal bipyramid, and  an edgeedge with one Tb(11)O6 pentagonal pyramid. In the sixteenth Tb site, Tb(16) is bonded to one O(13), one O(17), one O(18), one O(19), one O(20), one O(24), and one O(26) atom to form distorted TbO7 pentagonal bipyramids that share  a cornercorner with one Tb(14)O6 octahedra,  a cornercorner with one Tb(5)O6 octahedra,  a cornercorner with one Tb(7)O7 pentagonal bipyramid,  an edgeedge with one Tb(10)O6 octahedra,  an edgeedge with one Tb(9)O6 octahedra,  an edgeedge with one Tb(15)O7 pentagonal bipyramid,  an edgeedge with one Tb(3)O7 pentagonal bipyramid,  an edgeedge with one Tb(4)O7 pentagonal bipyramid,  an edgeedge with one Tb(8)O7 pentagonal bipyramid, and  an edgeedge with one Tb(2)O6 pentagonal pyramid. The corner-sharing octahedral tilt angles range from 47-65°. There are twenty-six inequivalent O sites. In the first O site, O(1) is bonded to one Tb(1), one Tb(13), one Tb(14), and one Tb(15) atom to form a mixture of distorted corner and edge-sharing OTb4 tetrahedra. In the second O site, O(2) is bonded to one Tb(1), one Tb(13), one Tb(2), and one Tb(9) atom to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the third O site, O(3) is bonded to one Tb(13), one Tb(14), one Tb(6), and one Tb(7) atom to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the fourth O site, O(4) is bonded to one Tb(10), one Tb(11), one Tb(13), and one Tb(3) atom to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the fifth O site, O(5) is bonded to one Tb(1), one Tb(10), one Tb(3), and one Tb(5) atom to form a mixture of corner and edge-sharing OTb4 trigonal pyramids. In the sixth O site, O(6) is bonded to one Tb(1), one Tb(12), one Tb(7), and one Tb(9) atom to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the seventh O site, O(7) is bonded to one Tb(1), one Tb(2), one Tb(4), and one Tb(8) atom to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the eighth O site, O(8) is bonded to one Tb(12), one Tb(14), one Tb(2), and one Tb(6) atom to form a mixture of distorted corner and edge-sharing OTb4 trigonal pyramids. In the ninth O site, O(9) is bonded to one Tb(1), one Tb(5), one Tb(7), and one Tb(8) atom to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the tenth O site, O(10) is bonded to one Tb(2), one Tb(3), one Tb(5), and one Tb(6) atom to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the eleventh O site, O(11) is bonded to one Tb(10), one Tb(4), one Tb(6), and one Tb(8) atom to form a mixture of distorted corner and edge-sharing OTb4 tetrahedra. In the twelfth O site, O(12) is bonded to one Tb(11), one Tb(13), one Tb(7), and one Tb(8) atom to form a mixture of distorted corner and edge-sharing OTb4 trigonal pyramids. In the thirteenth O site, O(13) is bonded to one Tb(10), one Tb(12), one Tb(16), and one Tb(8) atom to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the fourteenth O site, O(14) is bonded to one Tb(15), one Tb(5), one Tb(6), and one Tb(8) atom to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the fifteenth O site, O(15) is bonded to one Tb(11), one Tb(14), one Tb(15), and one Tb(5) atom to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the sixteenth O site, O(16) is bonded to one Tb(12), one Tb(15), one Tb(6), and one Tb(9) atom to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the seventeenth O site, O(17) is bonded to one Tb(13), one Tb(15), one Tb(16), and one Tb(8) atom to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the eighteenth O site, O(18) is bonded to one Tb(10), one Tb(16), one Tb(5), and one Tb(9) atom to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the nineteenth O site, O(19) is bonded to one Tb(12), one Tb(16), one Tb(3), and one Tb(7) atom to form a mixture of distorted corner and edge-sharing OTb4 tetrahedra. In the twentieth O site, O(20) is bonded to one Tb(13), one Tb(16), one Tb(2), and one Tb(3) atom to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the twenty-first O site, O(21) is bonded to one Tb(3), one Tb(4), one Tb(6), and one Tb(7) atom to form a mixture of distorted corner and edge-sharing OTb4 tetrahedra. In the twenty-second O site, O(22) is bonded to one Tb(11), one Tb(12), one Tb(15), and one Tb(3) atom to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the twenty-third O site, O(23) is bonded to one Tb(10), one Tb(11), one Tb(14), and one Tb(4) atom to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the twenty-fourth O site, O(24) is bonded to one Tb(15), one Tb(16), one Tb(4), and one Tb(9) atom to form a mixture of distorted corner and edge-sharing OTb4 tetrahedra. In the twenty-fifth O site, O(25) is bonded to one Tb(11), one Tb(4), one Tb(7), and one Tb(9) atom to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the twenty-sixth O site, O(26) is bonded to one Tb(14), one Tb(16), one Tb(2), and one Tb(4) atom to form a mixture of corner and edge-sharing OTb4 tetrahedra. is represented by the CIF card [CIF]
data_Tb8O13
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.370
_cell_length_b   9.396
_cell_length_c   9.441
_cell_angle_alpha   108.663
_cell_angle_beta   111.409
_cell_angle_gamma   108.084
_symmetry_Int_Tables_number   1
_cell_volume   641.369
_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
  Tb  Tb0  1  0.275  0.527  0.745  1.0
  Tb  Tb1  1  0.193  0.726  0.479  1.0
  Tb  Tb2  1  0.011  0.493  0.021  1.0
  Tb  Tb3  1  0.999  0.774  0.740  1.0
  Tb  Tb4  1  0.473  0.729  0.220  1.0
  Tb  Tb5  1  0.241  0.970  0.264  1.0
  Tb  Tb6  1  0.756  0.768  0.974  1.0
  Tb  Tb7  1  0.491  0.995  0.009  1.0
  Tb  Tb8  1  0.526  0.500  0.512  1.0
  Tb  Tb9  1  0.267  0.268  0.008  1.0
  Tb  Tb10  1  0.812  0.039  0.774  1.0
  Tb  Tb11  1  0.525  0.264  0.746  1.0
  Tb  Tb12  1  0.984  0.247  0.260  1.0
  Tb  Tb13  1  0.999  0.004  0.492  1.0
  Tb  Tb14  1  0.729  0.220  0.483  1.0
  Tb  Tb15  1  0.732  0.468  0.249  1.0
  O  O16  1  0.024  0.269  0.539  1.0
  O  O17  1  0.268  0.503  0.480  1.0
  O  O18  1  0.991  0.993  0.239  1.0
  O  O19  1  0.042  0.255  0.043  1.0
  O  O20  1  0.228  0.482  0.954  1.0
  O  O21  1  0.502  0.492  0.752  1.0
  O  O22  1  0.242  0.755  0.747  1.0
  O  O23  1  0.268  0.011  0.542  1.0
  O  O24  1  0.531  0.758  0.018  1.0
  O  O25  1  0.262  0.736  0.275  1.0
  O  O26  1  0.249  0.024  0.041  1.0
  O  O27  1  0.713  0.009  0.955  1.0
  O  O28  1  0.484  0.235  0.963  1.0
  O  O29  1  0.479  0.983  0.238  1.0
  O  O30  1  0.728  0.956  0.472  1.0
  O  O31  1  0.475  0.239  0.471  1.0
  O  O32  1  0.739  0.232  0.250  1.0
  O  O33  1  0.503  0.508  0.266  1.0
  O  O34  1  0.758  0.536  0.026  1.0
  O  O35  1  0.975  0.484  0.240  1.0
  O  O36  1  0.001  0.722  0.973  1.0
  O  O37  1  0.764  0.257  0.756  1.0
  O  O38  1  0.042  0.036  0.754  1.0
  O  O39  1  0.788  0.495  0.538  1.0
  O  O40  1  0.742  0.767  0.728  1.0
  O  O41  1  0.951  0.741  0.460  1.0
[/CIF]
.
The crystal structure described by Tb8O13 crystallizes in the triclinic P1 space group. There are sixteen inequivalent Tb sites. In the first Tb site, Tb(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(5), one O(6), one O(7), and one O(9) atom. In the second Tb site, Tb(2) is bonded to one O(10), one O(2), one O(20), one O(26), one O(7), and one O(8) atom to form distorted TbO6 pentagonal pyramids that share  a cornercorner with one Tb(5)O6 octahedra,  a cornercorner with one Tb(9)O6 octahedra,  a cornercorner with one Tb(8)O7 pentagonal bipyramid,  an edgeedge with one Tb(14)O6 octahedra,  an edgeedge with one Tb(16)O7 pentagonal bipyramid,  an edgeedge with one Tb(3)O7 pentagonal bipyramid, and  an edgeedge with one Tb(4)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 43-52°. In the third Tb site, Tb(3) is bonded to one O(10), one O(19), one O(20), one O(21), one O(22), one O(4), and one O(5) atom to form distorted TbO7 pentagonal bipyramids that share  a cornercorner with one Tb(15)O7 pentagonal bipyramid,  a cornercorner with one Tb(4)O7 pentagonal bipyramid,  an edgeedge with one Tb(10)O6 octahedra,  an edgeedge with one Tb(5)O6 octahedra,  an edgeedge with one Tb(16)O7 pentagonal bipyramid,  an edgeedge with one Tb(7)O7 pentagonal bipyramid,  an edgeedge with one Tb(11)O6 pentagonal pyramid, and  an edgeedge with one Tb(2)O6 pentagonal pyramid. In the fourth Tb site, Tb(4) is bonded to one O(11), one O(21), one O(23), one O(24), one O(25), one O(26), and one O(7) atom to form distorted TbO7 pentagonal bipyramids that share  a cornercorner with one Tb(15)O7 pentagonal bipyramid,  a cornercorner with one Tb(3)O7 pentagonal bipyramid,  an edgeedge with one Tb(10)O6 octahedra,  an edgeedge with one Tb(14)O6 octahedra,  an edgeedge with one Tb(9)O6 octahedra,  an edgeedge with one Tb(16)O7 pentagonal bipyramid,  an edgeedge with one Tb(7)O7 pentagonal bipyramid,  an edgeedge with one Tb(8)O7 pentagonal bipyramid,  an edgeedge with one Tb(11)O6 pentagonal pyramid, and  an edgeedge with one Tb(2)O6 pentagonal pyramid. In the fifth Tb site, Tb(5) is bonded to one O(10), one O(14), one O(15), one O(18), one O(5), and one O(9) atom to form distorted TbO6 octahedra that share  a cornercorner with one Tb(14)O6 octahedra,  a cornercorner with one Tb(9)O6 octahedra,  a cornercorner with one Tb(16)O7 pentagonal bipyramid,  a cornercorner with one Tb(7)O7 pentagonal bipyramid,  a cornercorner with one Tb(11)O6 pentagonal pyramid,  a cornercorner with one Tb(2)O6 pentagonal pyramid,  an edgeedge with one Tb(10)O6 octahedra,  an edgeedge with one Tb(15)O7 pentagonal bipyramid,  an edgeedge with one Tb(3)O7 pentagonal bipyramid, and  an edgeedge with one Tb(8)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 60-62°. In the sixth Tb site, Tb(6) is bonded in a 7-coordinate geometry to one O(10), one O(11), one O(14), one O(16), one O(21), one O(3), and one O(8) atom. In the seventh Tb site, Tb(7) is bonded to one O(12), one O(19), one O(21), one O(25), one O(3), one O(6), and one O(9) atom to form distorted TbO7 pentagonal bipyramids that share  a cornercorner with one Tb(14)O6 octahedra,  a cornercorner with one Tb(5)O6 octahedra,  a cornercorner with one Tb(16)O7 pentagonal bipyramid,  an edgeedge with one Tb(9)O6 octahedra,  an edgeedge with one Tb(3)O7 pentagonal bipyramid,  an edgeedge with one Tb(4)O7 pentagonal bipyramid,  an edgeedge with one Tb(8)O7 pentagonal bipyramid, and  an edgeedge with one Tb(11)O6 pentagonal pyramid. The corner-sharing octahedral tilt angles range from 48-62°. In the eighth Tb site, Tb(8) is bonded to one O(11), one O(12), one O(13), one O(14), one O(17), one O(7), and one O(9) atom to form distorted TbO7 pentagonal bipyramids that share  a cornercorner with one Tb(11)O6 pentagonal pyramid,  a cornercorner with one Tb(2)O6 pentagonal pyramid,  an edgeedge with one Tb(10)O6 octahedra,  an edgeedge with one Tb(5)O6 octahedra,  an edgeedge with one Tb(15)O7 pentagonal bipyramid,  an edgeedge with one Tb(16)O7 pentagonal bipyramid,  an edgeedge with one Tb(4)O7 pentagonal bipyramid, and  an edgeedge with one Tb(7)O7 pentagonal bipyramid. In the ninth Tb site, Tb(9) is bonded to one O(16), one O(18), one O(2), one O(24), one O(25), and one O(6) atom to form distorted TbO6 octahedra that share  a cornercorner with one Tb(10)O6 octahedra,  a cornercorner with one Tb(5)O6 octahedra,  a cornercorner with one Tb(11)O6 pentagonal pyramid,  a cornercorner with one Tb(2)O6 pentagonal pyramid,  an edgeedge with one Tb(15)O7 pentagonal bipyramid,  an edgeedge with one Tb(16)O7 pentagonal bipyramid,  an edgeedge with one Tb(4)O7 pentagonal bipyramid, and  an edgeedge with one Tb(7)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 60-66°. In the tenth Tb site, Tb(10) is bonded to one O(11), one O(13), one O(18), one O(23), one O(4), and one O(5) atom to form distorted TbO6 octahedra that share  a cornercorner with one Tb(14)O6 octahedra,  a cornercorner with one Tb(9)O6 octahedra,  an edgeedge with one Tb(5)O6 octahedra,  an edgeedge with one Tb(16)O7 pentagonal bipyramid,  an edgeedge with one Tb(3)O7 pentagonal bipyramid,  an edgeedge with one Tb(4)O7 pentagonal bipyramid,  an edgeedge with one Tb(8)O7 pentagonal bipyramid, and  an edgeedge with one Tb(11)O6 pentagonal pyramid. The corner-sharing octahedral tilt angles range from 57-66°. In the eleventh Tb site, Tb(11) is bonded to one O(12), one O(15), one O(22), one O(23), one O(25), and one O(4) atom to form distorted TbO6 pentagonal pyramids that share  a cornercorner with one Tb(5)O6 octahedra,  a cornercorner with one Tb(9)O6 octahedra,  a cornercorner with one Tb(8)O7 pentagonal bipyramid,  an edgeedge with one Tb(10)O6 octahedra,  an edgeedge with one Tb(14)O6 octahedra,  an edgeedge with one Tb(15)O7 pentagonal bipyramid,  an edgeedge with one Tb(3)O7 pentagonal bipyramid,  an edgeedge with one Tb(4)O7 pentagonal bipyramid, and  an edgeedge with one Tb(7)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 44-51°. In the twelfth Tb site, Tb(12) is bonded in a 6-coordinate geometry to one O(13), one O(16), one O(19), one O(22), one O(6), and one O(8) atom. In the thirteenth Tb site, Tb(13) is bonded in a 7-coordinate geometry to one O(1), one O(12), one O(17), one O(2), one O(20), one O(3), and one O(4) atom. In the fourteenth Tb site, Tb(14) is bonded to one O(1), one O(15), one O(23), one O(26), one O(3), and one O(8) atom to form distorted TbO6 octahedra that share  a cornercorner with one Tb(10)O6 octahedra,  a cornercorner with one Tb(5)O6 octahedra,  a cornercorner with one Tb(16)O7 pentagonal bipyramid,  a cornercorner with one Tb(7)O7 pentagonal bipyramid,  an edgeedge with one Tb(15)O7 pentagonal bipyramid,  an edgeedge with one Tb(4)O7 pentagonal bipyramid,  an edgeedge with one Tb(11)O6 pentagonal pyramid, and  an edgeedge with one Tb(2)O6 pentagonal pyramid. The corner-sharing octahedral tilt angles range from 57-62°. In the fifteenth Tb site, Tb(15) is bonded to one O(1), one O(14), one O(15), one O(16), one O(17), one O(22), and one O(24) atom to form distorted TbO7 pentagonal bipyramids that share  a cornercorner with one Tb(3)O7 pentagonal bipyramid,  a cornercorner with one Tb(4)O7 pentagonal bipyramid,  an edgeedge with one Tb(14)O6 octahedra,  an edgeedge with one Tb(5)O6 octahedra,  an edgeedge with one Tb(9)O6 octahedra,  an edgeedge with one Tb(16)O7 pentagonal bipyramid,  an edgeedge with one Tb(8)O7 pentagonal bipyramid, and  an edgeedge with one Tb(11)O6 pentagonal pyramid. In the sixteenth Tb site, Tb(16) is bonded to one O(13), one O(17), one O(18), one O(19), one O(20), one O(24), and one O(26) atom to form distorted TbO7 pentagonal bipyramids that share  a cornercorner with one Tb(14)O6 octahedra,  a cornercorner with one Tb(5)O6 octahedra,  a cornercorner with one Tb(7)O7 pentagonal bipyramid,  an edgeedge with one Tb(10)O6 octahedra,  an edgeedge with one Tb(9)O6 octahedra,  an edgeedge with one Tb(15)O7 pentagonal bipyramid,  an edgeedge with one Tb(3)O7 pentagonal bipyramid,  an edgeedge with one Tb(4)O7 pentagonal bipyramid,  an edgeedge with one Tb(8)O7 pentagonal bipyramid, and  an edgeedge with one Tb(2)O6 pentagonal pyramid. The corner-sharing octahedral tilt angles range from 47-65°. There are twenty-six inequivalent O sites. In the first O site, O(1) is bonded to one Tb(1), one Tb(13), one Tb(14), and one Tb(15) atom to form a mixture of distorted corner and edge-sharing OTb4 tetrahedra. In the second O site, O(2) is bonded to one Tb(1), one Tb(13), one Tb(2), and one Tb(9) atom to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the third O site, O(3) is bonded to one Tb(13), one Tb(14), one Tb(6), and one Tb(7) atom to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the fourth O site, O(4) is bonded to one Tb(10), one Tb(11), one Tb(13), and one Tb(3) atom to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the fifth O site, O(5) is bonded to one Tb(1), one Tb(10), one Tb(3), and one Tb(5) atom to form a mixture of corner and edge-sharing OTb4 trigonal pyramids. In the sixth O site, O(6) is bonded to one Tb(1), one Tb(12), one Tb(7), and one Tb(9) atom to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the seventh O site, O(7) is bonded to one Tb(1), one Tb(2), one Tb(4), and one Tb(8) atom to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the eighth O site, O(8) is bonded to one Tb(12), one Tb(14), one Tb(2), and one Tb(6) atom to form a mixture of distorted corner and edge-sharing OTb4 trigonal pyramids. In the ninth O site, O(9) is bonded to one Tb(1), one Tb(5), one Tb(7), and one Tb(8) atom to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the tenth O site, O(10) is bonded to one Tb(2), one Tb(3), one Tb(5), and one Tb(6) atom to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the eleventh O site, O(11) is bonded to one Tb(10), one Tb(4), one Tb(6), and one Tb(8) atom to form a mixture of distorted corner and edge-sharing OTb4 tetrahedra. In the twelfth O site, O(12) is bonded to one Tb(11), one Tb(13), one Tb(7), and one Tb(8) atom to form a mixture of distorted corner and edge-sharing OTb4 trigonal pyramids. In the thirteenth O site, O(13) is bonded to one Tb(10), one Tb(12), one Tb(16), and one Tb(8) atom to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the fourteenth O site, O(14) is bonded to one Tb(15), one Tb(5), one Tb(6), and one Tb(8) atom to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the fifteenth O site, O(15) is bonded to one Tb(11), one Tb(14), one Tb(15), and one Tb(5) atom to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the sixteenth O site, O(16) is bonded to one Tb(12), one Tb(15), one Tb(6), and one Tb(9) atom to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the seventeenth O site, O(17) is bonded to one Tb(13), one Tb(15), one Tb(16), and one Tb(8) atom to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the eighteenth O site, O(18) is bonded to one Tb(10), one Tb(16), one Tb(5), and one Tb(9) atom to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the nineteenth O site, O(19) is bonded to one Tb(12), one Tb(16), one Tb(3), and one Tb(7) atom to form a mixture of distorted corner and edge-sharing OTb4 tetrahedra. In the twentieth O site, O(20) is bonded to one Tb(13), one Tb(16), one Tb(2), and one Tb(3) atom to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the twenty-first O site, O(21) is bonded to one Tb(3), one Tb(4), one Tb(6), and one Tb(7) atom to form a mixture of distorted corner and edge-sharing OTb4 tetrahedra. In the twenty-second O site, O(22) is bonded to one Tb(11), one Tb(12), one Tb(15), and one Tb(3) atom to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the twenty-third O site, O(23) is bonded to one Tb(10), one Tb(11), one Tb(14), and one Tb(4) atom to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the twenty-fourth O site, O(24) is bonded to one Tb(15), one Tb(16), one Tb(4), and one Tb(9) atom to form a mixture of distorted corner and edge-sharing OTb4 tetrahedra. In the twenty-fifth O site, O(25) is bonded to one Tb(11), one Tb(4), one Tb(7), and one Tb(9) atom to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the twenty-sixth O site, O(26) is bonded to one Tb(14), one Tb(16), one Tb(2), and one Tb(4) atom to form a mixture of corner and edge-sharing OTb4 tetrahedra. is represented by the CIF card [CIF]
data_Tb8O13
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.370
_cell_length_b   9.396
_cell_length_c   9.441
_cell_angle_alpha   108.663
_cell_angle_beta   111.409
_cell_angle_gamma   108.084
_symmetry_Int_Tables_number   1
_cell_volume   641.369
_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
  Tb  Tb0  1  0.275  0.527  0.745  1.0
  Tb  Tb1  1  0.193  0.726  0.479  1.0
  Tb  Tb2  1  0.011  0.493  0.021  1.0
  Tb  Tb3  1  0.999  0.774  0.740  1.0
  Tb  Tb4  1  0.473  0.729  0.220  1.0
  Tb  Tb5  1  0.241  0.970  0.264  1.0
  Tb  Tb6  1  0.756  0.768  0.974  1.0
  Tb  Tb7  1  0.491  0.995  0.009  1.0
  Tb  Tb8  1  0.526  0.500  0.512  1.0
  Tb  Tb9  1  0.267  0.268  0.008  1.0
  Tb  Tb10  1  0.812  0.039  0.774  1.0
  Tb  Tb11  1  0.525  0.264  0.746  1.0
  Tb  Tb12  1  0.984  0.247  0.260  1.0
  Tb  Tb13  1  0.999  0.004  0.492  1.0
  Tb  Tb14  1  0.729  0.220  0.483  1.0
  Tb  Tb15  1  0.732  0.468  0.249  1.0
  O  O16  1  0.024  0.269  0.539  1.0
  O  O17  1  0.268  0.503  0.480  1.0
  O  O18  1  0.991  0.993  0.239  1.0
  O  O19  1  0.042  0.255  0.043  1.0
  O  O20  1  0.228  0.482  0.954  1.0
  O  O21  1  0.502  0.492  0.752  1.0
  O  O22  1  0.242  0.755  0.747  1.0
  O  O23  1  0.268  0.011  0.542  1.0
  O  O24  1  0.531  0.758  0.018  1.0
  O  O25  1  0.262  0.736  0.275  1.0
  O  O26  1  0.249  0.024  0.041  1.0
  O  O27  1  0.713  0.009  0.955  1.0
  O  O28  1  0.484  0.235  0.963  1.0
  O  O29  1  0.479  0.983  0.238  1.0
  O  O30  1  0.728  0.956  0.472  1.0
  O  O31  1  0.475  0.239  0.471  1.0
  O  O32  1  0.739  0.232  0.250  1.0
  O  O33  1  0.503  0.508  0.266  1.0
  O  O34  1  0.758  0.536  0.026  1.0
  O  O35  1  0.975  0.484  0.240  1.0
  O  O36  1  0.001  0.722  0.973  1.0
  O  O37  1  0.764  0.257  0.756  1.0
  O  O38  1  0.042  0.036  0.754  1.0
  O  O39  1  0.788  0.495  0.538  1.0
  O  O40  1  0.742  0.767  0.728  1.0
  O  O41  1  0.951  0.741  0.460  1.0
[/CIF]
.