The structure described by Ge9(Sb5Te12)2 crystallizes in the triclinic P1 space group. There are nine inequivalent Ge sites. In the first Ge site, Ge(1) is bonded in a 4-coordinate geometry to one Te(12), one Te(17), one Te(5), and one Te(6) atom. In the second Ge site, Ge(2) is bonded in a 3-coordinate geometry to one Te(11), one Te(18), one Te(6), and one Te(8) atom. In the third Ge site, Ge(3) is bonded to one Te(7), one Te(8), two equivalent Te(13), and two equivalent Te(19) atoms to form distorted GeTe6 octahedra that share corners with four equivalent Ge(3)Te6 octahedra, edges with two equivalent Sb(1)Te6 octahedra, edges with two equivalent Sb(6)Te6 octahedra, and edges with four equivalent Ge(7)Te5 square pyramids. The corner-sharing octahedral tilt angles range from 6-7°. In the fourth Ge site, Ge(4) is bonded to one Te(10), one Te(5), two equivalent Te(16), and two equivalent Te(22) atoms to form distorted GeTe6 octahedra that share corners with four equivalent Ge(4)Te6 octahedra, edges with two equivalent Sb(10)Te6 octahedra, edges with two equivalent Sb(3)Te6 octahedra, edges with two equivalent Sb(4)Te6 octahedra, and edges with two equivalent Sb(9)Te6 square pyramids. The corner-sharing octahedral tilt angles are 9°. In the fifth Ge site, Ge(5) is bonded in a 4-coordinate geometry to one Te(11), two equivalent Te(2), and two equivalent Te(6) atoms. In the sixth Ge site, Ge(6) is bonded in a 5-coordinate geometry to one Te(14), one Te(23), one Te(4), and two equivalent Te(20) atoms. In the seventh Ge site, Ge(7) is bonded to one Te(3), two equivalent Te(13), and two equivalent Te(19) atoms to form distorted GeTe5 square pyramids that share corners with two equivalent Sb(1)Te6 octahedra, corners with two equivalent Sb(6)Te6 octahedra, corners with four equivalent Ge(7)Te5 square pyramids, and edges with four equivalent Ge(3)Te6 octahedra. The corner-sharing octahedral tilt angles range from 82-84°. In the eighth Ge site, Ge(8) is bonded in a 5-coordinate geometry to one Te(15), one Te(24), one Te(4), and two equivalent Te(21) atoms. In the ninth Ge site, Ge(9) is bonded in a 6-coordinate geometry to one Te(1), one Te(24), two equivalent Te(16), and two equivalent Te(22) atoms. There are ten inequivalent Sb sites. In the first Sb site, Sb(1) is bonded to one Te(13), one Te(14), two equivalent Te(23), and two equivalent Te(7) atoms to form SbTe6 octahedra that share  a cornercorner with one Sb(2)Te6 octahedra, corners with four equivalent Sb(1)Te6 octahedra, corners with two equivalent Ge(7)Te5 square pyramids, edges with two equivalent Ge(3)Te6 octahedra, and edges with four equivalent Sb(6)Te6 octahedra. The corner-sharing octahedral tilt angles range from 6-11°. In the second Sb site, Sb(2) is bonded to one Te(14), one Te(15), two equivalent Te(4), and two equivalent Te(9) atoms to form a mixture of distorted corner and edge-sharing SbTe6 octahedra. The corner-sharing octahedral tilt angles range from 6-19°. In the third Sb site, Sb(3) is bonded to one Te(15), one Te(16), two equivalent Te(10), and two equivalent Te(24) atoms to form SbTe6 octahedra that share  a cornercorner with one Sb(2)Te6 octahedra,  a cornercorner with one Sb(4)Te6 octahedra, corners with four equivalent Sb(3)Te6 octahedra, edges with two equivalent Ge(4)Te6 octahedra, and edges with four equivalent Sb(9)Te6 square pyramids. The corner-sharing octahedral tilt angles range from 4-16°. In the fourth Sb site, Sb(4) is bonded to one Te(12), one Te(16), two equivalent Te(1), and two equivalent Te(5) atoms to form distorted SbTe6 octahedra that share  a cornercorner with one Sb(3)Te6 octahedra, corners with four equivalent Sb(4)Te6 octahedra, edges with two equivalent Ge(4)Te6 octahedra, and edges with four equivalent Sb(10)Te6 octahedra. The corner-sharing octahedral tilt angles range from 4-15°. In the fifth Sb site, Sb(5) is bonded to one Te(17), one Te(18), two equivalent Te(2), and two equivalent Te(6) atoms to form corner-sharing SbTe6 octahedra. The corner-sharing octahedral tilt angles range from 7-12°. In the sixth Sb site, Sb(6) is bonded to one Te(19), one Te(20), two equivalent Te(23), and two equivalent Te(7) atoms to form SbTe6 octahedra that share  a cornercorner with one Sb(8)Te6 octahedra, corners with four equivalent Sb(6)Te6 octahedra, corners with two equivalent Ge(7)Te5 square pyramids, edges with two equivalent Ge(3)Te6 octahedra, and edges with four equivalent Sb(1)Te6 octahedra. The corner-sharing octahedral tilt angles range from 6-10°. In the seventh Sb site, Sb(7) is bonded in a 6-coordinate geometry to one Te(18), one Te(19), two equivalent Te(3), and two equivalent Te(8) atoms. In the eighth Sb site, Sb(8) is bonded to one Te(20), one Te(21), two equivalent Te(4), and two equivalent Te(9) atoms to form a mixture of distorted corner and edge-sharing SbTe6 octahedra. The corner-sharing octahedral tilt angles range from 10-19°. In the ninth Sb site, Sb(9) is bonded to one Te(21), one Te(22), two equivalent Te(10), and two equivalent Te(24) atoms to form distorted SbTe6 square pyramids that share  a cornercorner with one Sb(10)Te6 octahedra,  a cornercorner with one Sb(8)Te6 octahedra, corners with four equivalent Sb(9)Te6 square pyramids, edges with two equivalent Ge(4)Te6 octahedra, and edges with four equivalent Sb(3)Te6 octahedra. The corner-sharing octahedral tilt angles range from 4-8°. In the tenth Sb site, Sb(10) is bonded to one Te(17), one Te(22), two equivalent Te(1), and two equivalent Te(5) atoms to form SbTe6 octahedra that share  a cornercorner with one Sb(5)Te6 octahedra, corners with four equivalent Sb(10)Te6 octahedra,  a cornercorner with one Sb(9)Te6 square pyramid, edges with two equivalent Ge(4)Te6 octahedra, and edges with four equivalent Sb(4)Te6 octahedra. The corner-sharing octahedral tilt angles range from 2-7°. There are twenty-four inequivalent Te sites. In the first Te site, Te(1) is bonded to one Ge(9), two equivalent Sb(10), and two equivalent Sb(4) atoms to form TeGeSb4 square pyramids that share  a cornercorner with one Te(24)Ge2Sb4 octahedra, corners with four equivalent Te(1)GeSb4 square pyramids, and edges with four equivalent Te(5)Ge2Sb4 octahedra. The corner-sharing octahedral tilt angles are 7°. In the second Te site, Te(2) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Ge(5) and two equivalent Sb(5) atoms. In the third Te site, Te(3) is bonded in a distorted T-shaped geometry to one Ge(7) and two equivalent Sb(7) atoms. In the fourth Te site, Te(4) is bonded to one Ge(6), one Ge(8), two equivalent Sb(2), and two equivalent Sb(8) atoms to form distorted TeGe2Sb4 octahedra that share  a cornercorner with one Te(24)Ge2Sb4 octahedra, corners with four equivalent Te(4)Ge2Sb4 octahedra, and  a cornercorner with one Te(23)GeSb4 square pyramid. The corner-sharing octahedral tilt angles range from 11-15°. In the fifth Te site, Te(5) is bonded to one Ge(1), one Ge(4), two equivalent Sb(10), and two equivalent Sb(4) atoms to form TeGe2Sb4 octahedra that share  a cornercorner with one Te(6)Ge4Sb2 octahedra, corners with four equivalent Te(5)Ge2Sb4 octahedra,  a cornercorner with one Te(10)GeSb4 square pyramid, and edges with four equivalent Te(1)GeSb4 square pyramids. The corner-sharing octahedral tilt angles range from 2-12°. In the sixth Te site, Te(6) is bonded to one Ge(1), one Ge(2), two equivalent Ge(5), and two equivalent Sb(5) atoms to form distorted TeGe4Sb2 octahedra that share  a cornercorner with one Te(5)Ge2Sb4 octahedra and corners with four equivalent Te(6)Ge4Sb2 octahedra. The corner-sharing octahedral tilt angles range from 11-12°. In the seventh Te site, Te(7) is bonded to one Ge(3), two equivalent Sb(1), and two equivalent Sb(6) atoms to form TeGeSb4 square pyramids that share corners with four equivalent Te(7)GeSb4 square pyramids, edges with two equivalent Te(13)Ge4Sb square pyramids, and edges with four equivalent Te(23)GeSb4 square pyramids. In the eighth Te site, Te(8) is bonded in a rectangular see-saw-like geometry to one Ge(2), one Ge(3), and two equivalent Sb(7) atoms. In the ninth Te site, Te(9) is bonded in a distorted square co-planar geometry to two equivalent Sb(2) and two equivalent Sb(8) atoms. In the tenth Te site, Te(10) is bonded to one Ge(4), two equivalent Sb(3), and two equivalent Sb(9) atoms to form TeGeSb4 square pyramids that share  a cornercorner with one Te(5)Ge2Sb4 octahedra, corners with four equivalent Te(10)GeSb4 square pyramids, and edges with four equivalent Te(24)Ge2Sb4 octahedra. The corner-sharing octahedral tilt angles are 9°. In the eleventh Te site, Te(11) is bonded in an L-shaped geometry to one Ge(2) and one Ge(5) atom. In the twelfth Te site, Te(12) is bonded in an L-shaped geometry to one Ge(1) and one Sb(4) atom. In the thirteenth Te site, Te(13) is bonded to two equivalent Ge(3), two equivalent Ge(7), and one Sb(1) atom to form TeGe4Sb square pyramids that share corners with two equivalent Te(23)GeSb4 square pyramids, corners with four equivalent Te(13)Ge4Sb square pyramids, and edges with two equivalent Te(7)GeSb4 square pyramids. In the fourteenth Te site, Te(14) is bonded in a distorted T-shaped geometry to one Ge(6), one Sb(1), and one Sb(2) atom. In the fifteenth Te site, Te(15) is bonded in a 3-coordinate geometry to one Ge(8), one Sb(2), and one Sb(3) atom. In the sixteenth Te site, Te(16) is bonded in a 6-coordinate geometry to two equivalent Ge(4), two equivalent Ge(9), one Sb(3), and one Sb(4) atom. In the seventeenth Te site, Te(17) is bonded in a T-shaped geometry to one Ge(1), one Sb(10), and one Sb(5) atom. In the eighteenth Te site, Te(18) is bonded in a distorted T-shaped geometry to one Ge(2), one Sb(5), and one Sb(7) atom. In the nineteenth Te site, Te(19) is bonded in a 6-coordinate geometry to two equivalent Ge(3), two equivalent Ge(7), one Sb(6), and one Sb(7) atom. In the twentieth Te site, Te(20) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Ge(6), one Sb(6), and one Sb(8) atom. In the twenty-first Te site, Te(21) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Ge(8), one Sb(8), and one Sb(9) atom. In the twenty-second Te site, Te(22) is bonded in a 6-coordinate geometry to two equivalent Ge(4), two equivalent Ge(9), one Sb(10), and one Sb(9) atom. In the twenty-third Te site, Te(23) is bonded to one Ge(6), two equivalent Sb(1), and two equivalent Sb(6) atoms to form TeGeSb4 square pyramids that share  a cornercorner with one Te(4)Ge2Sb4 octahedra, corners with two equivalent Te(13)Ge4Sb square pyramids, corners with four equivalent Te(23)GeSb4 square pyramids, and edges with four equivalent Te(7)GeSb4 square pyramids. The corner-sharing octahedral tilt angles are 10°. In the twenty-fourth Te site, Te(24) is bonded to one Ge(8), one Ge(9), two equivalent Sb(3), and two equivalent Sb(9) atoms to form TeGe2Sb4 octahedra that share  a cornercorner with one Te(4)Ge2Sb4 octahedra, corners with four equivalent Te(24)Ge2Sb4 octahedra,  a cornercorner with one Te(1)GeSb4 square pyramid, and edges with four equivalent Te(10)GeSb4 square pyramids. The corner-sharing octahedral tilt angles range from 10-13°. is represented by the CIF file [CIF]
data_Ge9(Sb5Te12)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.143
_cell_length_b   6.196
_cell_length_c   37.144
_cell_angle_alpha   91.061
_cell_angle_beta   90.534
_cell_angle_gamma   90.354
_symmetry_Int_Tables_number   1
_cell_volume   1413.541
_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
  Ge  Ge0  1  0.538  0.457  0.913  1.0
  Ge  Ge1  1  0.565  0.459  0.745  1.0
  Ge  Ge2  1  0.529  0.471  0.584  1.0
  Ge  Ge3  1  0.527  0.472  0.085  1.0
  Ge  Ge4  1  0.008  0.524  0.826  1.0
  Ge  Ge5  1  0.022  0.960  0.419  1.0
  Ge  Ge6  1  0.004  0.981  0.593  1.0
  Ge  Ge7  1  0.021  0.960  0.251  1.0
  Ge  Ge8  1  0.009  0.968  0.081  1.0
  Sb  Sb9  1  0.996  0.490  0.506  1.0
  Sb  Sb10  1  0.973  0.489  0.342  1.0
  Sb  Sb11  1  0.989  0.490  0.175  1.0
  Sb  Sb12  1  0.995  0.489  0.991  1.0
  Sb  Sb13  1  0.476  0.973  0.839  1.0
  Sb  Sb14  1  0.495  0.978  0.503  1.0
  Sb  Sb15  1  0.483  0.952  0.674  1.0
  Sb  Sb16  1  0.490  0.965  0.342  1.0
  Sb  Sb17  1  0.493  0.984  0.177  1.0
  Sb  Sb18  1  0.501  0.985  0.000  1.0
  Te  Te19  1  0.994  0.992  0.003  1.0
  Te  Te20  1  0.013  0.993  0.831  1.0
  Te  Te21  1  0.003  0.008  0.664  1.0
  Te  Te22  1  0.995  0.997  0.333  1.0
  Te  Te23  1  0.495  0.493  0.999  1.0
  Te  Te24  1  0.507  0.496  0.833  1.0
  Te  Te25  1  0.495  0.490  0.499  1.0
  Te  Te26  1  0.506  0.492  0.665  1.0
  Te  Te27  1  0.492  0.498  0.328  1.0
  Te  Te28  1  0.493  0.492  0.163  1.0
  Te  Te29  1  0.006  0.502  0.754  1.0
  Te  Te30  1  0.993  0.501  0.916  1.0
  Te  Te31  1  0.999  0.500  0.583  1.0
  Te  Te32  1  0.001  0.511  0.418  1.0
  Te  Te33  1  0.006  0.513  0.251  1.0
  Te  Te34  1  0.990  0.509  0.084  1.0
  Te  Te35  1  0.484  0.007  0.918  1.0
  Te  Te36  1  0.484  0.011  0.749  1.0
  Te  Te37  1  0.505  0.007  0.582  1.0
  Te  Te38  1  0.488  0.013  0.418  1.0
  Te  Te39  1  0.490  0.011  0.251  1.0
  Te  Te40  1  0.495  0.004  0.082  1.0
  Te  Te41  1  0.998  0.989  0.498  1.0
  Te  Te42  1  0.992  0.996  0.168  1.0
[/CIF]
.
The structure described by Ge9(Sb5Te12)2 crystallizes in the triclinic P1 space group. There are nine inequivalent Ge sites. In the first Ge site, Ge(1) is bonded in a 4-coordinate geometry to one Te(12), one Te(17), one Te(5), and one Te(6) atom. In the second Ge site, Ge(2) is bonded in a 3-coordinate geometry to one Te(11), one Te(18), one Te(6), and one Te(8) atom. In the third Ge site, Ge(3) is bonded to one Te(7), one Te(8), two equivalent Te(13), and two equivalent Te(19) atoms to form distorted GeTe6 octahedra that share corners with four equivalent Ge(3)Te6 octahedra, edges with two equivalent Sb(1)Te6 octahedra, edges with two equivalent Sb(6)Te6 octahedra, and edges with four equivalent Ge(7)Te5 square pyramids. The corner-sharing octahedral tilt angles range from 6-7°. In the fourth Ge site, Ge(4) is bonded to one Te(10), one Te(5), two equivalent Te(16), and two equivalent Te(22) atoms to form distorted GeTe6 octahedra that share corners with four equivalent Ge(4)Te6 octahedra, edges with two equivalent Sb(10)Te6 octahedra, edges with two equivalent Sb(3)Te6 octahedra, edges with two equivalent Sb(4)Te6 octahedra, and edges with two equivalent Sb(9)Te6 square pyramids. The corner-sharing octahedral tilt angles are 9°. In the fifth Ge site, Ge(5) is bonded in a 4-coordinate geometry to one Te(11), two equivalent Te(2), and two equivalent Te(6) atoms. In the sixth Ge site, Ge(6) is bonded in a 5-coordinate geometry to one Te(14), one Te(23), one Te(4), and two equivalent Te(20) atoms. In the seventh Ge site, Ge(7) is bonded to one Te(3), two equivalent Te(13), and two equivalent Te(19) atoms to form distorted GeTe5 square pyramids that share corners with two equivalent Sb(1)Te6 octahedra, corners with two equivalent Sb(6)Te6 octahedra, corners with four equivalent Ge(7)Te5 square pyramids, and edges with four equivalent Ge(3)Te6 octahedra. The corner-sharing octahedral tilt angles range from 82-84°. In the eighth Ge site, Ge(8) is bonded in a 5-coordinate geometry to one Te(15), one Te(24), one Te(4), and two equivalent Te(21) atoms. In the ninth Ge site, Ge(9) is bonded in a 6-coordinate geometry to one Te(1), one Te(24), two equivalent Te(16), and two equivalent Te(22) atoms. There are ten inequivalent Sb sites. In the first Sb site, Sb(1) is bonded to one Te(13), one Te(14), two equivalent Te(23), and two equivalent Te(7) atoms to form SbTe6 octahedra that share  a cornercorner with one Sb(2)Te6 octahedra, corners with four equivalent Sb(1)Te6 octahedra, corners with two equivalent Ge(7)Te5 square pyramids, edges with two equivalent Ge(3)Te6 octahedra, and edges with four equivalent Sb(6)Te6 octahedra. The corner-sharing octahedral tilt angles range from 6-11°. In the second Sb site, Sb(2) is bonded to one Te(14), one Te(15), two equivalent Te(4), and two equivalent Te(9) atoms to form a mixture of distorted corner and edge-sharing SbTe6 octahedra. The corner-sharing octahedral tilt angles range from 6-19°. In the third Sb site, Sb(3) is bonded to one Te(15), one Te(16), two equivalent Te(10), and two equivalent Te(24) atoms to form SbTe6 octahedra that share  a cornercorner with one Sb(2)Te6 octahedra,  a cornercorner with one Sb(4)Te6 octahedra, corners with four equivalent Sb(3)Te6 octahedra, edges with two equivalent Ge(4)Te6 octahedra, and edges with four equivalent Sb(9)Te6 square pyramids. The corner-sharing octahedral tilt angles range from 4-16°. In the fourth Sb site, Sb(4) is bonded to one Te(12), one Te(16), two equivalent Te(1), and two equivalent Te(5) atoms to form distorted SbTe6 octahedra that share  a cornercorner with one Sb(3)Te6 octahedra, corners with four equivalent Sb(4)Te6 octahedra, edges with two equivalent Ge(4)Te6 octahedra, and edges with four equivalent Sb(10)Te6 octahedra. The corner-sharing octahedral tilt angles range from 4-15°. In the fifth Sb site, Sb(5) is bonded to one Te(17), one Te(18), two equivalent Te(2), and two equivalent Te(6) atoms to form corner-sharing SbTe6 octahedra. The corner-sharing octahedral tilt angles range from 7-12°. In the sixth Sb site, Sb(6) is bonded to one Te(19), one Te(20), two equivalent Te(23), and two equivalent Te(7) atoms to form SbTe6 octahedra that share  a cornercorner with one Sb(8)Te6 octahedra, corners with four equivalent Sb(6)Te6 octahedra, corners with two equivalent Ge(7)Te5 square pyramids, edges with two equivalent Ge(3)Te6 octahedra, and edges with four equivalent Sb(1)Te6 octahedra. The corner-sharing octahedral tilt angles range from 6-10°. In the seventh Sb site, Sb(7) is bonded in a 6-coordinate geometry to one Te(18), one Te(19), two equivalent Te(3), and two equivalent Te(8) atoms. In the eighth Sb site, Sb(8) is bonded to one Te(20), one Te(21), two equivalent Te(4), and two equivalent Te(9) atoms to form a mixture of distorted corner and edge-sharing SbTe6 octahedra. The corner-sharing octahedral tilt angles range from 10-19°. In the ninth Sb site, Sb(9) is bonded to one Te(21), one Te(22), two equivalent Te(10), and two equivalent Te(24) atoms to form distorted SbTe6 square pyramids that share  a cornercorner with one Sb(10)Te6 octahedra,  a cornercorner with one Sb(8)Te6 octahedra, corners with four equivalent Sb(9)Te6 square pyramids, edges with two equivalent Ge(4)Te6 octahedra, and edges with four equivalent Sb(3)Te6 octahedra. The corner-sharing octahedral tilt angles range from 4-8°. In the tenth Sb site, Sb(10) is bonded to one Te(17), one Te(22), two equivalent Te(1), and two equivalent Te(5) atoms to form SbTe6 octahedra that share  a cornercorner with one Sb(5)Te6 octahedra, corners with four equivalent Sb(10)Te6 octahedra,  a cornercorner with one Sb(9)Te6 square pyramid, edges with two equivalent Ge(4)Te6 octahedra, and edges with four equivalent Sb(4)Te6 octahedra. The corner-sharing octahedral tilt angles range from 2-7°. There are twenty-four inequivalent Te sites. In the first Te site, Te(1) is bonded to one Ge(9), two equivalent Sb(10), and two equivalent Sb(4) atoms to form TeGeSb4 square pyramids that share  a cornercorner with one Te(24)Ge2Sb4 octahedra, corners with four equivalent Te(1)GeSb4 square pyramids, and edges with four equivalent Te(5)Ge2Sb4 octahedra. The corner-sharing octahedral tilt angles are 7°. In the second Te site, Te(2) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Ge(5) and two equivalent Sb(5) atoms. In the third Te site, Te(3) is bonded in a distorted T-shaped geometry to one Ge(7) and two equivalent Sb(7) atoms. In the fourth Te site, Te(4) is bonded to one Ge(6), one Ge(8), two equivalent Sb(2), and two equivalent Sb(8) atoms to form distorted TeGe2Sb4 octahedra that share  a cornercorner with one Te(24)Ge2Sb4 octahedra, corners with four equivalent Te(4)Ge2Sb4 octahedra, and  a cornercorner with one Te(23)GeSb4 square pyramid. The corner-sharing octahedral tilt angles range from 11-15°. In the fifth Te site, Te(5) is bonded to one Ge(1), one Ge(4), two equivalent Sb(10), and two equivalent Sb(4) atoms to form TeGe2Sb4 octahedra that share  a cornercorner with one Te(6)Ge4Sb2 octahedra, corners with four equivalent Te(5)Ge2Sb4 octahedra,  a cornercorner with one Te(10)GeSb4 square pyramid, and edges with four equivalent Te(1)GeSb4 square pyramids. The corner-sharing octahedral tilt angles range from 2-12°. In the sixth Te site, Te(6) is bonded to one Ge(1), one Ge(2), two equivalent Ge(5), and two equivalent Sb(5) atoms to form distorted TeGe4Sb2 octahedra that share  a cornercorner with one Te(5)Ge2Sb4 octahedra and corners with four equivalent Te(6)Ge4Sb2 octahedra. The corner-sharing octahedral tilt angles range from 11-12°. In the seventh Te site, Te(7) is bonded to one Ge(3), two equivalent Sb(1), and two equivalent Sb(6) atoms to form TeGeSb4 square pyramids that share corners with four equivalent Te(7)GeSb4 square pyramids, edges with two equivalent Te(13)Ge4Sb square pyramids, and edges with four equivalent Te(23)GeSb4 square pyramids. In the eighth Te site, Te(8) is bonded in a rectangular see-saw-like geometry to one Ge(2), one Ge(3), and two equivalent Sb(7) atoms. In the ninth Te site, Te(9) is bonded in a distorted square co-planar geometry to two equivalent Sb(2) and two equivalent Sb(8) atoms. In the tenth Te site, Te(10) is bonded to one Ge(4), two equivalent Sb(3), and two equivalent Sb(9) atoms to form TeGeSb4 square pyramids that share  a cornercorner with one Te(5)Ge2Sb4 octahedra, corners with four equivalent Te(10)GeSb4 square pyramids, and edges with four equivalent Te(24)Ge2Sb4 octahedra. The corner-sharing octahedral tilt angles are 9°. In the eleventh Te site, Te(11) is bonded in an L-shaped geometry to one Ge(2) and one Ge(5) atom. In the twelfth Te site, Te(12) is bonded in an L-shaped geometry to one Ge(1) and one Sb(4) atom. In the thirteenth Te site, Te(13) is bonded to two equivalent Ge(3), two equivalent Ge(7), and one Sb(1) atom to form TeGe4Sb square pyramids that share corners with two equivalent Te(23)GeSb4 square pyramids, corners with four equivalent Te(13)Ge4Sb square pyramids, and edges with two equivalent Te(7)GeSb4 square pyramids. In the fourteenth Te site, Te(14) is bonded in a distorted T-shaped geometry to one Ge(6), one Sb(1), and one Sb(2) atom. In the fifteenth Te site, Te(15) is bonded in a 3-coordinate geometry to one Ge(8), one Sb(2), and one Sb(3) atom. In the sixteenth Te site, Te(16) is bonded in a 6-coordinate geometry to two equivalent Ge(4), two equivalent Ge(9), one Sb(3), and one Sb(4) atom. In the seventeenth Te site, Te(17) is bonded in a T-shaped geometry to one Ge(1), one Sb(10), and one Sb(5) atom. In the eighteenth Te site, Te(18) is bonded in a distorted T-shaped geometry to one Ge(2), one Sb(5), and one Sb(7) atom. In the nineteenth Te site, Te(19) is bonded in a 6-coordinate geometry to two equivalent Ge(3), two equivalent Ge(7), one Sb(6), and one Sb(7) atom. In the twentieth Te site, Te(20) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Ge(6), one Sb(6), and one Sb(8) atom. In the twenty-first Te site, Te(21) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Ge(8), one Sb(8), and one Sb(9) atom. In the twenty-second Te site, Te(22) is bonded in a 6-coordinate geometry to two equivalent Ge(4), two equivalent Ge(9), one Sb(10), and one Sb(9) atom. In the twenty-third Te site, Te(23) is bonded to one Ge(6), two equivalent Sb(1), and two equivalent Sb(6) atoms to form TeGeSb4 square pyramids that share  a cornercorner with one Te(4)Ge2Sb4 octahedra, corners with two equivalent Te(13)Ge4Sb square pyramids, corners with four equivalent Te(23)GeSb4 square pyramids, and edges with four equivalent Te(7)GeSb4 square pyramids. The corner-sharing octahedral tilt angles are 10°. In the twenty-fourth Te site, Te(24) is bonded to one Ge(8), one Ge(9), two equivalent Sb(3), and two equivalent Sb(9) atoms to form TeGe2Sb4 octahedra that share  a cornercorner with one Te(4)Ge2Sb4 octahedra, corners with four equivalent Te(24)Ge2Sb4 octahedra,  a cornercorner with one Te(1)GeSb4 square pyramid, and edges with four equivalent Te(10)GeSb4 square pyramids. The corner-sharing octahedral tilt angles range from 10-13°. is represented by the CIF file [CIF]
data_Ge9(Sb5Te12)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.143
_cell_length_b   6.196
_cell_length_c   37.144
_cell_angle_alpha   91.061
_cell_angle_beta   90.534
_cell_angle_gamma   90.354
_symmetry_Int_Tables_number   1
_cell_volume   1413.541
_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
  Ge  Ge0  1  0.538  0.457  0.913  1.0
  Ge  Ge1  1  0.565  0.459  0.745  1.0
  Ge  Ge2  1  0.529  0.471  0.584  1.0
  Ge  Ge3  1  0.527  0.472  0.085  1.0
  Ge  Ge4  1  0.008  0.524  0.826  1.0
  Ge  Ge5  1  0.022  0.960  0.419  1.0
  Ge  Ge6  1  0.004  0.981  0.593  1.0
  Ge  Ge7  1  0.021  0.960  0.251  1.0
  Ge  Ge8  1  0.009  0.968  0.081  1.0
  Sb  Sb9  1  0.996  0.490  0.506  1.0
  Sb  Sb10  1  0.973  0.489  0.342  1.0
  Sb  Sb11  1  0.989  0.490  0.175  1.0
  Sb  Sb12  1  0.995  0.489  0.991  1.0
  Sb  Sb13  1  0.476  0.973  0.839  1.0
  Sb  Sb14  1  0.495  0.978  0.503  1.0
  Sb  Sb15  1  0.483  0.952  0.674  1.0
  Sb  Sb16  1  0.490  0.965  0.342  1.0
  Sb  Sb17  1  0.493  0.984  0.177  1.0
  Sb  Sb18  1  0.501  0.985  0.000  1.0
  Te  Te19  1  0.994  0.992  0.003  1.0
  Te  Te20  1  0.013  0.993  0.831  1.0
  Te  Te21  1  0.003  0.008  0.664  1.0
  Te  Te22  1  0.995  0.997  0.333  1.0
  Te  Te23  1  0.495  0.493  0.999  1.0
  Te  Te24  1  0.507  0.496  0.833  1.0
  Te  Te25  1  0.495  0.490  0.499  1.0
  Te  Te26  1  0.506  0.492  0.665  1.0
  Te  Te27  1  0.492  0.498  0.328  1.0
  Te  Te28  1  0.493  0.492  0.163  1.0
  Te  Te29  1  0.006  0.502  0.754  1.0
  Te  Te30  1  0.993  0.501  0.916  1.0
  Te  Te31  1  0.999  0.500  0.583  1.0
  Te  Te32  1  0.001  0.511  0.418  1.0
  Te  Te33  1  0.006  0.513  0.251  1.0
  Te  Te34  1  0.990  0.509  0.084  1.0
  Te  Te35  1  0.484  0.007  0.918  1.0
  Te  Te36  1  0.484  0.011  0.749  1.0
  Te  Te37  1  0.505  0.007  0.582  1.0
  Te  Te38  1  0.488  0.013  0.418  1.0
  Te  Te39  1  0.490  0.011  0.251  1.0
  Te  Te40  1  0.495  0.004  0.082  1.0
  Te  Te41  1  0.998  0.989  0.498  1.0
  Te  Te42  1  0.992  0.996  0.168  1.0
[/CIF]
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