The structure described by Mo13Si2Sb2O28 crystallizes in the triclinic P1 space group. There are thirteen inequivalent Mo sites. In the first Mo site, Mo(1) is bonded in a 5-coordinate geometry to one O(21), one O(25), one O(27), one O(5), and one O(6) atom. In the second Mo site, Mo(2) is bonded to one O(1), one O(11), one O(14), one O(15), and one O(3) atom to form distorted MoO5 trigonal bipyramids that share  a cornercorner with one Mo(8)O6 octahedra,  a cornercorner with one Mo(9)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra,  a cornercorner with one Mo(10)O5 trigonal bipyramid, and  an edgeedge with one Mo(7)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 59-60°. In the third Mo site, Mo(3) is bonded in a 5-coordinate geometry to one O(22), one O(23), one O(24), one O(27), and one O(6) atom. In the fourth Mo site, Mo(4) is bonded in a 5-coordinate geometry to one O(1), one O(11), one O(12), one O(2), and one O(20) atom. In the fifth Mo site, Mo(5) is bonded to one O(16), one O(17), one O(22), one O(25), and one O(6) atom to form distorted MoO5 trigonal bipyramids that share  a cornercorner with one Mo(12)O6 octahedra,  a cornercorner with one Mo(8)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra,  a cornercorner with one Mo(7)O5 trigonal bipyramid, and  an edgeedge with one Mo(10)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 60°. In the sixth Mo site, Mo(6) is bonded to one O(13), one O(19), one O(20), one O(26), one O(7), and one O(8) atom to form distorted edge-sharing MoO6 octahedra. In the seventh Mo site, Mo(7) is bonded to one O(10), one O(11), one O(12), one O(15), and one O(16) atom to form distorted MoO5 trigonal bipyramids that share  a cornercorner with one Mo(8)O6 octahedra,  a cornercorner with one Mo(9)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra,  a cornercorner with one Mo(5)O5 trigonal bipyramid, and  an edgeedge with one Mo(2)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 59-60°. In the eighth Mo site, Mo(8) is bonded to one O(10), one O(14), one O(17), one O(18), one O(4), and one O(9) atom to form MoO6 octahedra that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Mo(10)O5 trigonal bipyramid,  a cornercorner with one Mo(2)O5 trigonal bipyramid,  a cornercorner with one Mo(5)O5 trigonal bipyramid,  a cornercorner with one Mo(7)O5 trigonal bipyramid, edges with two equivalent Mo(12)O6 octahedra, and edges with two equivalent Mo(9)O6 octahedra. In the ninth Mo site, Mo(9) is bonded to one O(10), one O(14), one O(20), one O(26), one O(4), and one O(9) atom to form MoO6 octahedra that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Mo(2)O5 trigonal bipyramid,  a cornercorner with one Mo(7)O5 trigonal bipyramid,  an edgeedge with one Mo(12)O6 octahedra,  an edgeedge with one Mo(6)O6 octahedra, and edges with two equivalent Mo(8)O6 octahedra. In the tenth Mo site, Mo(10) is bonded to one O(18), one O(22), one O(25), one O(27), and one O(3) atom to form distorted MoO5 trigonal bipyramids that share  a cornercorner with one Mo(12)O6 octahedra,  a cornercorner with one Mo(8)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra,  a cornercorner with one Mo(2)O5 trigonal bipyramid, and  an edgeedge with one Mo(5)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 60°. In the eleventh Mo site, Mo(11) is bonded in a 5-coordinate geometry to one O(1), one O(12), one O(15), one O(26), and one O(28) atom. In the twelfth Mo site, Mo(12) is bonded to one O(17), one O(18), one O(21), one O(23), one O(4), and one O(9) atom to form MoO6 octahedra that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Mo(10)O5 trigonal bipyramid,  a cornercorner with one Mo(5)O5 trigonal bipyramid,  an edgeedge with one Mo(13)O6 octahedra,  an edgeedge with one Mo(9)O6 octahedra, and edges with two equivalent Mo(8)O6 octahedra. In the thirteenth Mo site, Mo(13) is bonded to one O(13), one O(19), one O(21), one O(23), one O(7), and one O(8) atom to form distorted edge-sharing MoO6 octahedra. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(11), one O(22), one O(3), and one O(4) atom to form SiO4 tetrahedra that share  a cornercorner with one Mo(12)O6 octahedra,  a cornercorner with one Mo(8)O6 octahedra,  a cornercorner with one Mo(9)O6 octahedra,  a cornercorner with one Mo(5)O5 trigonal bipyramid,  a cornercorner with one Mo(7)O5 trigonal bipyramid, corners with two equivalent Mo(10)O5 trigonal bipyramids, and corners with two equivalent Mo(2)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 61-66°. In the second Si site, Si(2) is bonded to one O(15), one O(16), one O(25), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Mo(12)O6 octahedra,  a cornercorner with one Mo(8)O6 octahedra,  a cornercorner with one Mo(9)O6 octahedra,  a cornercorner with one Mo(10)O5 trigonal bipyramid,  a cornercorner with one Mo(2)O5 trigonal bipyramid, corners with two equivalent Mo(5)O5 trigonal bipyramids, and corners with two equivalent Mo(7)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 61-66°. There are two inequivalent Sb sites. In the first Sb site, Sb(1) is bonded in a 6-coordinate geometry to one O(10), one O(14), one O(19), one O(20), one O(26), and one O(8) atom. In the second Sb site, Sb(2) is bonded in a 6-coordinate geometry to one O(13), one O(17), one O(18), one O(21), one O(23), and one O(7) atom. There are twenty-eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one Mo(11), one Mo(2), and one Mo(4) atom. In the second O site, O(2) is bonded in a single-bond geometry to one Mo(4) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Mo(10), one Mo(2), and one Si(1) atom. In the fourth O site, O(4) is bonded to one Mo(12), one Mo(8), one Mo(9), and one Si(1) atom to form distorted OSiMo3 tetrahedra that share  a cornercorner with one O(20)SbMo3 tetrahedra,  a cornercorner with one O(9)SiMo3 tetrahedra, and  an edgeedge with one O(9)SiMo3 tetrahedra. In the fifth O site, O(5) is bonded in a single-bond geometry to one Mo(1) atom. In the sixth O site, O(6) is bonded in a distorted T-shaped geometry to one Mo(1), one Mo(3), and one Mo(5) atom. In the seventh O site, O(7) is bonded in a trigonal non-coplanar geometry to one Mo(13), one Mo(6), and one Sb(2) atom. In the eighth O site, O(8) is bonded in a trigonal non-coplanar geometry to one Mo(13), one Mo(6), and one Sb(1) atom. In the ninth O site, O(9) is bonded to one Mo(12), one Mo(8), one Mo(9), and one Si(2) atom to form distorted OSiMo3 tetrahedra that share  a cornercorner with one O(20)SbMo3 tetrahedra,  a cornercorner with one O(4)SiMo3 tetrahedra, and  an edgeedge with one O(4)SiMo3 tetrahedra. In the tenth O site, O(10) is bonded in a 4-coordinate geometry to one Mo(7), one Mo(8), one Mo(9), and one Sb(1) atom. In the eleventh O site, O(11) is bonded in a 4-coordinate geometry to one Mo(2), one Mo(4), one Mo(7), and one Si(1) atom. In the twelfth O site, O(12) is bonded in a distorted T-shaped geometry to one Mo(11), one Mo(4), and one Mo(7) atom. In the thirteenth O site, O(13) is bonded in a trigonal non-coplanar geometry to one Mo(13), one Mo(6), and one Sb(2) atom. In the fourteenth O site, O(14) is bonded in a 4-coordinate geometry to one Mo(2), one Mo(8), one Mo(9), and one Sb(1) atom. In the fifteenth O site, O(15) is bonded in a 4-coordinate geometry to one Mo(11), one Mo(2), one Mo(7), and one Si(2) atom. In the sixteenth O site, O(16) is bonded in a distorted trigonal planar geometry to one Mo(5), one Mo(7), and one Si(2) atom. In the seventeenth O site, O(17) is bonded in a 4-coordinate geometry to one Mo(12), one Mo(5), one Mo(8), and one Sb(2) atom. In the eighteenth O site, O(18) is bonded in a 4-coordinate geometry to one Mo(10), one Mo(12), one Mo(8), and one Sb(2) atom. In the nineteenth O site, O(19) is bonded in a trigonal non-coplanar geometry to one Mo(13), one Mo(6), and one Sb(1) atom. In the twentieth O site, O(20) is bonded to one Mo(4), one Mo(6), one Mo(9), and one Sb(1) atom to form distorted corner-sharing OSbMo3 tetrahedra. In the twenty-first O site, O(21) is bonded in a distorted rectangular see-saw-like geometry to one Mo(1), one Mo(12), one Mo(13), and one Sb(2) atom. In the twenty-second O site, O(22) is bonded in a 4-coordinate geometry to one Mo(10), one Mo(3), one Mo(5), and one Si(1) atom. In the twenty-third O site, O(23) is bonded in a distorted rectangular see-saw-like geometry to one Mo(12), one Mo(13), one Mo(3), and one Sb(2) atom. In the twenty-fourth O site, O(24) is bonded in a single-bond geometry to one Mo(3) atom. In the twenty-fifth O site, O(25) is bonded in a 4-coordinate geometry to one Mo(1), one Mo(10), one Mo(5), and one Si(2) atom. In the twenty-sixth O site, O(26) is bonded in a distorted rectangular see-saw-like geometry to one Mo(11), one Mo(6), one Mo(9), and one Sb(1) atom. In the twenty-seventh O site, O(27) is bonded in a distorted T-shaped geometry to one Mo(1), one Mo(10), and one Mo(3) atom. In the twenty-eighth O site, O(28) is bonded in a single-bond geometry to one Mo(11) atom. is represented by the CIF file [CIF]
data_Si2Sb2Mo13O28
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.978
_cell_length_b   8.948
_cell_length_c   12.633
_cell_angle_alpha   86.690
_cell_angle_beta   76.580
_cell_angle_gamma   75.890
_symmetry_Int_Tables_number   1
_cell_volume   637.475
_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
  Si  Si0  1  0.212  0.313  0.000  1.0
  Si  Si1  1  0.791  0.684  0.001  1.0
  Sb  Sb2  1  0.844  0.999  0.308  1.0
  Sb  Sb3  1  0.160  0.000  0.693  1.0
  Mo  Mo4  1  0.894  0.622  0.701  1.0
  Mo  Mo5  1  0.631  0.352  0.144  1.0
  Mo  Mo6  1  0.405  0.377  0.700  1.0
  Mo  Mo7  1  0.104  0.377  0.299  1.0
  Mo  Mo8  1  0.373  0.646  0.856  1.0
  Mo  Mo9  1  0.286  1.000  0.430  1.0
  Mo  Mo10  1  0.229  0.646  0.145  1.0
  Mo  Mo11  1  0.001  0.999  0.999  1.0
  Mo  Mo12  1  0.428  1.000  0.146  1.0
  Mo  Mo13  1  0.772  0.353  0.856  1.0
  Mo  Mo14  1  0.594  0.622  0.300  1.0
  Mo  Mo15  1  0.573  0.999  0.854  1.0
  Mo  Mo16  1  0.716  0.999  0.571  1.0
  O  O17  1  0.776  0.388  0.269  1.0
  O  O18  1  0.140  0.379  0.429  1.0
  O  O19  1  0.930  0.348  0.999  1.0
  O  O20  1  0.297  0.120  1.000  1.0
  O  O21  1  0.858  0.618  0.571  1.0
  O  O22  1  0.222  0.611  0.733  1.0
  O  O23  1  0.012  0.101  0.571  1.0
  O  O24  1  0.990  0.898  0.430  1.0
  O  O25  1  0.705  0.878  1.000  1.0
  O  O26  1  0.169  0.883  0.127  1.0
  O  O27  1  0.268  0.376  0.109  1.0
  O  O28  1  0.955  0.610  0.265  1.0
  O  O29  1  0.423  0.897  0.571  1.0
  O  O30  1  0.707  0.116  0.125  1.0
  O  O31  1  0.625  0.621  0.108  1.0
  O  O32  1  0.073  0.650  0.001  1.0
  O  O33  1  0.296  0.883  0.873  1.0
  O  O34  1  0.833  0.115  0.871  1.0
  O  O35  1  0.579  0.101  0.430  1.0
  O  O36  1  0.185  0.133  0.281  1.0
  O  O37  1  0.813  0.866  0.719  1.0
  O  O38  1  0.378  0.378  0.893  1.0
  O  O39  1  0.459  0.131  0.717  1.0
  O  O40  1  0.578  0.377  0.572  1.0
  O  O41  1  0.732  0.620  0.893  1.0
  O  O42  1  0.539  0.867  0.283  1.0
  O  O43  1  0.045  0.389  0.735  1.0
  O  O44  1  0.421  0.621  0.428  1.0
[/CIF]
.
The structure described by Mo13Si2Sb2O28 crystallizes in the triclinic P1 space group. There are thirteen inequivalent Mo sites. In the first Mo site, Mo(1) is bonded in a 5-coordinate geometry to one O(21), one O(25), one O(27), one O(5), and one O(6) atom. In the second Mo site, Mo(2) is bonded to one O(1), one O(11), one O(14), one O(15), and one O(3) atom to form distorted MoO5 trigonal bipyramids that share  a cornercorner with one Mo(8)O6 octahedra,  a cornercorner with one Mo(9)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra,  a cornercorner with one Mo(10)O5 trigonal bipyramid, and  an edgeedge with one Mo(7)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 59-60°. In the third Mo site, Mo(3) is bonded in a 5-coordinate geometry to one O(22), one O(23), one O(24), one O(27), and one O(6) atom. In the fourth Mo site, Mo(4) is bonded in a 5-coordinate geometry to one O(1), one O(11), one O(12), one O(2), and one O(20) atom. In the fifth Mo site, Mo(5) is bonded to one O(16), one O(17), one O(22), one O(25), and one O(6) atom to form distorted MoO5 trigonal bipyramids that share  a cornercorner with one Mo(12)O6 octahedra,  a cornercorner with one Mo(8)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra,  a cornercorner with one Mo(7)O5 trigonal bipyramid, and  an edgeedge with one Mo(10)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 60°. In the sixth Mo site, Mo(6) is bonded to one O(13), one O(19), one O(20), one O(26), one O(7), and one O(8) atom to form distorted edge-sharing MoO6 octahedra. In the seventh Mo site, Mo(7) is bonded to one O(10), one O(11), one O(12), one O(15), and one O(16) atom to form distorted MoO5 trigonal bipyramids that share  a cornercorner with one Mo(8)O6 octahedra,  a cornercorner with one Mo(9)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra,  a cornercorner with one Mo(5)O5 trigonal bipyramid, and  an edgeedge with one Mo(2)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 59-60°. In the eighth Mo site, Mo(8) is bonded to one O(10), one O(14), one O(17), one O(18), one O(4), and one O(9) atom to form MoO6 octahedra that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Mo(10)O5 trigonal bipyramid,  a cornercorner with one Mo(2)O5 trigonal bipyramid,  a cornercorner with one Mo(5)O5 trigonal bipyramid,  a cornercorner with one Mo(7)O5 trigonal bipyramid, edges with two equivalent Mo(12)O6 octahedra, and edges with two equivalent Mo(9)O6 octahedra. In the ninth Mo site, Mo(9) is bonded to one O(10), one O(14), one O(20), one O(26), one O(4), and one O(9) atom to form MoO6 octahedra that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Mo(2)O5 trigonal bipyramid,  a cornercorner with one Mo(7)O5 trigonal bipyramid,  an edgeedge with one Mo(12)O6 octahedra,  an edgeedge with one Mo(6)O6 octahedra, and edges with two equivalent Mo(8)O6 octahedra. In the tenth Mo site, Mo(10) is bonded to one O(18), one O(22), one O(25), one O(27), and one O(3) atom to form distorted MoO5 trigonal bipyramids that share  a cornercorner with one Mo(12)O6 octahedra,  a cornercorner with one Mo(8)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra,  a cornercorner with one Mo(2)O5 trigonal bipyramid, and  an edgeedge with one Mo(5)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 60°. In the eleventh Mo site, Mo(11) is bonded in a 5-coordinate geometry to one O(1), one O(12), one O(15), one O(26), and one O(28) atom. In the twelfth Mo site, Mo(12) is bonded to one O(17), one O(18), one O(21), one O(23), one O(4), and one O(9) atom to form MoO6 octahedra that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Mo(10)O5 trigonal bipyramid,  a cornercorner with one Mo(5)O5 trigonal bipyramid,  an edgeedge with one Mo(13)O6 octahedra,  an edgeedge with one Mo(9)O6 octahedra, and edges with two equivalent Mo(8)O6 octahedra. In the thirteenth Mo site, Mo(13) is bonded to one O(13), one O(19), one O(21), one O(23), one O(7), and one O(8) atom to form distorted edge-sharing MoO6 octahedra. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(11), one O(22), one O(3), and one O(4) atom to form SiO4 tetrahedra that share  a cornercorner with one Mo(12)O6 octahedra,  a cornercorner with one Mo(8)O6 octahedra,  a cornercorner with one Mo(9)O6 octahedra,  a cornercorner with one Mo(5)O5 trigonal bipyramid,  a cornercorner with one Mo(7)O5 trigonal bipyramid, corners with two equivalent Mo(10)O5 trigonal bipyramids, and corners with two equivalent Mo(2)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 61-66°. In the second Si site, Si(2) is bonded to one O(15), one O(16), one O(25), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Mo(12)O6 octahedra,  a cornercorner with one Mo(8)O6 octahedra,  a cornercorner with one Mo(9)O6 octahedra,  a cornercorner with one Mo(10)O5 trigonal bipyramid,  a cornercorner with one Mo(2)O5 trigonal bipyramid, corners with two equivalent Mo(5)O5 trigonal bipyramids, and corners with two equivalent Mo(7)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 61-66°. There are two inequivalent Sb sites. In the first Sb site, Sb(1) is bonded in a 6-coordinate geometry to one O(10), one O(14), one O(19), one O(20), one O(26), and one O(8) atom. In the second Sb site, Sb(2) is bonded in a 6-coordinate geometry to one O(13), one O(17), one O(18), one O(21), one O(23), and one O(7) atom. There are twenty-eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one Mo(11), one Mo(2), and one Mo(4) atom. In the second O site, O(2) is bonded in a single-bond geometry to one Mo(4) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Mo(10), one Mo(2), and one Si(1) atom. In the fourth O site, O(4) is bonded to one Mo(12), one Mo(8), one Mo(9), and one Si(1) atom to form distorted OSiMo3 tetrahedra that share  a cornercorner with one O(20)SbMo3 tetrahedra,  a cornercorner with one O(9)SiMo3 tetrahedra, and  an edgeedge with one O(9)SiMo3 tetrahedra. In the fifth O site, O(5) is bonded in a single-bond geometry to one Mo(1) atom. In the sixth O site, O(6) is bonded in a distorted T-shaped geometry to one Mo(1), one Mo(3), and one Mo(5) atom. In the seventh O site, O(7) is bonded in a trigonal non-coplanar geometry to one Mo(13), one Mo(6), and one Sb(2) atom. In the eighth O site, O(8) is bonded in a trigonal non-coplanar geometry to one Mo(13), one Mo(6), and one Sb(1) atom. In the ninth O site, O(9) is bonded to one Mo(12), one Mo(8), one Mo(9), and one Si(2) atom to form distorted OSiMo3 tetrahedra that share  a cornercorner with one O(20)SbMo3 tetrahedra,  a cornercorner with one O(4)SiMo3 tetrahedra, and  an edgeedge with one O(4)SiMo3 tetrahedra. In the tenth O site, O(10) is bonded in a 4-coordinate geometry to one Mo(7), one Mo(8), one Mo(9), and one Sb(1) atom. In the eleventh O site, O(11) is bonded in a 4-coordinate geometry to one Mo(2), one Mo(4), one Mo(7), and one Si(1) atom. In the twelfth O site, O(12) is bonded in a distorted T-shaped geometry to one Mo(11), one Mo(4), and one Mo(7) atom. In the thirteenth O site, O(13) is bonded in a trigonal non-coplanar geometry to one Mo(13), one Mo(6), and one Sb(2) atom. In the fourteenth O site, O(14) is bonded in a 4-coordinate geometry to one Mo(2), one Mo(8), one Mo(9), and one Sb(1) atom. In the fifteenth O site, O(15) is bonded in a 4-coordinate geometry to one Mo(11), one Mo(2), one Mo(7), and one Si(2) atom. In the sixteenth O site, O(16) is bonded in a distorted trigonal planar geometry to one Mo(5), one Mo(7), and one Si(2) atom. In the seventeenth O site, O(17) is bonded in a 4-coordinate geometry to one Mo(12), one Mo(5), one Mo(8), and one Sb(2) atom. In the eighteenth O site, O(18) is bonded in a 4-coordinate geometry to one Mo(10), one Mo(12), one Mo(8), and one Sb(2) atom. In the nineteenth O site, O(19) is bonded in a trigonal non-coplanar geometry to one Mo(13), one Mo(6), and one Sb(1) atom. In the twentieth O site, O(20) is bonded to one Mo(4), one Mo(6), one Mo(9), and one Sb(1) atom to form distorted corner-sharing OSbMo3 tetrahedra. In the twenty-first O site, O(21) is bonded in a distorted rectangular see-saw-like geometry to one Mo(1), one Mo(12), one Mo(13), and one Sb(2) atom. In the twenty-second O site, O(22) is bonded in a 4-coordinate geometry to one Mo(10), one Mo(3), one Mo(5), and one Si(1) atom. In the twenty-third O site, O(23) is bonded in a distorted rectangular see-saw-like geometry to one Mo(12), one Mo(13), one Mo(3), and one Sb(2) atom. In the twenty-fourth O site, O(24) is bonded in a single-bond geometry to one Mo(3) atom. In the twenty-fifth O site, O(25) is bonded in a 4-coordinate geometry to one Mo(1), one Mo(10), one Mo(5), and one Si(2) atom. In the twenty-sixth O site, O(26) is bonded in a distorted rectangular see-saw-like geometry to one Mo(11), one Mo(6), one Mo(9), and one Sb(1) atom. In the twenty-seventh O site, O(27) is bonded in a distorted T-shaped geometry to one Mo(1), one Mo(10), and one Mo(3) atom. In the twenty-eighth O site, O(28) is bonded in a single-bond geometry to one Mo(11) atom. is represented by the CIF file [CIF]
data_Si2Sb2Mo13O28
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.978
_cell_length_b   8.948
_cell_length_c   12.633
_cell_angle_alpha   86.690
_cell_angle_beta   76.580
_cell_angle_gamma   75.890
_symmetry_Int_Tables_number   1
_cell_volume   637.475
_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
  Si  Si0  1  0.212  0.313  0.000  1.0
  Si  Si1  1  0.791  0.684  0.001  1.0
  Sb  Sb2  1  0.844  0.999  0.308  1.0
  Sb  Sb3  1  0.160  0.000  0.693  1.0
  Mo  Mo4  1  0.894  0.622  0.701  1.0
  Mo  Mo5  1  0.631  0.352  0.144  1.0
  Mo  Mo6  1  0.405  0.377  0.700  1.0
  Mo  Mo7  1  0.104  0.377  0.299  1.0
  Mo  Mo8  1  0.373  0.646  0.856  1.0
  Mo  Mo9  1  0.286  1.000  0.430  1.0
  Mo  Mo10  1  0.229  0.646  0.145  1.0
  Mo  Mo11  1  0.001  0.999  0.999  1.0
  Mo  Mo12  1  0.428  1.000  0.146  1.0
  Mo  Mo13  1  0.772  0.353  0.856  1.0
  Mo  Mo14  1  0.594  0.622  0.300  1.0
  Mo  Mo15  1  0.573  0.999  0.854  1.0
  Mo  Mo16  1  0.716  0.999  0.571  1.0
  O  O17  1  0.776  0.388  0.269  1.0
  O  O18  1  0.140  0.379  0.429  1.0
  O  O19  1  0.930  0.348  0.999  1.0
  O  O20  1  0.297  0.120  1.000  1.0
  O  O21  1  0.858  0.618  0.571  1.0
  O  O22  1  0.222  0.611  0.733  1.0
  O  O23  1  0.012  0.101  0.571  1.0
  O  O24  1  0.990  0.898  0.430  1.0
  O  O25  1  0.705  0.878  1.000  1.0
  O  O26  1  0.169  0.883  0.127  1.0
  O  O27  1  0.268  0.376  0.109  1.0
  O  O28  1  0.955  0.610  0.265  1.0
  O  O29  1  0.423  0.897  0.571  1.0
  O  O30  1  0.707  0.116  0.125  1.0
  O  O31  1  0.625  0.621  0.108  1.0
  O  O32  1  0.073  0.650  0.001  1.0
  O  O33  1  0.296  0.883  0.873  1.0
  O  O34  1  0.833  0.115  0.871  1.0
  O  O35  1  0.579  0.101  0.430  1.0
  O  O36  1  0.185  0.133  0.281  1.0
  O  O37  1  0.813  0.866  0.719  1.0
  O  O38  1  0.378  0.378  0.893  1.0
  O  O39  1  0.459  0.131  0.717  1.0
  O  O40  1  0.578  0.377  0.572  1.0
  O  O41  1  0.732  0.620  0.893  1.0
  O  O42  1  0.539  0.867  0.283  1.0
  O  O43  1  0.045  0.389  0.735  1.0
  O  O44  1  0.421  0.621  0.428  1.0
[/CIF]
.