The material structure described by Mg4Sb2O9 is Ilmenite-like structured and crystallizes in the triclinic P-1 space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 6-coordinate geometry to one O(3), one O(7), two equivalent O(2), and two equivalent O(4) atoms. In the second Mg site, Mg(2) is bonded to one O(1), one O(2), one O(3), one O(5), one O(6), and one O(9) atom to form distorted MgO6 octahedra that share corners with two equivalent Mg(3)O6 octahedra, corners with four equivalent Mg(4)O6 octahedra,  an edgeedge with one Sb(1)O6 octahedra, edges with two equivalent Sb(2)O6 octahedra, and  a faceface with one Mg(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 44-64°. In the third Mg site, Mg(3) is bonded to one O(1), one O(5), one O(8), one O(9), and two equivalent O(6) atoms to form MgO6 octahedra that share  a cornercorner with one Sb(1)O6 octahedra, corners with two equivalent Mg(2)O6 octahedra, corners with six equivalent Sb(2)O6 octahedra,  an edgeedge with one Mg(3)O6 octahedra, edges with two equivalent Mg(4)O6 octahedra, and  a faceface with one Mg(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 43-64°. In the fourth Mg site, Mg(4) is bonded to one O(1), one O(3), one O(5), one O(7), one O(8), and one O(9) atom to form distorted MgO6 octahedra that share corners with two equivalent Sb(2)O6 octahedra, corners with three equivalent Sb(1)O6 octahedra, corners with four equivalent Mg(2)O6 octahedra, edges with two equivalent Mg(3)O6 octahedra, and  a faceface with one Sb(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 44-63°. There are two inequivalent Sb sites. In the first Sb site, Sb(1) is bonded to one O(2), one O(5), two equivalent O(4), and two equivalent O(7) atoms to form SbO6 octahedra that share  a cornercorner with one Mg(3)O6 octahedra, corners with three equivalent Mg(4)O6 octahedra,  an edgeedge with one Mg(2)O6 octahedra, and edges with two equivalent Sb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-63°. In the second Sb site, Sb(2) is bonded to one O(1), one O(3), one O(6), one O(9), and two equivalent O(8) atoms to form SbO6 octahedra that share corners with two equivalent Mg(4)O6 octahedra, corners with six equivalent Mg(3)O6 octahedra,  an edgeedge with one Sb(2)O6 octahedra, edges with two equivalent Mg(2)O6 octahedra, and  a faceface with one Mg(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 43-60°. There are nine inequivalent O sites. In the first O site, O(1) is bonded to one Mg(2), one Mg(3), one Mg(4), and one Sb(2) atom to form distorted OMg3Sb trigonal pyramids that share  a cornercorner with one O(7)Mg2Sb2 trigonal pyramid,  a cornercorner with one O(5)Mg3Sb trigonal pyramid, corners with three equivalent O(3)Mg3Sb trigonal pyramids, corners with four equivalent O(8)Mg2Sb2 trigonal pyramids, and  an edgeedge with one O(5)Mg3Sb trigonal pyramid. In the second O site, O(2) is bonded in a distorted see-saw-like geometry to one Mg(2), two equivalent Mg(1), and one Sb(1) atom. In the third O site, O(3) is bonded to one Mg(1), one Mg(2), one Mg(4), and one Sb(2) atom to form distorted OMg3Sb trigonal pyramids that share  a cornercorner with one O(8)Mg2Sb2 trigonal pyramid, corners with two equivalent O(4)Mg2Sb2 trigonal pyramids, corners with two equivalent O(5)Mg3Sb trigonal pyramids, corners with three equivalent O(1)Mg3Sb trigonal pyramids,  an edgeedge with one O(7)Mg2Sb2 trigonal pyramid, and  an edgeedge with one O(8)Mg2Sb2 trigonal pyramid. In the fourth O site, O(4) is bonded to two equivalent Mg(1) and two equivalent Sb(1) atoms to form distorted OMg2Sb2 trigonal pyramids that share corners with two equivalent O(3)Mg3Sb trigonal pyramids, corners with two equivalent O(5)Mg3Sb trigonal pyramids, corners with four equivalent O(7)Mg2Sb2 trigonal pyramids,  an edgeedge with one O(7)Mg2Sb2 trigonal pyramid, and edges with two equivalent O(4)Mg2Sb2 trigonal pyramids. In the fifth O site, O(5) is bonded to one Mg(2), one Mg(3), one Mg(4), and one Sb(1) atom to form distorted OMg3Sb trigonal pyramids that share  a cornercorner with one O(1)Mg3Sb trigonal pyramid, corners with two equivalent O(4)Mg2Sb2 trigonal pyramids, corners with two equivalent O(3)Mg3Sb trigonal pyramids, corners with three equivalent O(7)Mg2Sb2 trigonal pyramids,  an edgeedge with one O(8)Mg2Sb2 trigonal pyramid, and  an edgeedge with one O(1)Mg3Sb trigonal pyramid. In the sixth O site, O(6) is bonded in a distorted see-saw-like geometry to one Mg(2), two equivalent Mg(3), and one Sb(2) atom. In the seventh O site, O(7) is bonded to one Mg(1), one Mg(4), and two equivalent Sb(1) atoms to form distorted OMg2Sb2 trigonal pyramids that share  a cornercorner with one O(8)Mg2Sb2 trigonal pyramid,  a cornercorner with one O(1)Mg3Sb trigonal pyramid, corners with three equivalent O(5)Mg3Sb trigonal pyramids, corners with four equivalent O(4)Mg2Sb2 trigonal pyramids,  an edgeedge with one O(4)Mg2Sb2 trigonal pyramid,  an edgeedge with one O(7)Mg2Sb2 trigonal pyramid, and  an edgeedge with one O(3)Mg3Sb trigonal pyramid. In the eighth O site, O(8) is bonded to one Mg(3), one Mg(4), and two equivalent Sb(2) atoms to form distorted OMg2Sb2 trigonal pyramids that share  a cornercorner with one O(7)Mg2Sb2 trigonal pyramid,  a cornercorner with one O(3)Mg3Sb trigonal pyramid, corners with four equivalent O(1)Mg3Sb trigonal pyramids,  an edgeedge with one O(8)Mg2Sb2 trigonal pyramid,  an edgeedge with one O(3)Mg3Sb trigonal pyramid, and  an edgeedge with one O(5)Mg3Sb trigonal pyramid. In the ninth O site, O(9) is bonded in a distorted see-saw-like geometry to one Mg(2), one Mg(3), one Mg(4), and one Sb(2) atom. is represented by the CIF file [CIF]
data_Mg4Sb2O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.179
_cell_length_b   5.563
_cell_length_c   11.707
_cell_angle_alpha   98.163
_cell_angle_beta   102.739
_cell_angle_gamma   90.744
_symmetry_Int_Tables_number   1
_cell_volume   325.307
_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
  Mg  Mg0  1  0.225  0.484  0.420  1.0
  Mg  Mg1  1  0.617  0.330  0.230  1.0
  Mg  Mg2  1  0.537  0.844  0.097  1.0
  Mg  Mg3  1  0.112  0.830  0.233  1.0
  Mg  Mg4  1  0.888  0.170  0.767  1.0
  Mg  Mg5  1  0.463  0.156  0.903  1.0
  Mg  Mg6  1  0.383  0.670  0.770  1.0
  Mg  Mg7  1  0.775  0.516  0.580  1.0
  Sb  Sb8  1  0.286  0.969  0.573  1.0
  Sb  Sb9  1  0.943  0.650  0.894  1.0
  Sb  Sb10  1  0.057  0.350  0.106  1.0
  Sb  Sb11  1  0.714  0.031  0.427  1.0
  O  O12  1  0.725  0.906  0.834  1.0
  O  O13  1  0.425  0.651  0.596  1.0
  O  O14  1  0.983  0.483  0.263  1.0
  O  O15  1  0.064  0.229  0.502  1.0
  O  O16  1  0.780  0.977  0.272  1.0
  O  O17  1  0.292  0.819  0.933  1.0
  O  O18  1  0.360  0.865  0.404  1.0
  O  O19  1  0.878  0.672  0.058  1.0
  O  O20  1  0.373  0.581  0.166  1.0
  O  O21  1  0.627  0.419  0.834  1.0
  O  O22  1  0.122  0.328  0.942  1.0
  O  O23  1  0.640  0.135  0.596  1.0
  O  O24  1  0.708  0.181  0.067  1.0
  O  O25  1  0.220  0.023  0.728  1.0
  O  O26  1  0.936  0.771  0.498  1.0
  O  O27  1  0.017  0.517  0.737  1.0
  O  O28  1  0.575  0.349  0.404  1.0
  O  O29  1  0.275  0.094  0.166  1.0
[/CIF]
.
The material structure described by Mg4Sb2O9 is Ilmenite-like structured and crystallizes in the triclinic P-1 space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 6-coordinate geometry to one O(3), one O(7), two equivalent O(2), and two equivalent O(4) atoms. In the second Mg site, Mg(2) is bonded to one O(1), one O(2), one O(3), one O(5), one O(6), and one O(9) atom to form distorted MgO6 octahedra that share corners with two equivalent Mg(3)O6 octahedra, corners with four equivalent Mg(4)O6 octahedra,  an edgeedge with one Sb(1)O6 octahedra, edges with two equivalent Sb(2)O6 octahedra, and  a faceface with one Mg(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 44-64°. In the third Mg site, Mg(3) is bonded to one O(1), one O(5), one O(8), one O(9), and two equivalent O(6) atoms to form MgO6 octahedra that share  a cornercorner with one Sb(1)O6 octahedra, corners with two equivalent Mg(2)O6 octahedra, corners with six equivalent Sb(2)O6 octahedra,  an edgeedge with one Mg(3)O6 octahedra, edges with two equivalent Mg(4)O6 octahedra, and  a faceface with one Mg(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 43-64°. In the fourth Mg site, Mg(4) is bonded to one O(1), one O(3), one O(5), one O(7), one O(8), and one O(9) atom to form distorted MgO6 octahedra that share corners with two equivalent Sb(2)O6 octahedra, corners with three equivalent Sb(1)O6 octahedra, corners with four equivalent Mg(2)O6 octahedra, edges with two equivalent Mg(3)O6 octahedra, and  a faceface with one Sb(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 44-63°. There are two inequivalent Sb sites. In the first Sb site, Sb(1) is bonded to one O(2), one O(5), two equivalent O(4), and two equivalent O(7) atoms to form SbO6 octahedra that share  a cornercorner with one Mg(3)O6 octahedra, corners with three equivalent Mg(4)O6 octahedra,  an edgeedge with one Mg(2)O6 octahedra, and edges with two equivalent Sb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-63°. In the second Sb site, Sb(2) is bonded to one O(1), one O(3), one O(6), one O(9), and two equivalent O(8) atoms to form SbO6 octahedra that share corners with two equivalent Mg(4)O6 octahedra, corners with six equivalent Mg(3)O6 octahedra,  an edgeedge with one Sb(2)O6 octahedra, edges with two equivalent Mg(2)O6 octahedra, and  a faceface with one Mg(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 43-60°. There are nine inequivalent O sites. In the first O site, O(1) is bonded to one Mg(2), one Mg(3), one Mg(4), and one Sb(2) atom to form distorted OMg3Sb trigonal pyramids that share  a cornercorner with one O(7)Mg2Sb2 trigonal pyramid,  a cornercorner with one O(5)Mg3Sb trigonal pyramid, corners with three equivalent O(3)Mg3Sb trigonal pyramids, corners with four equivalent O(8)Mg2Sb2 trigonal pyramids, and  an edgeedge with one O(5)Mg3Sb trigonal pyramid. In the second O site, O(2) is bonded in a distorted see-saw-like geometry to one Mg(2), two equivalent Mg(1), and one Sb(1) atom. In the third O site, O(3) is bonded to one Mg(1), one Mg(2), one Mg(4), and one Sb(2) atom to form distorted OMg3Sb trigonal pyramids that share  a cornercorner with one O(8)Mg2Sb2 trigonal pyramid, corners with two equivalent O(4)Mg2Sb2 trigonal pyramids, corners with two equivalent O(5)Mg3Sb trigonal pyramids, corners with three equivalent O(1)Mg3Sb trigonal pyramids,  an edgeedge with one O(7)Mg2Sb2 trigonal pyramid, and  an edgeedge with one O(8)Mg2Sb2 trigonal pyramid. In the fourth O site, O(4) is bonded to two equivalent Mg(1) and two equivalent Sb(1) atoms to form distorted OMg2Sb2 trigonal pyramids that share corners with two equivalent O(3)Mg3Sb trigonal pyramids, corners with two equivalent O(5)Mg3Sb trigonal pyramids, corners with four equivalent O(7)Mg2Sb2 trigonal pyramids,  an edgeedge with one O(7)Mg2Sb2 trigonal pyramid, and edges with two equivalent O(4)Mg2Sb2 trigonal pyramids. In the fifth O site, O(5) is bonded to one Mg(2), one Mg(3), one Mg(4), and one Sb(1) atom to form distorted OMg3Sb trigonal pyramids that share  a cornercorner with one O(1)Mg3Sb trigonal pyramid, corners with two equivalent O(4)Mg2Sb2 trigonal pyramids, corners with two equivalent O(3)Mg3Sb trigonal pyramids, corners with three equivalent O(7)Mg2Sb2 trigonal pyramids,  an edgeedge with one O(8)Mg2Sb2 trigonal pyramid, and  an edgeedge with one O(1)Mg3Sb trigonal pyramid. In the sixth O site, O(6) is bonded in a distorted see-saw-like geometry to one Mg(2), two equivalent Mg(3), and one Sb(2) atom. In the seventh O site, O(7) is bonded to one Mg(1), one Mg(4), and two equivalent Sb(1) atoms to form distorted OMg2Sb2 trigonal pyramids that share  a cornercorner with one O(8)Mg2Sb2 trigonal pyramid,  a cornercorner with one O(1)Mg3Sb trigonal pyramid, corners with three equivalent O(5)Mg3Sb trigonal pyramids, corners with four equivalent O(4)Mg2Sb2 trigonal pyramids,  an edgeedge with one O(4)Mg2Sb2 trigonal pyramid,  an edgeedge with one O(7)Mg2Sb2 trigonal pyramid, and  an edgeedge with one O(3)Mg3Sb trigonal pyramid. In the eighth O site, O(8) is bonded to one Mg(3), one Mg(4), and two equivalent Sb(2) atoms to form distorted OMg2Sb2 trigonal pyramids that share  a cornercorner with one O(7)Mg2Sb2 trigonal pyramid,  a cornercorner with one O(3)Mg3Sb trigonal pyramid, corners with four equivalent O(1)Mg3Sb trigonal pyramids,  an edgeedge with one O(8)Mg2Sb2 trigonal pyramid,  an edgeedge with one O(3)Mg3Sb trigonal pyramid, and  an edgeedge with one O(5)Mg3Sb trigonal pyramid. In the ninth O site, O(9) is bonded in a distorted see-saw-like geometry to one Mg(2), one Mg(3), one Mg(4), and one Sb(2) atom. is represented by the CIF file [CIF]
data_Mg4Sb2O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.179
_cell_length_b   5.563
_cell_length_c   11.707
_cell_angle_alpha   98.163
_cell_angle_beta   102.739
_cell_angle_gamma   90.744
_symmetry_Int_Tables_number   1
_cell_volume   325.307
_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
  Mg  Mg0  1  0.225  0.484  0.420  1.0
  Mg  Mg1  1  0.617  0.330  0.230  1.0
  Mg  Mg2  1  0.537  0.844  0.097  1.0
  Mg  Mg3  1  0.112  0.830  0.233  1.0
  Mg  Mg4  1  0.888  0.170  0.767  1.0
  Mg  Mg5  1  0.463  0.156  0.903  1.0
  Mg  Mg6  1  0.383  0.670  0.770  1.0
  Mg  Mg7  1  0.775  0.516  0.580  1.0
  Sb  Sb8  1  0.286  0.969  0.573  1.0
  Sb  Sb9  1  0.943  0.650  0.894  1.0
  Sb  Sb10  1  0.057  0.350  0.106  1.0
  Sb  Sb11  1  0.714  0.031  0.427  1.0
  O  O12  1  0.725  0.906  0.834  1.0
  O  O13  1  0.425  0.651  0.596  1.0
  O  O14  1  0.983  0.483  0.263  1.0
  O  O15  1  0.064  0.229  0.502  1.0
  O  O16  1  0.780  0.977  0.272  1.0
  O  O17  1  0.292  0.819  0.933  1.0
  O  O18  1  0.360  0.865  0.404  1.0
  O  O19  1  0.878  0.672  0.058  1.0
  O  O20  1  0.373  0.581  0.166  1.0
  O  O21  1  0.627  0.419  0.834  1.0
  O  O22  1  0.122  0.328  0.942  1.0
  O  O23  1  0.640  0.135  0.596  1.0
  O  O24  1  0.708  0.181  0.067  1.0
  O  O25  1  0.220  0.023  0.728  1.0
  O  O26  1  0.936  0.771  0.498  1.0
  O  O27  1  0.017  0.517  0.737  1.0
  O  O28  1  0.575  0.349  0.404  1.0
  O  O29  1  0.275  0.094  0.166  1.0
[/CIF]
.