The structure described by Mg2Sn9O13 crystallizes in the monoclinic C2/m space group. Mg(1) is bonded to one O(3), one O(6), two equivalent O(2), and two equivalent O(5) atoms to form MgO6 octahedra that share  a cornercorner with one Sn(1)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, and edges with two equivalent Sn(4)O6 octahedra. The corner-sharing octahedral tilt angles are 43°. There are five inequivalent Sn sites. In the first Sn site, Sn(1) is bonded to two equivalent O(6) and four equivalent O(7) atoms to form SnO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra and edges with two equivalent Sn(1)O6 octahedra. The corner-sharing octahedral tilt angles are 43°. In the second Sn site, Sn(2) is bonded in a water-like geometry to one O(4) and one O(5) atom. In the third Sn site, Sn(3) is bonded in a distorted T-shaped geometry to one O(5) and two equivalent O(6) atoms. In the fourth Sn site, Sn(4) is bonded to one O(1), one O(2), two equivalent O(3), and two equivalent O(4) atoms to form SnO6 octahedra that share  a cornercorner with one Sn(4)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, and edges with two equivalent Sn(4)O6 octahedra. The corner-sharing octahedra are not tilted. In the fifth Sn site, Sn(5) is bonded in an L-shaped geometry to one O(2) and one O(7) atom. There are seven inequivalent O sites. In the first O site, O(7) is bonded in a trigonal planar geometry to one Sn(5) and two equivalent Sn(1) atoms. In the second O site, O(1) is bonded in a linear geometry to two equivalent Sn(4) atoms. In the third O site, O(2) is bonded to two equivalent Mg(1), one Sn(4), and one Sn(5) atom to form a mixture of distorted corner and edge-sharing OMg2Sn2 tetrahedra. In the fourth O site, O(3) is bonded in a distorted trigonal non-coplanar geometry to one Mg(1) and two equivalent Sn(4) atoms. In the fifth O site, O(4) is bonded in a trigonal non-coplanar geometry to one Sn(2) and two equivalent Sn(4) atoms. In the sixth O site, O(5) is bonded to two equivalent Mg(1), one Sn(2), and one Sn(3) atom to form a mixture of distorted corner and edge-sharing OMg2Sn2 tetrahedra. In the seventh O site, O(6) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Sn(1), and two equivalent Sn(3) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Mg2Sn9O13
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.191
_cell_length_b   8.191
_cell_length_c   15.782
_cell_angle_alpha   72.921
_cell_angle_beta   72.921
_cell_angle_gamma   22.534
_symmetry_Int_Tables_number   1
_cell_volume   387.144
_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
  Mg  Mg0  1  0.372  0.372  0.764  1.0
  Mg  Mg1  1  0.628  0.628  0.236  1.0
  Sn  Sn2  1  0.500  0.500  0.500  1.0
  Sn  Sn3  1  0.674  0.674  0.889  1.0
  Sn  Sn4  1  0.326  0.326  0.111  1.0
  Sn  Sn5  1  0.795  0.795  0.623  1.0
  Sn  Sn6  1  0.205  0.205  0.377  1.0
  Sn  Sn7  1  0.968  0.968  0.887  1.0
  Sn  Sn8  1  0.032  0.032  0.113  1.0
  Sn  Sn9  1  0.089  0.089  0.673  1.0
  Sn  Sn10  1  0.911  0.911  0.327  1.0
  O  O11  1  0.000  0.000  0.000  1.0
  O  O12  1  0.959  0.959  0.753  1.0
  O  O13  1  0.041  0.041  0.247  1.0
  O  O14  1  0.382  0.382  0.903  1.0
  O  O15  1  0.618  0.618  0.097  1.0
  O  O16  1  0.564  0.564  0.837  1.0
  O  O17  1  0.436  0.436  0.163  1.0
  O  O18  1  0.783  0.783  0.761  1.0
  O  O19  1  0.217  0.217  0.239  1.0
  O  O20  1  0.392  0.392  0.617  1.0
  O  O21  1  0.608  0.608  0.383  1.0
  O  O22  1  0.060  0.060  0.547  1.0
  O  O23  1  0.940  0.940  0.453  1.0
[/CIF]
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The structure described by Mg2Sn9O13 crystallizes in the monoclinic C2/m space group. Mg(1) is bonded to one O(3), one O(6), two equivalent O(2), and two equivalent O(5) atoms to form MgO6 octahedra that share  a cornercorner with one Sn(1)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, and edges with two equivalent Sn(4)O6 octahedra. The corner-sharing octahedral tilt angles are 43°. There are five inequivalent Sn sites. In the first Sn site, Sn(1) is bonded to two equivalent O(6) and four equivalent O(7) atoms to form SnO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra and edges with two equivalent Sn(1)O6 octahedra. The corner-sharing octahedral tilt angles are 43°. In the second Sn site, Sn(2) is bonded in a water-like geometry to one O(4) and one O(5) atom. In the third Sn site, Sn(3) is bonded in a distorted T-shaped geometry to one O(5) and two equivalent O(6) atoms. In the fourth Sn site, Sn(4) is bonded to one O(1), one O(2), two equivalent O(3), and two equivalent O(4) atoms to form SnO6 octahedra that share  a cornercorner with one Sn(4)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, and edges with two equivalent Sn(4)O6 octahedra. The corner-sharing octahedra are not tilted. In the fifth Sn site, Sn(5) is bonded in an L-shaped geometry to one O(2) and one O(7) atom. There are seven inequivalent O sites. In the first O site, O(7) is bonded in a trigonal planar geometry to one Sn(5) and two equivalent Sn(1) atoms. In the second O site, O(1) is bonded in a linear geometry to two equivalent Sn(4) atoms. In the third O site, O(2) is bonded to two equivalent Mg(1), one Sn(4), and one Sn(5) atom to form a mixture of distorted corner and edge-sharing OMg2Sn2 tetrahedra. In the fourth O site, O(3) is bonded in a distorted trigonal non-coplanar geometry to one Mg(1) and two equivalent Sn(4) atoms. In the fifth O site, O(4) is bonded in a trigonal non-coplanar geometry to one Sn(2) and two equivalent Sn(4) atoms. In the sixth O site, O(5) is bonded to two equivalent Mg(1), one Sn(2), and one Sn(3) atom to form a mixture of distorted corner and edge-sharing OMg2Sn2 tetrahedra. In the seventh O site, O(6) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Sn(1), and two equivalent Sn(3) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Mg2Sn9O13
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.191
_cell_length_b   8.191
_cell_length_c   15.782
_cell_angle_alpha   72.921
_cell_angle_beta   72.921
_cell_angle_gamma   22.534
_symmetry_Int_Tables_number   1
_cell_volume   387.144
_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
  Mg  Mg0  1  0.372  0.372  0.764  1.0
  Mg  Mg1  1  0.628  0.628  0.236  1.0
  Sn  Sn2  1  0.500  0.500  0.500  1.0
  Sn  Sn3  1  0.674  0.674  0.889  1.0
  Sn  Sn4  1  0.326  0.326  0.111  1.0
  Sn  Sn5  1  0.795  0.795  0.623  1.0
  Sn  Sn6  1  0.205  0.205  0.377  1.0
  Sn  Sn7  1  0.968  0.968  0.887  1.0
  Sn  Sn8  1  0.032  0.032  0.113  1.0
  Sn  Sn9  1  0.089  0.089  0.673  1.0
  Sn  Sn10  1  0.911  0.911  0.327  1.0
  O  O11  1  0.000  0.000  0.000  1.0
  O  O12  1  0.959  0.959  0.753  1.0
  O  O13  1  0.041  0.041  0.247  1.0
  O  O14  1  0.382  0.382  0.903  1.0
  O  O15  1  0.618  0.618  0.097  1.0
  O  O16  1  0.564  0.564  0.837  1.0
  O  O17  1  0.436  0.436  0.163  1.0
  O  O18  1  0.783  0.783  0.761  1.0
  O  O19  1  0.217  0.217  0.239  1.0
  O  O20  1  0.392  0.392  0.617  1.0
  O  O21  1  0.608  0.608  0.383  1.0
  O  O22  1  0.060  0.060  0.547  1.0
  O  O23  1  0.940  0.940  0.453  1.0
[/CIF]
.