The crystal structure described by Mg3Sn3(AsO4)4 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 4-coordinate geometry to one O(1), one O(3), one O(4), one O(5), and one O(7) atom. In the second Mg site, Mg(2) is bonded to two equivalent O(2), two equivalent O(6), and two equivalent O(8) atoms to form MgO6 octahedra that share corners with two equivalent As(2)O4 tetrahedra and corners with four equivalent As(1)O4 tetrahedra. There are two inequivalent Sn sites. In the first Sn site, Sn(1) is bonded in a distorted pentagonal planar geometry to one O(1), one O(2), one O(4), one O(7), and one O(8) atom. In the second Sn site, Sn(2) is bonded in a 6-coordinate geometry to two equivalent O(4), two equivalent O(5), and two equivalent O(7) atoms. There are two inequivalent As sites. In the first As site, As(1) is bonded to one O(1), one O(4), one O(6), and one O(8) atom to form AsO4 tetrahedra that share corners with two equivalent Mg(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 25-59°. In the second As site, As(2) is bonded to one O(2), one O(3), one O(5), and one O(7) atom to form AsO4 tetrahedra that share  a cornercorner with one Mg(2)O6 octahedra. The corner-sharing octahedral tilt angles are 53°. There are eight inequivalent O sites. In the first O site, O(7) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Sn(1), one Sn(2), and one As(2) atom. In the second O site, O(8) is bonded in a 3-coordinate geometry to one Mg(2), one Sn(1), and one As(1) atom. In the third O site, O(1) is bonded in a 3-coordinate geometry to one Mg(1), one Sn(1), and one As(1) atom. In the fourth O site, O(2) is bonded in a 3-coordinate geometry to one Mg(2), one Sn(1), and one As(2) atom. In the fifth O site, O(3) is bonded in a bent 150 degrees geometry to one Mg(1) and one As(2) atom. In the sixth O site, O(4) is bonded in a 4-coordinate geometry to one Mg(1), one Sn(1), one Sn(2), and one As(1) atom. In the seventh O site, O(5) is bonded in a 3-coordinate geometry to one Mg(1), one Sn(2), and one As(2) atom. In the eighth O site, O(6) is bonded in a bent 150 degrees geometry to one Mg(2) and one As(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Mg3Sn3(AsO4)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.548
_cell_length_b   9.185
_cell_length_c   17.810
_cell_angle_alpha   59.313
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   780.418
_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  0.566  0.325  0.221  1.0
  Mg  Mg1  1  0.066  0.675  0.279  1.0
  Mg  Mg2  1  0.434  0.675  0.779  1.0
  Mg  Mg3  1  0.934  0.325  0.721  1.0
  Mg  Mg4  1  0.500  0.000  0.500  1.0
  Mg  Mg5  1  0.000  0.000  0.000  1.0
  Sn  Sn6  1  0.541  0.170  0.635  1.0
  Sn  Sn7  1  0.459  0.830  0.365  1.0
  Sn  Sn8  1  0.041  0.830  0.865  1.0
  Sn  Sn9  1  0.959  0.170  0.135  1.0
  Sn  Sn10  1  0.000  0.500  0.500  1.0
  Sn  Sn11  1  0.500  0.500  0.000  1.0
  As  As12  1  0.994  0.018  0.367  1.0
  As  As13  1  0.540  0.436  0.380  1.0
  As  As14  1  0.040  0.564  0.120  1.0
  As  As15  1  0.960  0.436  0.880  1.0
  As  As16  1  0.006  0.982  0.633  1.0
  As  As17  1  0.460  0.564  0.620  1.0
  As  As18  1  0.506  0.018  0.867  1.0
  As  As19  1  0.494  0.982  0.133  1.0
  O  O20  1  0.343  0.851  0.231  1.0
  O  O21  1  0.062  0.750  0.022  1.0
  O  O22  1  0.474  0.423  0.291  1.0
  O  O23  1  0.552  0.176  0.130  1.0
  O  O24  1  0.526  0.577  0.709  1.0
  O  O25  1  0.157  0.851  0.731  1.0
  O  O26  1  0.974  0.577  0.209  1.0
  O  O27  1  0.709  0.560  0.867  1.0
  O  O28  1  0.687  0.993  0.947  1.0
  O  O29  1  0.657  0.149  0.769  1.0
  O  O30  1  0.948  0.176  0.630  1.0
  O  O31  1  0.291  0.440  0.133  1.0
  O  O32  1  0.303  0.555  0.389  1.0
  O  O33  1  0.313  0.007  0.053  1.0
  O  O34  1  0.707  0.924  0.633  1.0
  O  O35  1  0.207  0.076  0.867  1.0
  O  O36  1  0.803  0.445  0.111  1.0
  O  O37  1  0.026  0.423  0.791  1.0
  O  O38  1  0.187  0.007  0.553  1.0
  O  O39  1  0.209  0.440  0.633  1.0
  O  O40  1  0.793  0.924  0.133  1.0
  O  O41  1  0.293  0.076  0.367  1.0
  O  O42  1  0.938  0.250  0.978  1.0
  O  O43  1  0.562  0.250  0.478  1.0
  O  O44  1  0.697  0.445  0.611  1.0
  O  O45  1  0.843  0.149  0.269  1.0
  O  O46  1  0.448  0.824  0.870  1.0
  O  O47  1  0.813  0.993  0.447  1.0
  O  O48  1  0.438  0.750  0.522  1.0
  O  O49  1  0.791  0.560  0.367  1.0
  O  O50  1  0.197  0.555  0.889  1.0
  O  O51  1  0.052  0.824  0.370  1.0
[/CIF]
.
The crystal structure described by Mg3Sn3(AsO4)4 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 4-coordinate geometry to one O(1), one O(3), one O(4), one O(5), and one O(7) atom. In the second Mg site, Mg(2) is bonded to two equivalent O(2), two equivalent O(6), and two equivalent O(8) atoms to form MgO6 octahedra that share corners with two equivalent As(2)O4 tetrahedra and corners with four equivalent As(1)O4 tetrahedra. There are two inequivalent Sn sites. In the first Sn site, Sn(1) is bonded in a distorted pentagonal planar geometry to one O(1), one O(2), one O(4), one O(7), and one O(8) atom. In the second Sn site, Sn(2) is bonded in a 6-coordinate geometry to two equivalent O(4), two equivalent O(5), and two equivalent O(7) atoms. There are two inequivalent As sites. In the first As site, As(1) is bonded to one O(1), one O(4), one O(6), and one O(8) atom to form AsO4 tetrahedra that share corners with two equivalent Mg(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 25-59°. In the second As site, As(2) is bonded to one O(2), one O(3), one O(5), and one O(7) atom to form AsO4 tetrahedra that share  a cornercorner with one Mg(2)O6 octahedra. The corner-sharing octahedral tilt angles are 53°. There are eight inequivalent O sites. In the first O site, O(7) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Sn(1), one Sn(2), and one As(2) atom. In the second O site, O(8) is bonded in a 3-coordinate geometry to one Mg(2), one Sn(1), and one As(1) atom. In the third O site, O(1) is bonded in a 3-coordinate geometry to one Mg(1), one Sn(1), and one As(1) atom. In the fourth O site, O(2) is bonded in a 3-coordinate geometry to one Mg(2), one Sn(1), and one As(2) atom. In the fifth O site, O(3) is bonded in a bent 150 degrees geometry to one Mg(1) and one As(2) atom. In the sixth O site, O(4) is bonded in a 4-coordinate geometry to one Mg(1), one Sn(1), one Sn(2), and one As(1) atom. In the seventh O site, O(5) is bonded in a 3-coordinate geometry to one Mg(1), one Sn(2), and one As(2) atom. In the eighth O site, O(6) is bonded in a bent 150 degrees geometry to one Mg(2) and one As(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Mg3Sn3(AsO4)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.548
_cell_length_b   9.185
_cell_length_c   17.810
_cell_angle_alpha   59.313
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   780.418
_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  0.566  0.325  0.221  1.0
  Mg  Mg1  1  0.066  0.675  0.279  1.0
  Mg  Mg2  1  0.434  0.675  0.779  1.0
  Mg  Mg3  1  0.934  0.325  0.721  1.0
  Mg  Mg4  1  0.500  0.000  0.500  1.0
  Mg  Mg5  1  0.000  0.000  0.000  1.0
  Sn  Sn6  1  0.541  0.170  0.635  1.0
  Sn  Sn7  1  0.459  0.830  0.365  1.0
  Sn  Sn8  1  0.041  0.830  0.865  1.0
  Sn  Sn9  1  0.959  0.170  0.135  1.0
  Sn  Sn10  1  0.000  0.500  0.500  1.0
  Sn  Sn11  1  0.500  0.500  0.000  1.0
  As  As12  1  0.994  0.018  0.367  1.0
  As  As13  1  0.540  0.436  0.380  1.0
  As  As14  1  0.040  0.564  0.120  1.0
  As  As15  1  0.960  0.436  0.880  1.0
  As  As16  1  0.006  0.982  0.633  1.0
  As  As17  1  0.460  0.564  0.620  1.0
  As  As18  1  0.506  0.018  0.867  1.0
  As  As19  1  0.494  0.982  0.133  1.0
  O  O20  1  0.343  0.851  0.231  1.0
  O  O21  1  0.062  0.750  0.022  1.0
  O  O22  1  0.474  0.423  0.291  1.0
  O  O23  1  0.552  0.176  0.130  1.0
  O  O24  1  0.526  0.577  0.709  1.0
  O  O25  1  0.157  0.851  0.731  1.0
  O  O26  1  0.974  0.577  0.209  1.0
  O  O27  1  0.709  0.560  0.867  1.0
  O  O28  1  0.687  0.993  0.947  1.0
  O  O29  1  0.657  0.149  0.769  1.0
  O  O30  1  0.948  0.176  0.630  1.0
  O  O31  1  0.291  0.440  0.133  1.0
  O  O32  1  0.303  0.555  0.389  1.0
  O  O33  1  0.313  0.007  0.053  1.0
  O  O34  1  0.707  0.924  0.633  1.0
  O  O35  1  0.207  0.076  0.867  1.0
  O  O36  1  0.803  0.445  0.111  1.0
  O  O37  1  0.026  0.423  0.791  1.0
  O  O38  1  0.187  0.007  0.553  1.0
  O  O39  1  0.209  0.440  0.633  1.0
  O  O40  1  0.793  0.924  0.133  1.0
  O  O41  1  0.293  0.076  0.367  1.0
  O  O42  1  0.938  0.250  0.978  1.0
  O  O43  1  0.562  0.250  0.478  1.0
  O  O44  1  0.697  0.445  0.611  1.0
  O  O45  1  0.843  0.149  0.269  1.0
  O  O46  1  0.448  0.824  0.870  1.0
  O  O47  1  0.813  0.993  0.447  1.0
  O  O48  1  0.438  0.750  0.522  1.0
  O  O49  1  0.791  0.560  0.367  1.0
  O  O50  1  0.197  0.555  0.889  1.0
  O  O51  1  0.052  0.824  0.370  1.0
[/CIF]
.