The material structure described by Mg3SiO4F2 is beta indium sulfide-derived structured and crystallizes in the orthorhombic Pnma space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one O(2), one O(3), two equivalent O(1), and two equivalent F(1) atoms to form MgO4F2 octahedra that share corners with two equivalent Mg(1)O4F2 octahedra, corners with four equivalent Mg(2)O4F2 octahedra, corners with two equivalent Si(1)O4 tetrahedra,  an edgeedge with one Mg(2)O4F2 octahedra, edges with two equivalent Mg(1)O4F2 octahedra, and  an edgeedge with one Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 49-59°. In the second Mg site, Mg(2) is bonded to one O(2), one O(3), two equivalent O(1), and two equivalent F(1) atoms to form MgO4F2 octahedra that share corners with eight equivalent Mg(1)O4F2 octahedra, corners with two equivalent Si(1)O4 tetrahedra, edges with two equivalent Mg(1)O4F2 octahedra, and  an edgeedge with one Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 49-57°. Si(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form SiO4 tetrahedra that share corners with two equivalent Mg(2)O4F2 octahedra, corners with four equivalent Mg(1)O4F2 octahedra,  an edgeedge with one Mg(2)O4F2 octahedra, and edges with two equivalent Mg(1)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 56-60°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to one Mg(2), two equivalent Mg(1), and one Si(1) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Mg(2), two equivalent Mg(1), and one Si(1) atom. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to one Mg(2), two equivalent Mg(1), and one Si(1) atom. F(1) is bonded in a distorted trigonal planar geometry to one Mg(2) and two equivalent Mg(1) atoms. is represented by the CIF card [CIF]
data_Mg3Si(O2F)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.760
_cell_length_b   8.842
_cell_length_c   10.391
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   437.355
_cell_formula_units_Z   4
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  0.990  0.430  0.367  1.0
  Mg  Mg1  1  0.994  0.250  0.093  1.0
  Mg  Mg2  1  0.510  0.070  0.867  1.0
  Mg  Mg3  1  0.990  0.070  0.367  1.0
  Mg  Mg4  1  0.006  0.750  0.907  1.0
  Mg  Mg5  1  0.506  0.250  0.593  1.0
  Mg  Mg6  1  0.010  0.930  0.633  1.0
  Mg  Mg7  1  0.510  0.430  0.867  1.0
  Mg  Mg8  1  0.494  0.750  0.407  1.0
  Mg  Mg9  1  0.010  0.570  0.633  1.0
  Mg  Mg10  1  0.490  0.570  0.133  1.0
  Mg  Mg11  1  0.490  0.930  0.133  1.0
  Si  Si12  1  0.080  0.250  0.780  1.0
  Si  Si13  1  0.420  0.250  0.280  1.0
  Si  Si14  1  0.920  0.750  0.220  1.0
  Si  Si15  1  0.580  0.750  0.720  1.0
  O  O16  1  0.732  0.897  0.791  1.0
  O  O17  1  0.268  0.103  0.209  1.0
  O  O18  1  0.238  0.750  0.721  1.0
  O  O19  1  0.778  0.750  0.074  1.0
  O  O20  1  0.278  0.250  0.426  1.0
  O  O21  1  0.722  0.750  0.574  1.0
  O  O22  1  0.768  0.897  0.291  1.0
  O  O23  1  0.762  0.250  0.279  1.0
  O  O24  1  0.268  0.397  0.209  1.0
  O  O25  1  0.732  0.603  0.791  1.0
  O  O26  1  0.262  0.750  0.221  1.0
  O  O27  1  0.232  0.103  0.709  1.0
  O  O28  1  0.222  0.250  0.926  1.0
  O  O29  1  0.768  0.603  0.291  1.0
  O  O30  1  0.738  0.250  0.779  1.0
  O  O31  1  0.232  0.397  0.709  1.0
  F  F32  1  0.272  0.916  0.967  1.0
  F  F33  1  0.228  0.584  0.467  1.0
  F  F34  1  0.728  0.084  0.033  1.0
  F  F35  1  0.728  0.416  0.033  1.0
  F  F36  1  0.772  0.416  0.533  1.0
  F  F37  1  0.228  0.916  0.467  1.0
  F  F38  1  0.772  0.084  0.533  1.0
  F  F39  1  0.272  0.584  0.967  1.0
[/CIF]
.
The material structure described by Mg3SiO4F2 is beta indium sulfide-derived structured and crystallizes in the orthorhombic Pnma space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one O(2), one O(3), two equivalent O(1), and two equivalent F(1) atoms to form MgO4F2 octahedra that share corners with two equivalent Mg(1)O4F2 octahedra, corners with four equivalent Mg(2)O4F2 octahedra, corners with two equivalent Si(1)O4 tetrahedra,  an edgeedge with one Mg(2)O4F2 octahedra, edges with two equivalent Mg(1)O4F2 octahedra, and  an edgeedge with one Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 49-59°. In the second Mg site, Mg(2) is bonded to one O(2), one O(3), two equivalent O(1), and two equivalent F(1) atoms to form MgO4F2 octahedra that share corners with eight equivalent Mg(1)O4F2 octahedra, corners with two equivalent Si(1)O4 tetrahedra, edges with two equivalent Mg(1)O4F2 octahedra, and  an edgeedge with one Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 49-57°. Si(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form SiO4 tetrahedra that share corners with two equivalent Mg(2)O4F2 octahedra, corners with four equivalent Mg(1)O4F2 octahedra,  an edgeedge with one Mg(2)O4F2 octahedra, and edges with two equivalent Mg(1)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 56-60°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to one Mg(2), two equivalent Mg(1), and one Si(1) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Mg(2), two equivalent Mg(1), and one Si(1) atom. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to one Mg(2), two equivalent Mg(1), and one Si(1) atom. F(1) is bonded in a distorted trigonal planar geometry to one Mg(2) and two equivalent Mg(1) atoms. is represented by the CIF card [CIF]
data_Mg3Si(O2F)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.760
_cell_length_b   8.842
_cell_length_c   10.391
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   437.355
_cell_formula_units_Z   4
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  0.990  0.430  0.367  1.0
  Mg  Mg1  1  0.994  0.250  0.093  1.0
  Mg  Mg2  1  0.510  0.070  0.867  1.0
  Mg  Mg3  1  0.990  0.070  0.367  1.0
  Mg  Mg4  1  0.006  0.750  0.907  1.0
  Mg  Mg5  1  0.506  0.250  0.593  1.0
  Mg  Mg6  1  0.010  0.930  0.633  1.0
  Mg  Mg7  1  0.510  0.430  0.867  1.0
  Mg  Mg8  1  0.494  0.750  0.407  1.0
  Mg  Mg9  1  0.010  0.570  0.633  1.0
  Mg  Mg10  1  0.490  0.570  0.133  1.0
  Mg  Mg11  1  0.490  0.930  0.133  1.0
  Si  Si12  1  0.080  0.250  0.780  1.0
  Si  Si13  1  0.420  0.250  0.280  1.0
  Si  Si14  1  0.920  0.750  0.220  1.0
  Si  Si15  1  0.580  0.750  0.720  1.0
  O  O16  1  0.732  0.897  0.791  1.0
  O  O17  1  0.268  0.103  0.209  1.0
  O  O18  1  0.238  0.750  0.721  1.0
  O  O19  1  0.778  0.750  0.074  1.0
  O  O20  1  0.278  0.250  0.426  1.0
  O  O21  1  0.722  0.750  0.574  1.0
  O  O22  1  0.768  0.897  0.291  1.0
  O  O23  1  0.762  0.250  0.279  1.0
  O  O24  1  0.268  0.397  0.209  1.0
  O  O25  1  0.732  0.603  0.791  1.0
  O  O26  1  0.262  0.750  0.221  1.0
  O  O27  1  0.232  0.103  0.709  1.0
  O  O28  1  0.222  0.250  0.926  1.0
  O  O29  1  0.768  0.603  0.291  1.0
  O  O30  1  0.738  0.250  0.779  1.0
  O  O31  1  0.232  0.397  0.709  1.0
  F  F32  1  0.272  0.916  0.967  1.0
  F  F33  1  0.228  0.584  0.467  1.0
  F  F34  1  0.728  0.084  0.033  1.0
  F  F35  1  0.728  0.416  0.033  1.0
  F  F36  1  0.772  0.416  0.533  1.0
  F  F37  1  0.228  0.916  0.467  1.0
  F  F38  1  0.772  0.084  0.533  1.0
  F  F39  1  0.272  0.584  0.967  1.0
[/CIF]
.