The material described by Fe7(SiO6)2 is Spinel-like structured and crystallizes in the tetragonal I4_1/amd space group. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent O(3) and four equivalent O(1) atoms to form FeO6 octahedra that share corners with two equivalent Fe(3)O4 tetrahedra, corners with four equivalent Si(1)O4 tetrahedra, edges with two equivalent Fe(1)O6 octahedra, and edges with four equivalent Fe(2)O6 octahedra. In the second Fe site, Fe(2) is bonded to one O(1), two equivalent O(3), and three equivalent O(2) atoms to form FeO6 octahedra that share corners with two equivalent Fe(3)O4 tetrahedra, corners with four equivalent Si(1)O4 tetrahedra, edges with two equivalent Fe(1)O6 octahedra, and edges with four equivalent Fe(2)O6 octahedra. In the third Fe site, Fe(3) is bonded to four equivalent O(3) atoms to form corner-sharing FeO4 tetrahedra. The corner-sharing octahedral tilt angles range from 56-59°. Si(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form SiO4 tetrahedra that share corners with four equivalent Fe(1)O6 octahedra and corners with eight equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-52°. 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 Fe(2), two equivalent Fe(1), and one Si(1) atom. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to three equivalent Fe(2) and one Si(1) atom. In the third O site, O(3) is bonded to one Fe(1), one Fe(3), and two equivalent Fe(2) atoms to form a mixture of distorted corner and edge-sharing OFe4 trigonal pyramids. is represented by the CIF card [CIF]
data_Fe7(SiO6)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   13.243
_cell_length_b   13.243
_cell_length_c   13.243
_cell_angle_alpha   154.198
_cell_angle_beta   154.198
_cell_angle_gamma   36.812
_symmetry_Int_Tables_number   1
_cell_volume   439.395
_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
  Fe  Fe0  1  0.875  0.125  0.750  1.0
  Fe  Fe1  1  0.375  0.125  0.250  1.0
  Fe  Fe2  1  0.208  0.952  0.745  1.0
  Fe  Fe3  1  0.208  0.463  0.255  1.0
  Fe  Fe4  1  0.750  0.250  0.500  1.0
  Fe  Fe5  1  0.048  0.792  0.255  1.0
  Fe  Fe6  1  0.537  0.792  0.745  1.0
  Fe  Fe7  1  0.875  0.625  0.750  1.0
  Fe  Fe8  1  0.875  0.125  0.250  1.0
  Fe  Fe9  1  0.213  0.458  0.755  1.0
  Fe  Fe10  1  0.702  0.458  0.245  1.0
  Fe  Fe11  1  0.000  0.000  0.000  1.0
  Fe  Fe12  1  0.542  0.298  0.755  1.0
  Fe  Fe13  1  0.542  0.787  0.245  1.0
  Si  Si14  1  0.082  0.582  0.500  1.0
  Si  Si15  1  0.668  0.668  0.000  1.0
  Si  Si16  1  0.332  0.332  0.000  1.0
  Si  Si17  1  0.418  0.918  0.500  1.0
  O  O18  1  0.120  0.848  0.728  1.0
  O  O19  1  0.120  0.392  0.272  1.0
  O  O20  1  0.630  0.402  0.772  1.0
  O  O21  1  0.630  0.858  0.228  1.0
  O  O22  1  0.474  0.706  0.768  1.0
  O  O23  1  0.938  0.706  0.232  1.0
  O  O24  1  0.439  0.204  0.235  1.0
  O  O25  1  0.970  0.204  0.765  1.0
  O  O26  1  0.796  0.030  0.235  1.0
  O  O27  1  0.796  0.561  0.765  1.0
  O  O28  1  0.294  0.062  0.768  1.0
  O  O29  1  0.294  0.526  0.232  1.0
  O  O30  1  0.598  0.370  0.228  1.0
  O  O31  1  0.142  0.370  0.772  1.0
  O  O32  1  0.608  0.880  0.728  1.0
  O  O33  1  0.152  0.880  0.272  1.0
  O  O34  1  0.456  0.188  0.732  1.0
  O  O35  1  0.456  0.724  0.268  1.0
  O  O36  1  0.954  0.220  0.265  1.0
  O  O37  1  0.954  0.689  0.735  1.0
  O  O38  1  0.311  0.046  0.265  1.0
  O  O39  1  0.780  0.046  0.735  1.0
  O  O40  1  0.276  0.544  0.732  1.0
  O  O41  1  0.812  0.544  0.268  1.0
[/CIF]
.
The material described by Fe7(SiO6)2 is Spinel-like structured and crystallizes in the tetragonal I4_1/amd space group. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent O(3) and four equivalent O(1) atoms to form FeO6 octahedra that share corners with two equivalent Fe(3)O4 tetrahedra, corners with four equivalent Si(1)O4 tetrahedra, edges with two equivalent Fe(1)O6 octahedra, and edges with four equivalent Fe(2)O6 octahedra. In the second Fe site, Fe(2) is bonded to one O(1), two equivalent O(3), and three equivalent O(2) atoms to form FeO6 octahedra that share corners with two equivalent Fe(3)O4 tetrahedra, corners with four equivalent Si(1)O4 tetrahedra, edges with two equivalent Fe(1)O6 octahedra, and edges with four equivalent Fe(2)O6 octahedra. In the third Fe site, Fe(3) is bonded to four equivalent O(3) atoms to form corner-sharing FeO4 tetrahedra. The corner-sharing octahedral tilt angles range from 56-59°. Si(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form SiO4 tetrahedra that share corners with four equivalent Fe(1)O6 octahedra and corners with eight equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-52°. 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 Fe(2), two equivalent Fe(1), and one Si(1) atom. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to three equivalent Fe(2) and one Si(1) atom. In the third O site, O(3) is bonded to one Fe(1), one Fe(3), and two equivalent Fe(2) atoms to form a mixture of distorted corner and edge-sharing OFe4 trigonal pyramids. is represented by the CIF card [CIF]
data_Fe7(SiO6)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   13.243
_cell_length_b   13.243
_cell_length_c   13.243
_cell_angle_alpha   154.198
_cell_angle_beta   154.198
_cell_angle_gamma   36.812
_symmetry_Int_Tables_number   1
_cell_volume   439.395
_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
  Fe  Fe0  1  0.875  0.125  0.750  1.0
  Fe  Fe1  1  0.375  0.125  0.250  1.0
  Fe  Fe2  1  0.208  0.952  0.745  1.0
  Fe  Fe3  1  0.208  0.463  0.255  1.0
  Fe  Fe4  1  0.750  0.250  0.500  1.0
  Fe  Fe5  1  0.048  0.792  0.255  1.0
  Fe  Fe6  1  0.537  0.792  0.745  1.0
  Fe  Fe7  1  0.875  0.625  0.750  1.0
  Fe  Fe8  1  0.875  0.125  0.250  1.0
  Fe  Fe9  1  0.213  0.458  0.755  1.0
  Fe  Fe10  1  0.702  0.458  0.245  1.0
  Fe  Fe11  1  0.000  0.000  0.000  1.0
  Fe  Fe12  1  0.542  0.298  0.755  1.0
  Fe  Fe13  1  0.542  0.787  0.245  1.0
  Si  Si14  1  0.082  0.582  0.500  1.0
  Si  Si15  1  0.668  0.668  0.000  1.0
  Si  Si16  1  0.332  0.332  0.000  1.0
  Si  Si17  1  0.418  0.918  0.500  1.0
  O  O18  1  0.120  0.848  0.728  1.0
  O  O19  1  0.120  0.392  0.272  1.0
  O  O20  1  0.630  0.402  0.772  1.0
  O  O21  1  0.630  0.858  0.228  1.0
  O  O22  1  0.474  0.706  0.768  1.0
  O  O23  1  0.938  0.706  0.232  1.0
  O  O24  1  0.439  0.204  0.235  1.0
  O  O25  1  0.970  0.204  0.765  1.0
  O  O26  1  0.796  0.030  0.235  1.0
  O  O27  1  0.796  0.561  0.765  1.0
  O  O28  1  0.294  0.062  0.768  1.0
  O  O29  1  0.294  0.526  0.232  1.0
  O  O30  1  0.598  0.370  0.228  1.0
  O  O31  1  0.142  0.370  0.772  1.0
  O  O32  1  0.608  0.880  0.728  1.0
  O  O33  1  0.152  0.880  0.272  1.0
  O  O34  1  0.456  0.188  0.732  1.0
  O  O35  1  0.456  0.724  0.268  1.0
  O  O36  1  0.954  0.220  0.265  1.0
  O  O37  1  0.954  0.689  0.735  1.0
  O  O38  1  0.311  0.046  0.265  1.0
  O  O39  1  0.780  0.046  0.735  1.0
  O  O40  1  0.276  0.544  0.732  1.0
  O  O41  1  0.812  0.544  0.268  1.0
[/CIF]
.