The material structure described by Fe8SiO12 crystallizes in the monoclinic P2_1/m space group. There are seven inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent O(1), two equivalent O(4), and two equivalent O(8) atoms to form FeO6 octahedra that share corners with two equivalent Fe(3)O4 tetrahedra, corners with two equivalent Fe(4)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, edges with two equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(5)O6 octahedra, and edges with two equivalent Fe(7)O6 octahedra. In the second Fe site, Fe(2) is bonded to one O(2), one O(3), one O(5), one O(9), and two equivalent O(6) atoms to form FeO6 octahedra that share corners with two equivalent Fe(2)O6 octahedra,  a cornercorner with one Fe(4)O4 tetrahedra,  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent Fe(3)O4 tetrahedra,  an edgeedge with one Fe(5)O6 octahedra,  an edgeedge with one Fe(7)O6 octahedra, edges with two equivalent Fe(6)O6 octahedra, and edges with three equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles are 15°. In the third Fe site, Fe(3) is bonded to one O(5), one O(9), and two equivalent O(1) atoms to form corner-sharing FeO4 tetrahedra. The corner-sharing octahedral tilt angles range from 54-59°. In the fourth Fe site, Fe(4) is bonded to one O(4), one O(7), and two equivalent O(2) atoms to form FeO4 tetrahedra that share  a cornercorner with one Fe(5)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra, corners with two equivalent Fe(7)O6 octahedra, corners with three equivalent Fe(6)O6 octahedra, and  a cornercorner with one Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 52-68°. In the fifth Fe site, Fe(5) is bonded to one O(4), one O(5), two equivalent O(1), and two equivalent O(3) atoms to form FeO6 octahedra that share  a cornercorner with one Fe(4)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, corners with three equivalent Fe(3)O4 tetrahedra,  an edgeedge with one Fe(6)O6 octahedra,  an edgeedge with one Fe(7)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, and edges with two equivalent Fe(2)O6 octahedra. In the sixth Fe site, Fe(6) is bonded to one O(6), one O(7), two equivalent O(2), and two equivalent O(3) atoms to form FeO6 octahedra that share corners with three equivalent Fe(4)O4 tetrahedra, corners with three equivalent Si(1)O4 tetrahedra,  an edgeedge with one Fe(5)O6 octahedra,  an edgeedge with one Fe(7)O6 octahedra, and edges with four equivalent Fe(2)O6 octahedra. In the seventh Fe site, Fe(7) is bonded to one O(8), one O(9), two equivalent O(1), and two equivalent O(2) atoms to form FeO6 octahedra that share  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent Fe(4)O4 tetrahedra, corners with three equivalent Fe(3)O4 tetrahedra,  an edgeedge with one Fe(5)O6 octahedra,  an edgeedge with one Fe(6)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, and edges with two equivalent Fe(2)O6 octahedra. Si(1) is bonded to one O(7), one O(8), and two equivalent O(3) atoms to form SiO4 tetrahedra that share  a cornercorner with one Fe(7)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra, corners with two equivalent Fe(5)O6 octahedra, corners with three equivalent Fe(6)O6 octahedra, and  a cornercorner with one Fe(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 46-57°. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Fe(1), one Fe(3), one Fe(5), and one Fe(7) atom. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Fe(2), one Fe(4), one Fe(6), and one Fe(7) atom. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to one Fe(2), one Fe(5), one Fe(6), and one Si(1) atom. In the fourth O site, O(4) is bonded in a rectangular see-saw-like geometry to one Fe(4), one Fe(5), and two equivalent Fe(1) atoms. In the fifth O site, O(5) is bonded in a rectangular see-saw-like geometry to one Fe(3), one Fe(5), and two equivalent Fe(2) atoms. In the sixth O site, O(6) is bonded to one Fe(6) and four equivalent Fe(2) atoms to form edge-sharing OFe5 square pyramids. In the seventh O site, O(7) is bonded in a trigonal planar geometry to one Fe(4), one Fe(6), and one Si(1) atom. In the eighth O site, O(8) is bonded in a distorted rectangular see-saw-like geometry to one Fe(7), two equivalent Fe(1), and one Si(1) atom. In the ninth O site, O(9) is bonded in a rectangular see-saw-like geometry to one Fe(3), one Fe(7), and two equivalent Fe(2) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Fe8SiO12
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.003
_cell_length_b   8.484
_cell_length_c   9.120
_cell_angle_alpha   89.285
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   464.451
_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  0.000  0.000  0.000  1.0
  Fe  Fe1  1  0.987  0.495  0.663  1.0
  Fe  Fe2  1  0.013  0.505  0.337  1.0
  Fe  Fe3  1  0.250  0.619  0.991  1.0
  Fe  Fe4  1  0.250  0.865  0.676  1.0
  Fe  Fe5  1  0.250  0.248  0.835  1.0
  Fe  Fe6  1  0.250  0.217  0.501  1.0
  Fe  Fe7  1  0.250  0.246  0.166  1.0
  Fe  Fe8  1  0.500  0.000  0.000  1.0
  Fe  Fe9  1  0.487  0.505  0.337  1.0
  Fe  Fe10  1  0.513  0.495  0.663  1.0
  Fe  Fe11  1  0.750  0.381  0.009  1.0
  Fe  Fe12  1  0.750  0.754  0.834  1.0
  Fe  Fe13  1  0.750  0.783  0.499  1.0
  Fe  Fe14  1  0.750  0.135  0.324  1.0
  Fe  Fe15  1  0.750  0.752  0.165  1.0
  Si  Si16  1  0.250  0.869  0.328  1.0
  Si  Si17  1  0.750  0.131  0.672  1.0
  O  O18  1  0.011  0.249  0.011  1.0
  O  O19  1  0.986  0.740  0.673  1.0
  O  O20  1  0.023  0.755  0.331  1.0
  O  O21  1  0.250  0.004  0.838  1.0
  O  O22  1  0.250  0.491  0.818  1.0
  O  O23  1  0.250  0.471  0.508  1.0
  O  O24  1  0.250  0.972  0.483  1.0
  O  O25  1  0.250  0.993  0.186  1.0
  O  O26  1  0.250  0.492  0.171  1.0
  O  O27  1  0.514  0.740  0.673  1.0
  O  O28  1  0.477  0.755  0.331  1.0
  O  O29  1  0.489  0.249  0.011  1.0
  O  O30  1  0.511  0.751  0.989  1.0
  O  O31  1  0.523  0.245  0.669  1.0
  O  O32  1  0.486  0.260  0.327  1.0
  O  O33  1  0.750  0.508  0.829  1.0
  O  O34  1  0.750  0.529  0.492  1.0
  O  O35  1  0.750  0.007  0.814  1.0
  O  O36  1  0.750  0.028  0.517  1.0
  O  O37  1  0.750  0.509  0.182  1.0
  O  O38  1  0.750  0.996  0.162  1.0
  O  O39  1  0.014  0.260  0.327  1.0
  O  O40  1  0.977  0.245  0.669  1.0
  O  O41  1  0.989  0.751  0.989  1.0
[/CIF]
.
The material structure described by Fe8SiO12 crystallizes in the monoclinic P2_1/m space group. There are seven inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent O(1), two equivalent O(4), and two equivalent O(8) atoms to form FeO6 octahedra that share corners with two equivalent Fe(3)O4 tetrahedra, corners with two equivalent Fe(4)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, edges with two equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(5)O6 octahedra, and edges with two equivalent Fe(7)O6 octahedra. In the second Fe site, Fe(2) is bonded to one O(2), one O(3), one O(5), one O(9), and two equivalent O(6) atoms to form FeO6 octahedra that share corners with two equivalent Fe(2)O6 octahedra,  a cornercorner with one Fe(4)O4 tetrahedra,  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent Fe(3)O4 tetrahedra,  an edgeedge with one Fe(5)O6 octahedra,  an edgeedge with one Fe(7)O6 octahedra, edges with two equivalent Fe(6)O6 octahedra, and edges with three equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles are 15°. In the third Fe site, Fe(3) is bonded to one O(5), one O(9), and two equivalent O(1) atoms to form corner-sharing FeO4 tetrahedra. The corner-sharing octahedral tilt angles range from 54-59°. In the fourth Fe site, Fe(4) is bonded to one O(4), one O(7), and two equivalent O(2) atoms to form FeO4 tetrahedra that share  a cornercorner with one Fe(5)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra, corners with two equivalent Fe(7)O6 octahedra, corners with three equivalent Fe(6)O6 octahedra, and  a cornercorner with one Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 52-68°. In the fifth Fe site, Fe(5) is bonded to one O(4), one O(5), two equivalent O(1), and two equivalent O(3) atoms to form FeO6 octahedra that share  a cornercorner with one Fe(4)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, corners with three equivalent Fe(3)O4 tetrahedra,  an edgeedge with one Fe(6)O6 octahedra,  an edgeedge with one Fe(7)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, and edges with two equivalent Fe(2)O6 octahedra. In the sixth Fe site, Fe(6) is bonded to one O(6), one O(7), two equivalent O(2), and two equivalent O(3) atoms to form FeO6 octahedra that share corners with three equivalent Fe(4)O4 tetrahedra, corners with three equivalent Si(1)O4 tetrahedra,  an edgeedge with one Fe(5)O6 octahedra,  an edgeedge with one Fe(7)O6 octahedra, and edges with four equivalent Fe(2)O6 octahedra. In the seventh Fe site, Fe(7) is bonded to one O(8), one O(9), two equivalent O(1), and two equivalent O(2) atoms to form FeO6 octahedra that share  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent Fe(4)O4 tetrahedra, corners with three equivalent Fe(3)O4 tetrahedra,  an edgeedge with one Fe(5)O6 octahedra,  an edgeedge with one Fe(6)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, and edges with two equivalent Fe(2)O6 octahedra. Si(1) is bonded to one O(7), one O(8), and two equivalent O(3) atoms to form SiO4 tetrahedra that share  a cornercorner with one Fe(7)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra, corners with two equivalent Fe(5)O6 octahedra, corners with three equivalent Fe(6)O6 octahedra, and  a cornercorner with one Fe(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 46-57°. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Fe(1), one Fe(3), one Fe(5), and one Fe(7) atom. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Fe(2), one Fe(4), one Fe(6), and one Fe(7) atom. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to one Fe(2), one Fe(5), one Fe(6), and one Si(1) atom. In the fourth O site, O(4) is bonded in a rectangular see-saw-like geometry to one Fe(4), one Fe(5), and two equivalent Fe(1) atoms. In the fifth O site, O(5) is bonded in a rectangular see-saw-like geometry to one Fe(3), one Fe(5), and two equivalent Fe(2) atoms. In the sixth O site, O(6) is bonded to one Fe(6) and four equivalent Fe(2) atoms to form edge-sharing OFe5 square pyramids. In the seventh O site, O(7) is bonded in a trigonal planar geometry to one Fe(4), one Fe(6), and one Si(1) atom. In the eighth O site, O(8) is bonded in a distorted rectangular see-saw-like geometry to one Fe(7), two equivalent Fe(1), and one Si(1) atom. In the ninth O site, O(9) is bonded in a rectangular see-saw-like geometry to one Fe(3), one Fe(7), and two equivalent Fe(2) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Fe8SiO12
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.003
_cell_length_b   8.484
_cell_length_c   9.120
_cell_angle_alpha   89.285
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   464.451
_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  0.000  0.000  0.000  1.0
  Fe  Fe1  1  0.987  0.495  0.663  1.0
  Fe  Fe2  1  0.013  0.505  0.337  1.0
  Fe  Fe3  1  0.250  0.619  0.991  1.0
  Fe  Fe4  1  0.250  0.865  0.676  1.0
  Fe  Fe5  1  0.250  0.248  0.835  1.0
  Fe  Fe6  1  0.250  0.217  0.501  1.0
  Fe  Fe7  1  0.250  0.246  0.166  1.0
  Fe  Fe8  1  0.500  0.000  0.000  1.0
  Fe  Fe9  1  0.487  0.505  0.337  1.0
  Fe  Fe10  1  0.513  0.495  0.663  1.0
  Fe  Fe11  1  0.750  0.381  0.009  1.0
  Fe  Fe12  1  0.750  0.754  0.834  1.0
  Fe  Fe13  1  0.750  0.783  0.499  1.0
  Fe  Fe14  1  0.750  0.135  0.324  1.0
  Fe  Fe15  1  0.750  0.752  0.165  1.0
  Si  Si16  1  0.250  0.869  0.328  1.0
  Si  Si17  1  0.750  0.131  0.672  1.0
  O  O18  1  0.011  0.249  0.011  1.0
  O  O19  1  0.986  0.740  0.673  1.0
  O  O20  1  0.023  0.755  0.331  1.0
  O  O21  1  0.250  0.004  0.838  1.0
  O  O22  1  0.250  0.491  0.818  1.0
  O  O23  1  0.250  0.471  0.508  1.0
  O  O24  1  0.250  0.972  0.483  1.0
  O  O25  1  0.250  0.993  0.186  1.0
  O  O26  1  0.250  0.492  0.171  1.0
  O  O27  1  0.514  0.740  0.673  1.0
  O  O28  1  0.477  0.755  0.331  1.0
  O  O29  1  0.489  0.249  0.011  1.0
  O  O30  1  0.511  0.751  0.989  1.0
  O  O31  1  0.523  0.245  0.669  1.0
  O  O32  1  0.486  0.260  0.327  1.0
  O  O33  1  0.750  0.508  0.829  1.0
  O  O34  1  0.750  0.529  0.492  1.0
  O  O35  1  0.750  0.007  0.814  1.0
  O  O36  1  0.750  0.028  0.517  1.0
  O  O37  1  0.750  0.509  0.182  1.0
  O  O38  1  0.750  0.996  0.162  1.0
  O  O39  1  0.014  0.260  0.327  1.0
  O  O40  1  0.977  0.245  0.669  1.0
  O  O41  1  0.989  0.751  0.989  1.0
[/CIF]
.