The compound described by Fe2SiO4 is Spinel-like structured and crystallizes in the trigonal P3m1 space group. There are six inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(10) and three equivalent O(1) atoms to form FeO4 tetrahedra that share corners with three equivalent Fe(5)O6 octahedra, corners with three equivalent Si(3)O6 octahedra, and corners with six equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-62°. In the second Fe site, Fe(2) is bonded to one O(2), one O(5), two equivalent O(1), and two equivalent O(4) atoms to form FeO6 octahedra that share  a cornercorner with one Fe(3)O4 tetrahedra,  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent Fe(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra,  an edgeedge with one Si(3)O6 octahedra,  an edgeedge with one Si(6)O6 octahedra, and edges with four equivalent Fe(2)O6 octahedra. In the third Fe site, Fe(3) is bonded to one O(2) and three equivalent O(3) atoms to form FeO4 tetrahedra that share corners with three equivalent Fe(2)O6 octahedra, corners with three equivalent Si(6)O6 octahedra, and corners with six equivalent Fe(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-61°. In the fourth Fe site, Fe(4) is bonded to one O(6), one O(9), two equivalent O(3), and two equivalent O(7) atoms to form FeO6 octahedra that share  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(5)O4 tetrahedra, corners with two equivalent Fe(3)O4 tetrahedra, corners with two equivalent Si(4)O4 tetrahedra,  an edgeedge with one Fe(6)O6 octahedra,  an edgeedge with one Si(6)O6 octahedra, and edges with four equivalent Fe(4)O6 octahedra. In the fifth Fe site, Fe(5) is bonded to one O(10), one O(12), two equivalent O(11), and two equivalent O(8) atoms to form FeO6 octahedra that share  a cornercorner with one Fe(1)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(5)O4 tetrahedra,  an edgeedge with one Fe(6)O6 octahedra,  an edgeedge with one Si(3)O6 octahedra, and edges with four equivalent Fe(5)O6 octahedra. In the sixth Fe site, Fe(6) is bonded to three equivalent O(7) and three equivalent O(8) atoms to form FeO6 octahedra that share corners with three equivalent Si(4)O4 tetrahedra, corners with three equivalent Si(5)O4 tetrahedra, edges with three equivalent Fe(4)O6 octahedra, and edges with three equivalent Fe(5)O6 octahedra. There are six inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(5) and three equivalent O(11) atoms to form SiO4 tetrahedra that share corners with three equivalent Fe(2)O6 octahedra, corners with three equivalent Si(3)O6 octahedra, and corners with six equivalent Fe(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 52-54°. In the second Si site, Si(2) is bonded to one O(9) and three equivalent O(4) atoms to form SiO4 tetrahedra that share corners with three equivalent Fe(4)O6 octahedra, corners with three equivalent Si(6)O6 octahedra, and corners with six equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-55°. In the third Si site, Si(3) is bonded to three equivalent O(1) and three equivalent O(11) atoms to form SiO6 octahedra that share corners with three equivalent Fe(1)O4 tetrahedra, corners with three equivalent Si(1)O4 tetrahedra, edges with three equivalent Fe(2)O6 octahedra, and edges with three equivalent Fe(5)O6 octahedra. In the fourth Si site, Si(4) is bonded to one O(12) and three equivalent O(7) atoms to form SiO4 tetrahedra that share corners with three equivalent Fe(5)O6 octahedra, corners with three equivalent Fe(6)O6 octahedra, and corners with six equivalent Fe(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 52-54°. In the fifth Si site, Si(5) is bonded to one O(6) and three equivalent O(8) atoms to form SiO4 tetrahedra that share corners with three equivalent Fe(4)O6 octahedra, corners with three equivalent Fe(6)O6 octahedra, and corners with six equivalent Fe(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-52°. In the sixth Si site, Si(6) is bonded to three equivalent O(3) and three equivalent O(4) atoms to form SiO6 octahedra that share corners with three equivalent Fe(3)O4 tetrahedra, corners with three equivalent Si(2)O4 tetrahedra, edges with three equivalent Fe(2)O6 octahedra, and edges with three equivalent Fe(4)O6 octahedra. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to one Fe(1), two equivalent Fe(2), and one Si(3) atom. In the second O site, O(2) is bonded in a distorted trigonal pyramidal geometry to one Fe(3) and three equivalent Fe(2) atoms. In the third O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to one Fe(3), two equivalent Fe(4), and one Si(6) atom. In the fourth O site, O(4) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Fe(2), one Si(2), and one Si(6) atom. In the fifth O site, O(5) is bonded in a rectangular see-saw-like geometry to three equivalent Fe(2) and one Si(1) atom. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to three equivalent Fe(4) and one Si(5) atom. In the seventh O site, O(7) is bonded in a rectangular see-saw-like geometry to one Fe(6), two equivalent Fe(4), and one Si(4) atom. In the eighth O site, O(8) is bonded in a distorted rectangular see-saw-like geometry to one Fe(6), two equivalent Fe(5), and one Si(5) atom. In the ninth O site, O(9) is bonded in a distorted rectangular see-saw-like geometry to three equivalent Fe(4) and one Si(2) atom. In the tenth O site, O(10) is bonded in a distorted trigonal pyramidal geometry to one Fe(1) and three equivalent Fe(5) atoms. In the eleventh O site, O(11) is bonded in a rectangular see-saw-like geometry to two equivalent Fe(5), one Si(1), and one Si(3) atom. In the twelfth O site, O(12) is bonded in a rectangular see-saw-like geometry to three equivalent Fe(5) and one Si(4) atom. is represented by the CIF file [CIF]
data_Fe2SiO4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.886
_cell_length_b   5.886
_cell_length_c   14.897
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   446.897
_cell_formula_units_Z   6
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  0.667  0.333  0.927  1.0
  Fe  Fe1  1  0.166  0.834  0.793  1.0
  Fe  Fe2  1  0.333  0.667  0.592  1.0
  Fe  Fe3  1  0.669  0.834  0.793  1.0
  Fe  Fe4  1  0.166  0.331  0.793  1.0
  Fe  Fe5  1  0.834  0.166  0.452  1.0
  Fe  Fe6  1  0.331  0.166  0.452  1.0
  Fe  Fe7  1  0.499  0.501  0.129  1.0
  Fe  Fe8  1  0.834  0.669  0.452  1.0
  Fe  Fe9  1  0.667  0.333  0.288  1.0
  Fe  Fe10  1  0.002  0.501  0.129  1.0
  Fe  Fe11  1  0.499  0.998  0.129  1.0
  Si  Si12  1  0.000  0.000  0.996  1.0
  Si  Si13  1  0.667  0.333  0.656  1.0
  Si  Si14  1  0.333  0.667  0.945  1.0
  Si  Si15  1  0.333  0.667  0.331  1.0
  Si  Si16  1  0.000  0.000  0.251  1.0
  Si  Si17  1  0.000  0.000  0.608  1.0
  O  O18  1  0.478  0.957  0.889  1.0
  O  O19  1  0.043  0.522  0.889  1.0
  O  O20  1  0.333  0.667  0.723  1.0
  O  O21  1  0.143  0.286  0.547  1.0
  O  O22  1  0.829  0.171  0.694  1.0
  O  O23  1  0.478  0.522  0.889  1.0
  O  O24  1  0.343  0.171  0.694  1.0
  O  O25  1  0.000  0.000  0.883  1.0
  O  O26  1  0.714  0.857  0.547  1.0
  O  O27  1  0.000  0.000  0.362  1.0
  O  O28  1  0.487  0.513  0.370  1.0
  O  O29  1  0.846  0.693  0.214  1.0
  O  O30  1  0.143  0.857  0.547  1.0
  O  O31  1  0.829  0.657  0.694  1.0
  O  O32  1  0.667  0.333  0.545  1.0
  O  O33  1  0.026  0.513  0.370  1.0
  O  O34  1  0.307  0.154  0.214  1.0
  O  O35  1  0.667  0.333  0.061  1.0
  O  O36  1  0.160  0.840  0.032  1.0
  O  O37  1  0.846  0.154  0.214  1.0
  O  O38  1  0.487  0.974  0.370  1.0
  O  O39  1  0.333  0.667  0.218  1.0
  O  O40  1  0.679  0.840  0.032  1.0
  O  O41  1  0.160  0.321  0.032  1.0
[/CIF]
.
The compound described by Fe2SiO4 is Spinel-like structured and crystallizes in the trigonal P3m1 space group. There are six inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(10) and three equivalent O(1) atoms to form FeO4 tetrahedra that share corners with three equivalent Fe(5)O6 octahedra, corners with three equivalent Si(3)O6 octahedra, and corners with six equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-62°. In the second Fe site, Fe(2) is bonded to one O(2), one O(5), two equivalent O(1), and two equivalent O(4) atoms to form FeO6 octahedra that share  a cornercorner with one Fe(3)O4 tetrahedra,  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent Fe(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra,  an edgeedge with one Si(3)O6 octahedra,  an edgeedge with one Si(6)O6 octahedra, and edges with four equivalent Fe(2)O6 octahedra. In the third Fe site, Fe(3) is bonded to one O(2) and three equivalent O(3) atoms to form FeO4 tetrahedra that share corners with three equivalent Fe(2)O6 octahedra, corners with three equivalent Si(6)O6 octahedra, and corners with six equivalent Fe(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-61°. In the fourth Fe site, Fe(4) is bonded to one O(6), one O(9), two equivalent O(3), and two equivalent O(7) atoms to form FeO6 octahedra that share  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(5)O4 tetrahedra, corners with two equivalent Fe(3)O4 tetrahedra, corners with two equivalent Si(4)O4 tetrahedra,  an edgeedge with one Fe(6)O6 octahedra,  an edgeedge with one Si(6)O6 octahedra, and edges with four equivalent Fe(4)O6 octahedra. In the fifth Fe site, Fe(5) is bonded to one O(10), one O(12), two equivalent O(11), and two equivalent O(8) atoms to form FeO6 octahedra that share  a cornercorner with one Fe(1)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(5)O4 tetrahedra,  an edgeedge with one Fe(6)O6 octahedra,  an edgeedge with one Si(3)O6 octahedra, and edges with four equivalent Fe(5)O6 octahedra. In the sixth Fe site, Fe(6) is bonded to three equivalent O(7) and three equivalent O(8) atoms to form FeO6 octahedra that share corners with three equivalent Si(4)O4 tetrahedra, corners with three equivalent Si(5)O4 tetrahedra, edges with three equivalent Fe(4)O6 octahedra, and edges with three equivalent Fe(5)O6 octahedra. There are six inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(5) and three equivalent O(11) atoms to form SiO4 tetrahedra that share corners with three equivalent Fe(2)O6 octahedra, corners with three equivalent Si(3)O6 octahedra, and corners with six equivalent Fe(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 52-54°. In the second Si site, Si(2) is bonded to one O(9) and three equivalent O(4) atoms to form SiO4 tetrahedra that share corners with three equivalent Fe(4)O6 octahedra, corners with three equivalent Si(6)O6 octahedra, and corners with six equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-55°. In the third Si site, Si(3) is bonded to three equivalent O(1) and three equivalent O(11) atoms to form SiO6 octahedra that share corners with three equivalent Fe(1)O4 tetrahedra, corners with three equivalent Si(1)O4 tetrahedra, edges with three equivalent Fe(2)O6 octahedra, and edges with three equivalent Fe(5)O6 octahedra. In the fourth Si site, Si(4) is bonded to one O(12) and three equivalent O(7) atoms to form SiO4 tetrahedra that share corners with three equivalent Fe(5)O6 octahedra, corners with three equivalent Fe(6)O6 octahedra, and corners with six equivalent Fe(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 52-54°. In the fifth Si site, Si(5) is bonded to one O(6) and three equivalent O(8) atoms to form SiO4 tetrahedra that share corners with three equivalent Fe(4)O6 octahedra, corners with three equivalent Fe(6)O6 octahedra, and corners with six equivalent Fe(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-52°. In the sixth Si site, Si(6) is bonded to three equivalent O(3) and three equivalent O(4) atoms to form SiO6 octahedra that share corners with three equivalent Fe(3)O4 tetrahedra, corners with three equivalent Si(2)O4 tetrahedra, edges with three equivalent Fe(2)O6 octahedra, and edges with three equivalent Fe(4)O6 octahedra. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to one Fe(1), two equivalent Fe(2), and one Si(3) atom. In the second O site, O(2) is bonded in a distorted trigonal pyramidal geometry to one Fe(3) and three equivalent Fe(2) atoms. In the third O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to one Fe(3), two equivalent Fe(4), and one Si(6) atom. In the fourth O site, O(4) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Fe(2), one Si(2), and one Si(6) atom. In the fifth O site, O(5) is bonded in a rectangular see-saw-like geometry to three equivalent Fe(2) and one Si(1) atom. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to three equivalent Fe(4) and one Si(5) atom. In the seventh O site, O(7) is bonded in a rectangular see-saw-like geometry to one Fe(6), two equivalent Fe(4), and one Si(4) atom. In the eighth O site, O(8) is bonded in a distorted rectangular see-saw-like geometry to one Fe(6), two equivalent Fe(5), and one Si(5) atom. In the ninth O site, O(9) is bonded in a distorted rectangular see-saw-like geometry to three equivalent Fe(4) and one Si(2) atom. In the tenth O site, O(10) is bonded in a distorted trigonal pyramidal geometry to one Fe(1) and three equivalent Fe(5) atoms. In the eleventh O site, O(11) is bonded in a rectangular see-saw-like geometry to two equivalent Fe(5), one Si(1), and one Si(3) atom. In the twelfth O site, O(12) is bonded in a rectangular see-saw-like geometry to three equivalent Fe(5) and one Si(4) atom. is represented by the CIF file [CIF]
data_Fe2SiO4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.886
_cell_length_b   5.886
_cell_length_c   14.897
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   446.897
_cell_formula_units_Z   6
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  0.667  0.333  0.927  1.0
  Fe  Fe1  1  0.166  0.834  0.793  1.0
  Fe  Fe2  1  0.333  0.667  0.592  1.0
  Fe  Fe3  1  0.669  0.834  0.793  1.0
  Fe  Fe4  1  0.166  0.331  0.793  1.0
  Fe  Fe5  1  0.834  0.166  0.452  1.0
  Fe  Fe6  1  0.331  0.166  0.452  1.0
  Fe  Fe7  1  0.499  0.501  0.129  1.0
  Fe  Fe8  1  0.834  0.669  0.452  1.0
  Fe  Fe9  1  0.667  0.333  0.288  1.0
  Fe  Fe10  1  0.002  0.501  0.129  1.0
  Fe  Fe11  1  0.499  0.998  0.129  1.0
  Si  Si12  1  0.000  0.000  0.996  1.0
  Si  Si13  1  0.667  0.333  0.656  1.0
  Si  Si14  1  0.333  0.667  0.945  1.0
  Si  Si15  1  0.333  0.667  0.331  1.0
  Si  Si16  1  0.000  0.000  0.251  1.0
  Si  Si17  1  0.000  0.000  0.608  1.0
  O  O18  1  0.478  0.957  0.889  1.0
  O  O19  1  0.043  0.522  0.889  1.0
  O  O20  1  0.333  0.667  0.723  1.0
  O  O21  1  0.143  0.286  0.547  1.0
  O  O22  1  0.829  0.171  0.694  1.0
  O  O23  1  0.478  0.522  0.889  1.0
  O  O24  1  0.343  0.171  0.694  1.0
  O  O25  1  0.000  0.000  0.883  1.0
  O  O26  1  0.714  0.857  0.547  1.0
  O  O27  1  0.000  0.000  0.362  1.0
  O  O28  1  0.487  0.513  0.370  1.0
  O  O29  1  0.846  0.693  0.214  1.0
  O  O30  1  0.143  0.857  0.547  1.0
  O  O31  1  0.829  0.657  0.694  1.0
  O  O32  1  0.667  0.333  0.545  1.0
  O  O33  1  0.026  0.513  0.370  1.0
  O  O34  1  0.307  0.154  0.214  1.0
  O  O35  1  0.667  0.333  0.061  1.0
  O  O36  1  0.160  0.840  0.032  1.0
  O  O37  1  0.846  0.154  0.214  1.0
  O  O38  1  0.487  0.974  0.370  1.0
  O  O39  1  0.333  0.667  0.218  1.0
  O  O40  1  0.679  0.840  0.032  1.0
  O  O41  1  0.160  0.321  0.032  1.0
[/CIF]
.