The compound described by Mg7Fe(SiO4)4 is Spinel-derived structured and crystallizes in the triclinic P-1 space group. There are five inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(6) atoms to form MgO6 octahedra that share corners with four equivalent Mg(5)O6 octahedra, corners with two equivalent Si(2)O4 tetrahedra, edges with two equivalent Mg(2)O6 octahedra, edges with two equivalent Mg(3)O6 octahedra, and edges with two equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 55-63°. In the second Mg site, Mg(2) is bonded to one O(1), one O(2), one O(3), one O(4), one O(7), and one O(8) atom to form MgO6 octahedra that share corners with two equivalent Mg(4)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, corners with four equivalent Mg(5)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, corners with three equivalent Si(1)O4 tetrahedra,  an edgeedge with one Mg(1)O6 octahedra,  an edgeedge with one Mg(3)O6 octahedra, and  an edgeedge with one Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 50-64°. In the third Mg site, Mg(3) is bonded to two equivalent O(1), two equivalent O(4), and two equivalent O(6) atoms to form MgO6 octahedra that share corners with four equivalent Mg(5)O6 octahedra, corners with two equivalent Si(2)O4 tetrahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Mg(2)O6 octahedra, and edges with two equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 56-63°. In the fourth Mg site, Mg(4) is bonded to two equivalent O(2), two equivalent O(5), and two equivalent O(7) atoms to form MgO6 octahedra that share corners with four equivalent Mg(2)O6 octahedra, corners with two equivalent Si(1)O4 tetrahedra, edges with two equivalent Mg(5)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, and edges with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 55-62°. In the fifth Mg site, Mg(5) is bonded to one O(3), one O(4), one O(5), one O(6), one O(7), and one O(8) atom to form MgO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Mg(3)O6 octahedra, corners with four equivalent Mg(2)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra, corners with three equivalent Si(2)O4 tetrahedra,  an edgeedge with one Mg(4)O6 octahedra,  an edgeedge with one Fe(1)O6 octahedra, and  an edgeedge with one Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 50-63°. Fe(1) is bonded to two equivalent O(2), two equivalent O(5), and two equivalent O(8) atoms to form FeO6 octahedra that share corners with four equivalent Mg(2)O6 octahedra, corners with two equivalent Si(1)O4 tetrahedra, edges with two equivalent Mg(4)O6 octahedra, edges with two equivalent Mg(5)O6 octahedra, and edges with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 56-64°. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(5), one O(7), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Mg(4)O6 octahedra,  a cornercorner with one Mg(5)O6 octahedra,  a cornercorner with one Fe(1)O6 octahedra, corners with three equivalent Mg(2)O6 octahedra,  an edgeedge with one Mg(4)O6 octahedra,  an edgeedge with one Mg(5)O6 octahedra, and  an edgeedge with one Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 53-61°. In the second Si site, Si(2) is bonded to one O(1), one O(3), one O(4), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra,  a cornercorner with one Mg(2)O6 octahedra,  a cornercorner with one Mg(3)O6 octahedra, corners with three equivalent Mg(5)O6 octahedra,  an edgeedge with one Mg(1)O6 octahedra,  an edgeedge with one Mg(2)O6 octahedra, and  an edgeedge with one Mg(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 56-61°. There are eight inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Mg(2), one Mg(3), and one Si(2) atom to form distorted corner-sharing OMg3Si trigonal pyramids. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mg(2), one Mg(4), one Fe(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(1), one Mg(2), one Mg(5), and one Si(2) atom. In the fourth O site, O(4) is bonded in a rectangular see-saw-like geometry to one Mg(2), one Mg(3), one Mg(5), and one Si(2) atom. In the fifth O site, O(5) is bonded to one Mg(4), one Mg(5), one Fe(1), and one Si(1) atom to form distorted corner-sharing OMg2FeSi trigonal pyramids. In the sixth O site, O(6) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Mg(3), one Mg(5), and one Si(2) atom. In the seventh O site, O(7) is bonded in a rectangular see-saw-like geometry to one Mg(2), one Mg(4), one Mg(5), and one Si(1) atom. In the eighth O site, O(8) is bonded in a rectangular see-saw-like geometry to one Mg(2), one Mg(5), one Fe(1), and one Si(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Mg7Fe(SiO4)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.822
_cell_length_b   6.062
_cell_length_c   10.354
_cell_angle_alpha   89.701
_cell_angle_beta   89.917
_cell_angle_gamma   89.780
_symmetry_Int_Tables_number   1
_cell_volume   302.634
_cell_formula_units_Z   1
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  0.000  0.000  0.000  1.0
  Mg  Mg1  1  0.989  0.245  0.724  1.0
  Mg  Mg2  1  0.011  0.755  0.276  1.0
  Mg  Mg3  1  0.000  0.500  0.000  1.0
  Mg  Mg4  1  0.500  0.000  0.500  1.0
  Mg  Mg5  1  0.510  0.251  0.222  1.0
  Mg  Mg6  1  0.490  0.749  0.778  1.0
  Fe  Fe7  1  0.500  0.500  0.500  1.0
  Si  Si8  1  0.926  0.751  0.594  1.0
  Si  Si9  1  0.425  0.249  0.907  1.0
  Si  Si10  1  0.575  0.751  0.093  1.0
  Si  Si11  1  0.074  0.249  0.406  1.0
  O  O12  1  0.765  0.249  0.908  1.0
  O  O13  1  0.213  0.245  0.554  1.0
  O  O14  1  0.276  0.033  0.838  1.0
  O  O15  1  0.235  0.751  0.092  1.0
  O  O16  1  0.787  0.755  0.446  1.0
  O  O17  1  0.724  0.967  0.162  1.0
  O  O18  1  0.723  0.534  0.163  1.0
  O  O19  1  0.277  0.466  0.837  1.0
  O  O20  1  0.735  0.246  0.406  1.0
  O  O21  1  0.277  0.249  0.053  1.0
  O  O22  1  0.229  0.034  0.337  1.0
  O  O23  1  0.265  0.754  0.594  1.0
  O  O24  1  0.723  0.751  0.947  1.0
  O  O25  1  0.771  0.966  0.663  1.0
  O  O26  1  0.786  0.534  0.666  1.0
  O  O27  1  0.214  0.466  0.334  1.0
[/CIF]
.
The compound described by Mg7Fe(SiO4)4 is Spinel-derived structured and crystallizes in the triclinic P-1 space group. There are five inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(6) atoms to form MgO6 octahedra that share corners with four equivalent Mg(5)O6 octahedra, corners with two equivalent Si(2)O4 tetrahedra, edges with two equivalent Mg(2)O6 octahedra, edges with two equivalent Mg(3)O6 octahedra, and edges with two equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 55-63°. In the second Mg site, Mg(2) is bonded to one O(1), one O(2), one O(3), one O(4), one O(7), and one O(8) atom to form MgO6 octahedra that share corners with two equivalent Mg(4)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, corners with four equivalent Mg(5)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, corners with three equivalent Si(1)O4 tetrahedra,  an edgeedge with one Mg(1)O6 octahedra,  an edgeedge with one Mg(3)O6 octahedra, and  an edgeedge with one Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 50-64°. In the third Mg site, Mg(3) is bonded to two equivalent O(1), two equivalent O(4), and two equivalent O(6) atoms to form MgO6 octahedra that share corners with four equivalent Mg(5)O6 octahedra, corners with two equivalent Si(2)O4 tetrahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Mg(2)O6 octahedra, and edges with two equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 56-63°. In the fourth Mg site, Mg(4) is bonded to two equivalent O(2), two equivalent O(5), and two equivalent O(7) atoms to form MgO6 octahedra that share corners with four equivalent Mg(2)O6 octahedra, corners with two equivalent Si(1)O4 tetrahedra, edges with two equivalent Mg(5)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, and edges with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 55-62°. In the fifth Mg site, Mg(5) is bonded to one O(3), one O(4), one O(5), one O(6), one O(7), and one O(8) atom to form MgO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Mg(3)O6 octahedra, corners with four equivalent Mg(2)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra, corners with three equivalent Si(2)O4 tetrahedra,  an edgeedge with one Mg(4)O6 octahedra,  an edgeedge with one Fe(1)O6 octahedra, and  an edgeedge with one Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 50-63°. Fe(1) is bonded to two equivalent O(2), two equivalent O(5), and two equivalent O(8) atoms to form FeO6 octahedra that share corners with four equivalent Mg(2)O6 octahedra, corners with two equivalent Si(1)O4 tetrahedra, edges with two equivalent Mg(4)O6 octahedra, edges with two equivalent Mg(5)O6 octahedra, and edges with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 56-64°. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(5), one O(7), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Mg(4)O6 octahedra,  a cornercorner with one Mg(5)O6 octahedra,  a cornercorner with one Fe(1)O6 octahedra, corners with three equivalent Mg(2)O6 octahedra,  an edgeedge with one Mg(4)O6 octahedra,  an edgeedge with one Mg(5)O6 octahedra, and  an edgeedge with one Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 53-61°. In the second Si site, Si(2) is bonded to one O(1), one O(3), one O(4), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra,  a cornercorner with one Mg(2)O6 octahedra,  a cornercorner with one Mg(3)O6 octahedra, corners with three equivalent Mg(5)O6 octahedra,  an edgeedge with one Mg(1)O6 octahedra,  an edgeedge with one Mg(2)O6 octahedra, and  an edgeedge with one Mg(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 56-61°. There are eight inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Mg(2), one Mg(3), and one Si(2) atom to form distorted corner-sharing OMg3Si trigonal pyramids. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mg(2), one Mg(4), one Fe(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(1), one Mg(2), one Mg(5), and one Si(2) atom. In the fourth O site, O(4) is bonded in a rectangular see-saw-like geometry to one Mg(2), one Mg(3), one Mg(5), and one Si(2) atom. In the fifth O site, O(5) is bonded to one Mg(4), one Mg(5), one Fe(1), and one Si(1) atom to form distorted corner-sharing OMg2FeSi trigonal pyramids. In the sixth O site, O(6) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Mg(3), one Mg(5), and one Si(2) atom. In the seventh O site, O(7) is bonded in a rectangular see-saw-like geometry to one Mg(2), one Mg(4), one Mg(5), and one Si(1) atom. In the eighth O site, O(8) is bonded in a rectangular see-saw-like geometry to one Mg(2), one Mg(5), one Fe(1), and one Si(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Mg7Fe(SiO4)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.822
_cell_length_b   6.062
_cell_length_c   10.354
_cell_angle_alpha   89.701
_cell_angle_beta   89.917
_cell_angle_gamma   89.780
_symmetry_Int_Tables_number   1
_cell_volume   302.634
_cell_formula_units_Z   1
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  0.000  0.000  0.000  1.0
  Mg  Mg1  1  0.989  0.245  0.724  1.0
  Mg  Mg2  1  0.011  0.755  0.276  1.0
  Mg  Mg3  1  0.000  0.500  0.000  1.0
  Mg  Mg4  1  0.500  0.000  0.500  1.0
  Mg  Mg5  1  0.510  0.251  0.222  1.0
  Mg  Mg6  1  0.490  0.749  0.778  1.0
  Fe  Fe7  1  0.500  0.500  0.500  1.0
  Si  Si8  1  0.926  0.751  0.594  1.0
  Si  Si9  1  0.425  0.249  0.907  1.0
  Si  Si10  1  0.575  0.751  0.093  1.0
  Si  Si11  1  0.074  0.249  0.406  1.0
  O  O12  1  0.765  0.249  0.908  1.0
  O  O13  1  0.213  0.245  0.554  1.0
  O  O14  1  0.276  0.033  0.838  1.0
  O  O15  1  0.235  0.751  0.092  1.0
  O  O16  1  0.787  0.755  0.446  1.0
  O  O17  1  0.724  0.967  0.162  1.0
  O  O18  1  0.723  0.534  0.163  1.0
  O  O19  1  0.277  0.466  0.837  1.0
  O  O20  1  0.735  0.246  0.406  1.0
  O  O21  1  0.277  0.249  0.053  1.0
  O  O22  1  0.229  0.034  0.337  1.0
  O  O23  1  0.265  0.754  0.594  1.0
  O  O24  1  0.723  0.751  0.947  1.0
  O  O25  1  0.771  0.966  0.663  1.0
  O  O26  1  0.786  0.534  0.666  1.0
  O  O27  1  0.214  0.466  0.334  1.0
[/CIF]
.