The compound described by MgFe4Sn7Si2O16 is Esseneite-derived structured and crystallizes in the triclinic P-1 space group. Mg(1) is bonded in a 4-coordinate geometry to two equivalent O(3) and two equivalent O(4) atoms. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent O(5), two equivalent O(7), and two equivalent O(8) atoms to form distorted FeO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, edges with two equivalent Fe(3)O6 octahedra, edges with two equivalent Fe(4)O6 octahedra, and edges with two equivalent Sn(2)O6 octahedra. In the second Fe site, Fe(2) is bonded to two equivalent Sn(1), two equivalent Sn(3), and two equivalent Sn(4) atoms to form distorted FeSn6 octahedra that share corners with two equivalent O(5)Fe2Sn2 tetrahedra, corners with two equivalent O(6)Fe2Sn2 tetrahedra, corners with two equivalent O(8)Fe2Sn2 tetrahedra, and corners with six equivalent O(3)MgSn3 tetrahedra. In the third Fe site, Fe(3) is bonded to two equivalent O(5), two equivalent O(6), and two equivalent O(7) atoms to form distorted FeO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, edges with two equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(4)O6 octahedra, and edges with two equivalent Sn(2)O6 octahedra. In the fourth Fe site, Fe(4) is bonded to two equivalent O(6), two equivalent O(7), and two equivalent O(8) atoms to form distorted FeO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, edges with two equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(3)O6 octahedra, and edges with two equivalent Sn(2)O6 octahedra. There are four inequivalent Sn sites. In the first Sn site, Sn(1) is bonded in a 3-coordinate geometry to one Fe(2), one O(2), one O(3), and one O(6) atom. In the second Sn site, Sn(2) is bonded to two equivalent O(5), two equivalent O(6), and two equivalent O(8) atoms to form SnO6 octahedra that share edges with two equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(3)O6 octahedra, and edges with two equivalent Fe(4)O6 octahedra. In the third Sn site, Sn(3) is bonded in a 3-coordinate geometry to one Fe(2), one O(1), one O(3), and one O(5) atom. In the fourth Sn site, Sn(4) is bonded in a 4-coordinate geometry to one Fe(2), one O(1), one O(2), one O(3), and one O(8) atom. Si(1) is bonded to one O(1), one O(2), one O(4), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(3)O6 octahedra, and  a cornercorner with one Fe(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 65-70°. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Sn(3), one Sn(4), and one Si(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Sn(1), one Sn(4), and one Si(1) atom. In the third O site, O(3) is bonded to one Mg(1), one Sn(1), one Sn(3), and one Sn(4) atom to form distorted OMgSn3 tetrahedra that share corners with three equivalent Fe(2)Sn6 octahedra,  a cornercorner with one O(5)Fe2Sn2 tetrahedra,  a cornercorner with one O(6)Fe2Sn2 tetrahedra,  a cornercorner with one O(8)Fe2Sn2 tetrahedra, and  a cornercorner with one O(3)MgSn3 tetrahedra. The corner-sharing octahedral tilt angles range from 50-60°. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to one Mg(1) and one Si(1) atom. In the fifth O site, O(5) is bonded to one Fe(1), one Fe(3), one Sn(2), and one Sn(3) atom to form OFe2Sn2 tetrahedra that share  a cornercorner with one Fe(2)Sn6 octahedra,  a cornercorner with one O(3)MgSn3 tetrahedra, corners with two equivalent O(6)Fe2Sn2 tetrahedra, corners with two equivalent O(8)Fe2Sn2 tetrahedra, corners with two equivalent O(7)Fe3Si tetrahedra, corners with three equivalent O(5)Fe2Sn2 tetrahedra,  an edgeedge with one O(6)Fe2Sn2 tetrahedra,  an edgeedge with one O(8)Fe2Sn2 tetrahedra, and  an edgeedge with one O(7)Fe3Si tetrahedra. The corner-sharing octahedral tilt angles are 46°. In the sixth O site, O(6) is bonded to one Fe(3), one Fe(4), one Sn(1), and one Sn(2) atom to form OFe2Sn2 tetrahedra that share  a cornercorner with one Fe(2)Sn6 octahedra,  a cornercorner with one O(3)MgSn3 tetrahedra, corners with two equivalent O(5)Fe2Sn2 tetrahedra, corners with two equivalent O(8)Fe2Sn2 tetrahedra, corners with two equivalent O(7)Fe3Si tetrahedra, corners with three equivalent O(6)Fe2Sn2 tetrahedra,  an edgeedge with one O(5)Fe2Sn2 tetrahedra,  an edgeedge with one O(8)Fe2Sn2 tetrahedra, and  an edgeedge with one O(7)Fe3Si tetrahedra. The corner-sharing octahedral tilt angles are 47°. In the seventh O site, O(7) is bonded to one Fe(1), one Fe(3), one Fe(4), and one Si(1) atom to form OFe3Si tetrahedra that share corners with two equivalent O(5)Fe2Sn2 tetrahedra, corners with two equivalent O(6)Fe2Sn2 tetrahedra, corners with two equivalent O(8)Fe2Sn2 tetrahedra, corners with three equivalent O(7)Fe3Si tetrahedra,  an edgeedge with one O(5)Fe2Sn2 tetrahedra,  an edgeedge with one O(6)Fe2Sn2 tetrahedra, and  an edgeedge with one O(8)Fe2Sn2 tetrahedra. In the eighth O site, O(8) is bonded to one Fe(1), one Fe(4), one Sn(2), and one Sn(4) atom to form distorted OFe2Sn2 tetrahedra that share  a cornercorner with one Fe(2)Sn6 octahedra,  a cornercorner with one O(3)MgSn3 tetrahedra, corners with two equivalent O(5)Fe2Sn2 tetrahedra, corners with two equivalent O(6)Fe2Sn2 tetrahedra, corners with two equivalent O(7)Fe3Si tetrahedra, corners with three equivalent O(8)Fe2Sn2 tetrahedra,  an edgeedge with one O(5)Fe2Sn2 tetrahedra,  an edgeedge with one O(6)Fe2Sn2 tetrahedra, and  an edgeedge with one O(7)Fe3Si tetrahedra. The corner-sharing octahedral tilt angles are 55°. is represented by the CIF file [CIF]
data_MgFe4Si2Sn7O16
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.038
_cell_length_b   7.031
_cell_length_c   10.028
_cell_angle_alpha   89.899
_cell_angle_beta   90.147
_cell_angle_gamma   119.824
_symmetry_Int_Tables_number   1
_cell_volume   430.487
_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  0.500  0.000  1.0
  Fe  Fe1  1  0.500  1.000  0.500  1.0
  Fe  Fe2  1  0.000  0.000  0.000  1.0
  Fe  Fe3  1  0.000  0.500  0.500  1.0
  Fe  Fe4  1  0.500  0.500  0.500  1.0
  Si  Si5  1  0.338  0.668  0.254  1.0
  Si  Si6  1  0.662  0.332  0.746  1.0
  Sn  Sn7  1  0.181  0.319  0.809  1.0
  Sn  Sn8  1  1.000  1.000  0.500  1.0
  Sn  Sn9  1  0.180  0.862  0.808  1.0
  Sn  Sn10  1  0.662  0.831  0.824  1.0
  Sn  Sn11  1  0.338  0.169  0.176  1.0
  Sn  Sn12  1  0.820  0.138  0.192  1.0
  Sn  Sn13  1  0.819  0.681  0.191  1.0
  O  O14  1  0.470  0.928  0.210  1.0
  O  O15  1  0.468  0.541  0.207  1.0
  O  O16  1  0.314  0.657  0.860  1.0
  O  O17  1  0.530  0.072  0.790  1.0
  O  O18  1  0.096  0.549  0.187  1.0
  O  O19  1  0.842  0.157  0.400  1.0
  O  O20  1  0.904  0.451  0.813  1.0
  O  O21  1  0.160  0.314  0.600  1.0
  O  O22  1  0.532  0.460  0.793  1.0
  O  O23  1  0.675  0.340  0.581  1.0
  O  O24  1  0.840  0.686  0.400  1.0
  O  O25  1  0.686  0.343  0.140  1.0
  O  O26  1  0.307  0.151  0.391  1.0
  O  O27  1  0.325  0.660  0.419  1.0
  O  O28  1  0.158  0.843  0.600  1.0
  O  O29  1  0.693  0.849  0.609  1.0
[/CIF]
.
The compound described by MgFe4Sn7Si2O16 is Esseneite-derived structured and crystallizes in the triclinic P-1 space group. Mg(1) is bonded in a 4-coordinate geometry to two equivalent O(3) and two equivalent O(4) atoms. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent O(5), two equivalent O(7), and two equivalent O(8) atoms to form distorted FeO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, edges with two equivalent Fe(3)O6 octahedra, edges with two equivalent Fe(4)O6 octahedra, and edges with two equivalent Sn(2)O6 octahedra. In the second Fe site, Fe(2) is bonded to two equivalent Sn(1), two equivalent Sn(3), and two equivalent Sn(4) atoms to form distorted FeSn6 octahedra that share corners with two equivalent O(5)Fe2Sn2 tetrahedra, corners with two equivalent O(6)Fe2Sn2 tetrahedra, corners with two equivalent O(8)Fe2Sn2 tetrahedra, and corners with six equivalent O(3)MgSn3 tetrahedra. In the third Fe site, Fe(3) is bonded to two equivalent O(5), two equivalent O(6), and two equivalent O(7) atoms to form distorted FeO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, edges with two equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(4)O6 octahedra, and edges with two equivalent Sn(2)O6 octahedra. In the fourth Fe site, Fe(4) is bonded to two equivalent O(6), two equivalent O(7), and two equivalent O(8) atoms to form distorted FeO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, edges with two equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(3)O6 octahedra, and edges with two equivalent Sn(2)O6 octahedra. There are four inequivalent Sn sites. In the first Sn site, Sn(1) is bonded in a 3-coordinate geometry to one Fe(2), one O(2), one O(3), and one O(6) atom. In the second Sn site, Sn(2) is bonded to two equivalent O(5), two equivalent O(6), and two equivalent O(8) atoms to form SnO6 octahedra that share edges with two equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(3)O6 octahedra, and edges with two equivalent Fe(4)O6 octahedra. In the third Sn site, Sn(3) is bonded in a 3-coordinate geometry to one Fe(2), one O(1), one O(3), and one O(5) atom. In the fourth Sn site, Sn(4) is bonded in a 4-coordinate geometry to one Fe(2), one O(1), one O(2), one O(3), and one O(8) atom. Si(1) is bonded to one O(1), one O(2), one O(4), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(3)O6 octahedra, and  a cornercorner with one Fe(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 65-70°. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Sn(3), one Sn(4), and one Si(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Sn(1), one Sn(4), and one Si(1) atom. In the third O site, O(3) is bonded to one Mg(1), one Sn(1), one Sn(3), and one Sn(4) atom to form distorted OMgSn3 tetrahedra that share corners with three equivalent Fe(2)Sn6 octahedra,  a cornercorner with one O(5)Fe2Sn2 tetrahedra,  a cornercorner with one O(6)Fe2Sn2 tetrahedra,  a cornercorner with one O(8)Fe2Sn2 tetrahedra, and  a cornercorner with one O(3)MgSn3 tetrahedra. The corner-sharing octahedral tilt angles range from 50-60°. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to one Mg(1) and one Si(1) atom. In the fifth O site, O(5) is bonded to one Fe(1), one Fe(3), one Sn(2), and one Sn(3) atom to form OFe2Sn2 tetrahedra that share  a cornercorner with one Fe(2)Sn6 octahedra,  a cornercorner with one O(3)MgSn3 tetrahedra, corners with two equivalent O(6)Fe2Sn2 tetrahedra, corners with two equivalent O(8)Fe2Sn2 tetrahedra, corners with two equivalent O(7)Fe3Si tetrahedra, corners with three equivalent O(5)Fe2Sn2 tetrahedra,  an edgeedge with one O(6)Fe2Sn2 tetrahedra,  an edgeedge with one O(8)Fe2Sn2 tetrahedra, and  an edgeedge with one O(7)Fe3Si tetrahedra. The corner-sharing octahedral tilt angles are 46°. In the sixth O site, O(6) is bonded to one Fe(3), one Fe(4), one Sn(1), and one Sn(2) atom to form OFe2Sn2 tetrahedra that share  a cornercorner with one Fe(2)Sn6 octahedra,  a cornercorner with one O(3)MgSn3 tetrahedra, corners with two equivalent O(5)Fe2Sn2 tetrahedra, corners with two equivalent O(8)Fe2Sn2 tetrahedra, corners with two equivalent O(7)Fe3Si tetrahedra, corners with three equivalent O(6)Fe2Sn2 tetrahedra,  an edgeedge with one O(5)Fe2Sn2 tetrahedra,  an edgeedge with one O(8)Fe2Sn2 tetrahedra, and  an edgeedge with one O(7)Fe3Si tetrahedra. The corner-sharing octahedral tilt angles are 47°. In the seventh O site, O(7) is bonded to one Fe(1), one Fe(3), one Fe(4), and one Si(1) atom to form OFe3Si tetrahedra that share corners with two equivalent O(5)Fe2Sn2 tetrahedra, corners with two equivalent O(6)Fe2Sn2 tetrahedra, corners with two equivalent O(8)Fe2Sn2 tetrahedra, corners with three equivalent O(7)Fe3Si tetrahedra,  an edgeedge with one O(5)Fe2Sn2 tetrahedra,  an edgeedge with one O(6)Fe2Sn2 tetrahedra, and  an edgeedge with one O(8)Fe2Sn2 tetrahedra. In the eighth O site, O(8) is bonded to one Fe(1), one Fe(4), one Sn(2), and one Sn(4) atom to form distorted OFe2Sn2 tetrahedra that share  a cornercorner with one Fe(2)Sn6 octahedra,  a cornercorner with one O(3)MgSn3 tetrahedra, corners with two equivalent O(5)Fe2Sn2 tetrahedra, corners with two equivalent O(6)Fe2Sn2 tetrahedra, corners with two equivalent O(7)Fe3Si tetrahedra, corners with three equivalent O(8)Fe2Sn2 tetrahedra,  an edgeedge with one O(5)Fe2Sn2 tetrahedra,  an edgeedge with one O(6)Fe2Sn2 tetrahedra, and  an edgeedge with one O(7)Fe3Si tetrahedra. The corner-sharing octahedral tilt angles are 55°. is represented by the CIF file [CIF]
data_MgFe4Si2Sn7O16
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.038
_cell_length_b   7.031
_cell_length_c   10.028
_cell_angle_alpha   89.899
_cell_angle_beta   90.147
_cell_angle_gamma   119.824
_symmetry_Int_Tables_number   1
_cell_volume   430.487
_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  0.500  0.000  1.0
  Fe  Fe1  1  0.500  1.000  0.500  1.0
  Fe  Fe2  1  0.000  0.000  0.000  1.0
  Fe  Fe3  1  0.000  0.500  0.500  1.0
  Fe  Fe4  1  0.500  0.500  0.500  1.0
  Si  Si5  1  0.338  0.668  0.254  1.0
  Si  Si6  1  0.662  0.332  0.746  1.0
  Sn  Sn7  1  0.181  0.319  0.809  1.0
  Sn  Sn8  1  1.000  1.000  0.500  1.0
  Sn  Sn9  1  0.180  0.862  0.808  1.0
  Sn  Sn10  1  0.662  0.831  0.824  1.0
  Sn  Sn11  1  0.338  0.169  0.176  1.0
  Sn  Sn12  1  0.820  0.138  0.192  1.0
  Sn  Sn13  1  0.819  0.681  0.191  1.0
  O  O14  1  0.470  0.928  0.210  1.0
  O  O15  1  0.468  0.541  0.207  1.0
  O  O16  1  0.314  0.657  0.860  1.0
  O  O17  1  0.530  0.072  0.790  1.0
  O  O18  1  0.096  0.549  0.187  1.0
  O  O19  1  0.842  0.157  0.400  1.0
  O  O20  1  0.904  0.451  0.813  1.0
  O  O21  1  0.160  0.314  0.600  1.0
  O  O22  1  0.532  0.460  0.793  1.0
  O  O23  1  0.675  0.340  0.581  1.0
  O  O24  1  0.840  0.686  0.400  1.0
  O  O25  1  0.686  0.343  0.140  1.0
  O  O26  1  0.307  0.151  0.391  1.0
  O  O27  1  0.325  0.660  0.419  1.0
  O  O28  1  0.158  0.843  0.600  1.0
  O  O29  1  0.693  0.849  0.609  1.0
[/CIF]
.