The compound described by CaFe2(SiO3)4 crystallizes in the monoclinic C2 space group. Ca(1) is bonded in a 8-coordinate geometry to two equivalent O(3), two equivalent O(4), two equivalent O(5), and two equivalent O(6) atoms. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(5) atoms to form FeO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with four equivalent Si(2)O4 tetrahedra, and edges with two equivalent Fe(2)O6 octahedra. In the second Fe site, Fe(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form distorted FeO6 octahedra that share corners with two equivalent Si(2)O4 tetrahedra, corners with four equivalent Si(1)O4 tetrahedra, and edges with two equivalent Fe(1)O6 octahedra. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(3), one O(4), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra, and corners with two equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 37-60°. In the second Si site, Si(2) is bonded to one O(1), one O(4), one O(5), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Fe(2)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 33-59°. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Fe(1), one Fe(2), and one Si(2) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Fe(2) and one Si(1) atom. In the third O site, O(3) is bonded to one Ca(1), one Fe(1), one Fe(2), and one Si(1) atom to form a mixture of distorted corner and edge-sharing OCaFe2Si tetrahedra. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Ca(1), one Si(1), and one Si(2) atom. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Ca(1), one Fe(1), and one Si(2) atom. In the sixth O site, O(6) is bonded in a 2-coordinate geometry to one Ca(1), one Si(1), and one Si(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_CaFe2(SiO3)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.616
_cell_length_b   6.616
_cell_length_c   5.340
_cell_angle_alpha   77.420
_cell_angle_beta   77.420
_cell_angle_gamma   84.798
_symmetry_Int_Tables_number   1
_cell_volume   222.438
_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
  Ca  Ca0  1  0.304  0.696  0.500  1.0
  Fe  Fe1  1  0.092  0.908  0.000  1.0
  Fe  Fe2  1  0.889  0.111  0.500  1.0
  Si  Si3  1  0.799  0.618  0.486  1.0
  Si  Si4  1  0.621  0.798  0.978  1.0
  Si  Si5  1  0.202  0.379  0.022  1.0
  Si  Si6  1  0.382  0.201  0.514  1.0
  O  O7  1  0.044  0.187  0.118  1.0
  O  O8  1  0.610  0.096  0.458  1.0
  O  O9  1  0.198  0.030  0.609  1.0
  O  O10  1  0.655  0.646  0.261  1.0
  O  O11  1  0.904  0.390  0.542  1.0
  O  O12  1  0.813  0.956  0.882  1.0
  O  O13  1  0.384  0.886  0.061  1.0
  O  O14  1  0.114  0.616  0.939  1.0
  O  O15  1  0.628  0.665  0.747  1.0
  O  O16  1  0.354  0.345  0.739  1.0
  O  O17  1  0.970  0.802  0.391  1.0
  O  O18  1  0.335  0.372  0.253  1.0
[/CIF]
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The compound described by CaFe2(SiO3)4 crystallizes in the monoclinic C2 space group. Ca(1) is bonded in a 8-coordinate geometry to two equivalent O(3), two equivalent O(4), two equivalent O(5), and two equivalent O(6) atoms. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(5) atoms to form FeO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with four equivalent Si(2)O4 tetrahedra, and edges with two equivalent Fe(2)O6 octahedra. In the second Fe site, Fe(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form distorted FeO6 octahedra that share corners with two equivalent Si(2)O4 tetrahedra, corners with four equivalent Si(1)O4 tetrahedra, and edges with two equivalent Fe(1)O6 octahedra. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(3), one O(4), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra, and corners with two equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 37-60°. In the second Si site, Si(2) is bonded to one O(1), one O(4), one O(5), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Fe(2)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 33-59°. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Fe(1), one Fe(2), and one Si(2) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Fe(2) and one Si(1) atom. In the third O site, O(3) is bonded to one Ca(1), one Fe(1), one Fe(2), and one Si(1) atom to form a mixture of distorted corner and edge-sharing OCaFe2Si tetrahedra. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Ca(1), one Si(1), and one Si(2) atom. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Ca(1), one Fe(1), and one Si(2) atom. In the sixth O site, O(6) is bonded in a 2-coordinate geometry to one Ca(1), one Si(1), and one Si(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_CaFe2(SiO3)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.616
_cell_length_b   6.616
_cell_length_c   5.340
_cell_angle_alpha   77.420
_cell_angle_beta   77.420
_cell_angle_gamma   84.798
_symmetry_Int_Tables_number   1
_cell_volume   222.438
_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
  Ca  Ca0  1  0.304  0.696  0.500  1.0
  Fe  Fe1  1  0.092  0.908  0.000  1.0
  Fe  Fe2  1  0.889  0.111  0.500  1.0
  Si  Si3  1  0.799  0.618  0.486  1.0
  Si  Si4  1  0.621  0.798  0.978  1.0
  Si  Si5  1  0.202  0.379  0.022  1.0
  Si  Si6  1  0.382  0.201  0.514  1.0
  O  O7  1  0.044  0.187  0.118  1.0
  O  O8  1  0.610  0.096  0.458  1.0
  O  O9  1  0.198  0.030  0.609  1.0
  O  O10  1  0.655  0.646  0.261  1.0
  O  O11  1  0.904  0.390  0.542  1.0
  O  O12  1  0.813  0.956  0.882  1.0
  O  O13  1  0.384  0.886  0.061  1.0
  O  O14  1  0.114  0.616  0.939  1.0
  O  O15  1  0.628  0.665  0.747  1.0
  O  O16  1  0.354  0.345  0.739  1.0
  O  O17  1  0.970  0.802  0.391  1.0
  O  O18  1  0.335  0.372  0.253  1.0
[/CIF]
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