The structure described by NaFe2(SiO3)4 crystallizes in the monoclinic P2 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 8-coordinate geometry to two equivalent O(11), two equivalent O(2), two equivalent O(7), and two equivalent O(9) atoms. In the second Na site, Na(2) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(10), two equivalent O(12), and two equivalent O(8) atoms. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent O(2), two equivalent O(4), and two equivalent O(9) atoms to form FeO6 octahedra that share corners with two equivalent Si(2)O4 tetrahedra, corners with two equivalent Si(3)O4 tetrahedra, corners with two equivalent Si(4)O4 tetrahedra, and edges with two equivalent Fe(4)O6 octahedra. In the second Fe site, Fe(2) is bonded to two equivalent O(1), two equivalent O(10), and two equivalent O(3) atoms to form FeO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(3)O4 tetrahedra, corners with two equivalent Si(4)O4 tetrahedra, and edges with two equivalent Fe(3)O6 octahedra. In the third Fe site, Fe(3) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(6) atoms to form FeO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, corners with two equivalent Si(3)O4 tetrahedra, and edges with two equivalent Fe(2)O6 octahedra. In the fourth Fe site, Fe(4) is bonded to two equivalent O(2), two equivalent O(4), and two equivalent O(5) atoms to form distorted FeO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, corners with two equivalent Si(4)O4 tetrahedra, and edges with two equivalent Fe(1)O6 octahedra. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(11), one O(5), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one Fe(3)O6 octahedra,  a cornercorner with one Fe(4)O6 octahedra, and corners with two equivalent Si(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 35-62°. In the second Si site, Si(2) is bonded to one O(12), one O(2), one O(6), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(3)O6 octahedra,  a cornercorner with one Fe(4)O6 octahedra, and corners with two equivalent Si(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 36-59°. In the third Si site, Si(3) is bonded to one O(11), one O(3), one O(7), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one Fe(3)O6 octahedra, and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 34-58°. In the fourth Si site, Si(4) is bonded to one O(10), one O(12), one O(4), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one Fe(4)O6 octahedra, and corners with two equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 33-59°. There are twelve inequivalent O sites. In the first O site, O(1) is bonded to one Na(2), one Fe(2), one Fe(3), and one Si(1) atom to form a mixture of distorted corner and edge-sharing ONaFe2Si tetrahedra. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Fe(1), one Fe(4), and one Si(2) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Fe(2), one Fe(3), and one Si(3) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Fe(1), one Fe(4), and one Si(4) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Fe(4) and one Si(1) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one Fe(3) and one Si(2) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Na(1), one Si(1), and one Si(3) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Na(2), one Si(2), and one Si(4) atom. In the ninth O site, O(9) is bonded in a distorted T-shaped geometry to one Na(1), one Fe(1), and one Si(3) atom. In the tenth O site, O(10) is bonded in a distorted T-shaped geometry to one Na(2), one Fe(2), and one Si(4) atom. In the eleventh O site, O(11) is bonded in a distorted bent 150 degrees geometry to one Na(1), one Si(1), and one Si(3) atom. In the twelfth O site, O(12) is bonded in a distorted bent 150 degrees geometry to one Na(2), one Si(2), and one Si(4) atom. is represented by the CIF file [CIF]
data_NaFe2(SiO3)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.357
_cell_length_b   6.568
_cell_length_c   6.568
_cell_angle_alpha   84.196
_cell_angle_beta   76.371
_cell_angle_gamma   76.370
_symmetry_Int_Tables_number   1
_cell_volume   218.010
_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
  Fe  Fe0  1  0.250  0.903  0.097  1.0
  Fe  Fe1  1  0.750  0.102  0.898  1.0
  Na  Na2  1  0.750  0.704  0.296  1.0
  O  O3  1  0.642  0.806  0.963  1.0
  O  O4  1  0.858  0.037  0.194  1.0
  O  O5  1  0.126  0.961  0.812  1.0
  O  O6  1  0.374  0.188  0.039  1.0
  O  O7  1  0.784  0.384  0.908  1.0
  O  O8  1  0.716  0.092  0.616  1.0
  O  O9  1  0.518  0.649  0.651  1.0
  O  O10  1  0.982  0.349  0.351  1.0
  O  O11  1  0.297  0.896  0.382  1.0
  O  O12  1  0.203  0.618  0.104  1.0
  O  O13  1  0.015  0.650  0.637  1.0
  O  O14  1  0.485  0.363  0.350  1.0
  Si  Si15  1  0.739  0.616  0.794  1.0
  Si  Si16  1  0.761  0.206  0.384  1.0
  Si  Si17  1  0.231  0.795  0.619  1.0
  Si  Si18  1  0.269  0.381  0.205  1.0
[/CIF]
.
The structure described by NaFe2(SiO3)4 crystallizes in the monoclinic P2 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 8-coordinate geometry to two equivalent O(11), two equivalent O(2), two equivalent O(7), and two equivalent O(9) atoms. In the second Na site, Na(2) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(10), two equivalent O(12), and two equivalent O(8) atoms. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent O(2), two equivalent O(4), and two equivalent O(9) atoms to form FeO6 octahedra that share corners with two equivalent Si(2)O4 tetrahedra, corners with two equivalent Si(3)O4 tetrahedra, corners with two equivalent Si(4)O4 tetrahedra, and edges with two equivalent Fe(4)O6 octahedra. In the second Fe site, Fe(2) is bonded to two equivalent O(1), two equivalent O(10), and two equivalent O(3) atoms to form FeO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(3)O4 tetrahedra, corners with two equivalent Si(4)O4 tetrahedra, and edges with two equivalent Fe(3)O6 octahedra. In the third Fe site, Fe(3) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(6) atoms to form FeO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, corners with two equivalent Si(3)O4 tetrahedra, and edges with two equivalent Fe(2)O6 octahedra. In the fourth Fe site, Fe(4) is bonded to two equivalent O(2), two equivalent O(4), and two equivalent O(5) atoms to form distorted FeO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, corners with two equivalent Si(4)O4 tetrahedra, and edges with two equivalent Fe(1)O6 octahedra. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(11), one O(5), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one Fe(3)O6 octahedra,  a cornercorner with one Fe(4)O6 octahedra, and corners with two equivalent Si(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 35-62°. In the second Si site, Si(2) is bonded to one O(12), one O(2), one O(6), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(3)O6 octahedra,  a cornercorner with one Fe(4)O6 octahedra, and corners with two equivalent Si(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 36-59°. In the third Si site, Si(3) is bonded to one O(11), one O(3), one O(7), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one Fe(3)O6 octahedra, and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 34-58°. In the fourth Si site, Si(4) is bonded to one O(10), one O(12), one O(4), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one Fe(4)O6 octahedra, and corners with two equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 33-59°. There are twelve inequivalent O sites. In the first O site, O(1) is bonded to one Na(2), one Fe(2), one Fe(3), and one Si(1) atom to form a mixture of distorted corner and edge-sharing ONaFe2Si tetrahedra. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Fe(1), one Fe(4), and one Si(2) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Fe(2), one Fe(3), and one Si(3) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Fe(1), one Fe(4), and one Si(4) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Fe(4) and one Si(1) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one Fe(3) and one Si(2) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Na(1), one Si(1), and one Si(3) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Na(2), one Si(2), and one Si(4) atom. In the ninth O site, O(9) is bonded in a distorted T-shaped geometry to one Na(1), one Fe(1), and one Si(3) atom. In the tenth O site, O(10) is bonded in a distorted T-shaped geometry to one Na(2), one Fe(2), and one Si(4) atom. In the eleventh O site, O(11) is bonded in a distorted bent 150 degrees geometry to one Na(1), one Si(1), and one Si(3) atom. In the twelfth O site, O(12) is bonded in a distorted bent 150 degrees geometry to one Na(2), one Si(2), and one Si(4) atom. is represented by the CIF file [CIF]
data_NaFe2(SiO3)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.357
_cell_length_b   6.568
_cell_length_c   6.568
_cell_angle_alpha   84.196
_cell_angle_beta   76.371
_cell_angle_gamma   76.370
_symmetry_Int_Tables_number   1
_cell_volume   218.010
_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
  Fe  Fe0  1  0.250  0.903  0.097  1.0
  Fe  Fe1  1  0.750  0.102  0.898  1.0
  Na  Na2  1  0.750  0.704  0.296  1.0
  O  O3  1  0.642  0.806  0.963  1.0
  O  O4  1  0.858  0.037  0.194  1.0
  O  O5  1  0.126  0.961  0.812  1.0
  O  O6  1  0.374  0.188  0.039  1.0
  O  O7  1  0.784  0.384  0.908  1.0
  O  O8  1  0.716  0.092  0.616  1.0
  O  O9  1  0.518  0.649  0.651  1.0
  O  O10  1  0.982  0.349  0.351  1.0
  O  O11  1  0.297  0.896  0.382  1.0
  O  O12  1  0.203  0.618  0.104  1.0
  O  O13  1  0.015  0.650  0.637  1.0
  O  O14  1  0.485  0.363  0.350  1.0
  Si  Si15  1  0.739  0.616  0.794  1.0
  Si  Si16  1  0.761  0.206  0.384  1.0
  Si  Si17  1  0.231  0.795  0.619  1.0
  Si  Si18  1  0.269  0.381  0.205  1.0
[/CIF]
.