The material described by Na3CaFe(SiO3)8 crystallizes in the monoclinic C2 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 4-coordinate geometry to two equivalent O(12) and two equivalent O(5) atoms. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to one O(10), one O(3), one O(4), one O(7), one O(8), and one O(9) atom. Ca(1) is bonded in a 8-coordinate geometry to two equivalent O(11), two equivalent O(2), two equivalent O(4), and two equivalent O(6) atoms. Fe(1) is bonded to two equivalent O(5), two equivalent O(7), and two equivalent O(9) atoms to form FeO6 octahedra that share corners with two equivalent Si(3)O4 tetrahedra and corners with four equivalent Si(1)O4 tetrahedra. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(3), one O(5), and one O(9) atom to form SiO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra,  a cornercorner with one Si(3)O4 tetrahedra, and  a cornercorner with one Si(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 27-46°. In the second Si site, Si(2) is bonded to one O(10), one O(2), one O(4), and one O(6) atom to form corner-sharing SiO4 tetrahedra. In the third Si site, Si(3) is bonded to one O(11), one O(2), one O(3), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra, and  a cornercorner with one Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 53°. In the fourth Si site, Si(4) is bonded to one O(1), one O(12), one O(4), and one O(8) atom to form corner-sharing SiO4 tetrahedra. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to one Si(1) and one Si(4) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to one Ca(1), one Si(2), and one Si(3) atom. In the third O site, O(3) is bonded in a 2-coordinate geometry to one Na(2), one Si(1), and one Si(3) atom. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to one Na(2), one Ca(1), one Si(2), and one Si(4) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Na(1), one Fe(1), and one Si(1) atom. In the sixth O site, O(6) is bonded in a distorted bent 120 degrees geometry to one Ca(1) and one Si(2) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Na(2), one Fe(1), and one Si(3) atom. In the eighth O site, O(8) is bonded in a distorted bent 150 degrees geometry to one Na(2) and one Si(4) atom. In the ninth O site, O(9) is bonded in a distorted T-shaped geometry to one Na(2), one Fe(1), and one Si(1) atom. In the tenth O site, O(10) is bonded in a distorted water-like geometry to one Na(2) and one Si(2) atom. In the eleventh O site, O(11) is bonded in a water-like geometry to one Ca(1) and one Si(3) atom. In the twelfth O site, O(12) is bonded in a water-like geometry to one Na(1) and one Si(4) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Na3CaFe(SiO3)8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.889
_cell_length_b   6.889
_cell_length_c   10.560
_cell_angle_alpha   77.193
_cell_angle_beta   77.193
_cell_angle_gamma   83.071
_symmetry_Int_Tables_number   1
_cell_volume   475.215
_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
  Na  Na0  1  0.275  0.725  0.500  1.0
  Na  Na1  1  0.719  0.291  0.245  1.0
  Na  Na2  1  0.709  0.281  0.755  1.0
  Ca  Ca3  1  0.283  0.717  0.000  1.0
  Fe  Fe4  1  0.918  0.082  0.500  1.0
  Si  Si5  1  0.805  0.621  0.492  1.0
  Si  Si6  1  0.800  0.623  0.984  1.0
  Si  Si7  1  0.379  0.195  0.508  1.0
  Si  Si8  1  0.377  0.200  0.016  1.0
  Si  Si9  1  0.198  0.376  0.266  1.0
  Si  Si10  1  0.211  0.372  0.762  1.0
  Si  Si11  1  0.628  0.789  0.238  1.0
  Si  Si12  1  0.624  0.802  0.734  1.0
  O  O13  1  0.675  0.641  0.373  1.0
  O  O14  1  0.655  0.648  0.877  1.0
  O  O15  1  0.359  0.325  0.627  1.0
  O  O16  1  0.352  0.345  0.123  1.0
  O  O17  1  0.350  0.365  0.370  1.0
  O  O18  1  0.347  0.358  0.875  1.0
  O  O19  1  0.642  0.653  0.125  1.0
  O  O20  1  0.635  0.650  0.630  1.0
  O  O21  1  0.953  0.800  0.463  1.0
  O  O22  1  0.985  0.760  0.944  1.0
  O  O23  1  0.200  0.047  0.537  1.0
  O  O24  1  0.240  0.015  0.056  1.0
  O  O25  1  0.027  0.217  0.314  1.0
  O  O26  1  0.007  0.255  0.815  1.0
  O  O27  1  0.745  0.993  0.185  1.0
  O  O28  1  0.783  0.973  0.686  1.0
  O  O29  1  0.890  0.388  0.524  1.0
  O  O30  1  0.915  0.400  0.018  1.0
  O  O31  1  0.612  0.110  0.476  1.0
  O  O32  1  0.600  0.085  0.982  1.0
  O  O33  1  0.103  0.603  0.224  1.0
  O  O34  1  0.092  0.591  0.726  1.0
  O  O35  1  0.409  0.908  0.274  1.0
  O  O36  1  0.397  0.897  0.776  1.0
[/CIF]
.
The material described by Na3CaFe(SiO3)8 crystallizes in the monoclinic C2 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 4-coordinate geometry to two equivalent O(12) and two equivalent O(5) atoms. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to one O(10), one O(3), one O(4), one O(7), one O(8), and one O(9) atom. Ca(1) is bonded in a 8-coordinate geometry to two equivalent O(11), two equivalent O(2), two equivalent O(4), and two equivalent O(6) atoms. Fe(1) is bonded to two equivalent O(5), two equivalent O(7), and two equivalent O(9) atoms to form FeO6 octahedra that share corners with two equivalent Si(3)O4 tetrahedra and corners with four equivalent Si(1)O4 tetrahedra. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(3), one O(5), and one O(9) atom to form SiO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra,  a cornercorner with one Si(3)O4 tetrahedra, and  a cornercorner with one Si(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 27-46°. In the second Si site, Si(2) is bonded to one O(10), one O(2), one O(4), and one O(6) atom to form corner-sharing SiO4 tetrahedra. In the third Si site, Si(3) is bonded to one O(11), one O(2), one O(3), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra, and  a cornercorner with one Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 53°. In the fourth Si site, Si(4) is bonded to one O(1), one O(12), one O(4), and one O(8) atom to form corner-sharing SiO4 tetrahedra. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to one Si(1) and one Si(4) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to one Ca(1), one Si(2), and one Si(3) atom. In the third O site, O(3) is bonded in a 2-coordinate geometry to one Na(2), one Si(1), and one Si(3) atom. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to one Na(2), one Ca(1), one Si(2), and one Si(4) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Na(1), one Fe(1), and one Si(1) atom. In the sixth O site, O(6) is bonded in a distorted bent 120 degrees geometry to one Ca(1) and one Si(2) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Na(2), one Fe(1), and one Si(3) atom. In the eighth O site, O(8) is bonded in a distorted bent 150 degrees geometry to one Na(2) and one Si(4) atom. In the ninth O site, O(9) is bonded in a distorted T-shaped geometry to one Na(2), one Fe(1), and one Si(1) atom. In the tenth O site, O(10) is bonded in a distorted water-like geometry to one Na(2) and one Si(2) atom. In the eleventh O site, O(11) is bonded in a water-like geometry to one Ca(1) and one Si(3) atom. In the twelfth O site, O(12) is bonded in a water-like geometry to one Na(1) and one Si(4) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Na3CaFe(SiO3)8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.889
_cell_length_b   6.889
_cell_length_c   10.560
_cell_angle_alpha   77.193
_cell_angle_beta   77.193
_cell_angle_gamma   83.071
_symmetry_Int_Tables_number   1
_cell_volume   475.215
_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
  Na  Na0  1  0.275  0.725  0.500  1.0
  Na  Na1  1  0.719  0.291  0.245  1.0
  Na  Na2  1  0.709  0.281  0.755  1.0
  Ca  Ca3  1  0.283  0.717  0.000  1.0
  Fe  Fe4  1  0.918  0.082  0.500  1.0
  Si  Si5  1  0.805  0.621  0.492  1.0
  Si  Si6  1  0.800  0.623  0.984  1.0
  Si  Si7  1  0.379  0.195  0.508  1.0
  Si  Si8  1  0.377  0.200  0.016  1.0
  Si  Si9  1  0.198  0.376  0.266  1.0
  Si  Si10  1  0.211  0.372  0.762  1.0
  Si  Si11  1  0.628  0.789  0.238  1.0
  Si  Si12  1  0.624  0.802  0.734  1.0
  O  O13  1  0.675  0.641  0.373  1.0
  O  O14  1  0.655  0.648  0.877  1.0
  O  O15  1  0.359  0.325  0.627  1.0
  O  O16  1  0.352  0.345  0.123  1.0
  O  O17  1  0.350  0.365  0.370  1.0
  O  O18  1  0.347  0.358  0.875  1.0
  O  O19  1  0.642  0.653  0.125  1.0
  O  O20  1  0.635  0.650  0.630  1.0
  O  O21  1  0.953  0.800  0.463  1.0
  O  O22  1  0.985  0.760  0.944  1.0
  O  O23  1  0.200  0.047  0.537  1.0
  O  O24  1  0.240  0.015  0.056  1.0
  O  O25  1  0.027  0.217  0.314  1.0
  O  O26  1  0.007  0.255  0.815  1.0
  O  O27  1  0.745  0.993  0.185  1.0
  O  O28  1  0.783  0.973  0.686  1.0
  O  O29  1  0.890  0.388  0.524  1.0
  O  O30  1  0.915  0.400  0.018  1.0
  O  O31  1  0.612  0.110  0.476  1.0
  O  O32  1  0.600  0.085  0.982  1.0
  O  O33  1  0.103  0.603  0.224  1.0
  O  O34  1  0.092  0.591  0.726  1.0
  O  O35  1  0.409  0.908  0.274  1.0
  O  O36  1  0.397  0.897  0.776  1.0
[/CIF]
.