The compound described by Na4CaFe4(PO4)6 crystallizes in the monoclinic C2 space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to one O(5), one O(6), two equivalent O(3), and two equivalent O(4) atoms. In the second Na site, Na(2) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(7), two equivalent O(8), and two equivalent O(9) atoms. In the third Na site, Na(3) is bonded in a 6-coordinate geometry to two equivalent O(2), two equivalent O(4), and two equivalent O(9) atoms. Ca(1) is bonded in a 6-coordinate geometry to two equivalent O(1), two equivalent O(10), and two equivalent O(3) atoms. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(10), one O(11), one O(12), one O(6), and one O(7) atom to form FeO6 octahedra that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra, corners with two equivalent P(4)O4 tetrahedra, and  an edgeedge with one Fe(2)O6 octahedra. In the second Fe site, Fe(2) is bonded to one O(11), one O(12), one O(2), one O(5), one O(8), and one O(9) atom to form FeO6 octahedra that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra, corners with two equivalent P(4)O4 tetrahedra, and  an edgeedge with one Fe(1)O6 octahedra. There are four inequivalent P sites. In the first P site, P(1) is bonded to two equivalent O(1) and two equivalent O(5) atoms to form PO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra and corners with two equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-51°. In the second P site, P(2) is bonded to two equivalent O(2) and two equivalent O(6) atoms to form PO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra and corners with two equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-50°. In the third P site, P(3) is bonded to one O(11), one O(3), one O(7), and one O(9) atom to form PO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra and corners with two equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 40-57°. In the fourth P site, P(4) is bonded to one O(10), one O(12), one O(4), and one O(8) atom to form PO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra and corners with two equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 41-57°. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Na(2), one Ca(1), one Fe(1), and one P(1) atom. In the second O site, O(2) is bonded in a distorted trigonal non-coplanar geometry to one Na(3), one Fe(2), and one P(2) atom. In the third O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Na(1), one Ca(1), and one P(3) atom. In the fourth O site, O(4) is bonded in a distorted rectangular see-saw-like geometry to one Na(3), two equivalent Na(1), and one P(4) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Na(1), one Fe(2), and one P(1) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Na(1), one Fe(1), and one P(2) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Na(2), one Fe(1), and one P(3) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Na(2), one Fe(2), and one P(4) atom. In the ninth O site, O(9) is bonded in a 3-coordinate geometry to one Na(2), one Na(3), one Fe(2), and one P(3) atom. In the tenth O site, O(10) is bonded in a distorted trigonal planar geometry to one Ca(1), one Fe(1), and one P(4) atom. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Fe(1), one Fe(2), and one P(3) atom. In the twelfth O site, O(12) is bonded in a 3-coordinate geometry to one Fe(1), one Fe(2), and one P(4) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Na4CaFe4(PO4)6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.835
_cell_length_b   8.835
_cell_length_c   6.490
_cell_angle_alpha   73.620
_cell_angle_beta   73.620
_cell_angle_gamma   91.495
_symmetry_Int_Tables_number   1
_cell_volume   463.240
_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  0.503  0.497  0.247  1.0
  Na  Na1  1  0.503  0.497  0.753  1.0
  Na  Na2  1  0.006  0.994  0.000  1.0
  Na  Na3  1  0.733  0.267  0.000  1.0
  Ca  Ca4  1  0.263  0.737  0.500  1.0
  Fe  Fe5  1  0.928  0.616  0.392  1.0
  Fe  Fe6  1  0.384  0.072  0.608  1.0
  Fe  Fe7  1  0.065  0.376  0.115  1.0
  Fe  Fe8  1  0.624  0.935  0.885  1.0
  P  P9  1  0.276  0.724  0.000  1.0
  P  P10  1  0.726  0.274  0.500  1.0
  P  P11  1  0.651  0.857  0.383  1.0
  P  P12  1  0.143  0.349  0.617  1.0
  P  P13  1  0.349  0.144  0.115  1.0
  P  P14  1  0.856  0.651  0.885  1.0
  O  O15  1  0.150  0.744  0.212  1.0
  O  O16  1  0.256  0.850  0.788  1.0
  O  O17  1  0.848  0.258  0.286  1.0
  O  O18  1  0.742  0.152  0.714  1.0
  O  O19  1  0.534  0.711  0.436  1.0
  O  O20  1  0.289  0.466  0.564  1.0
  O  O21  1  0.462  0.289  0.070  1.0
  O  O22  1  0.711  0.538  0.930  1.0
  O  O23  1  0.253  0.556  0.974  1.0
  O  O24  1  0.444  0.747  0.026  1.0
  O  O25  1  0.746  0.445  0.521  1.0
  O  O26  1  0.555  0.254  0.479  1.0
  O  O27  1  0.822  0.812  0.368  1.0
  O  O28  1  0.188  0.178  0.632  1.0
  O  O29  1  0.177  0.184  0.125  1.0
  O  O30  1  0.816  0.823  0.875  1.0
  O  O31  1  0.661  0.982  0.155  1.0
  O  O32  1  0.018  0.339  0.845  1.0
  O  O33  1  0.342  0.017  0.344  1.0
  O  O34  1  0.983  0.658  0.656  1.0
  O  O35  1  0.592  0.939  0.576  1.0
  O  O36  1  0.061  0.408  0.424  1.0
  O  O37  1  0.407  0.059  0.925  1.0
  O  O38  1  0.941  0.593  0.075  1.0
[/CIF]
.
The compound described by Na4CaFe4(PO4)6 crystallizes in the monoclinic C2 space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to one O(5), one O(6), two equivalent O(3), and two equivalent O(4) atoms. In the second Na site, Na(2) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(7), two equivalent O(8), and two equivalent O(9) atoms. In the third Na site, Na(3) is bonded in a 6-coordinate geometry to two equivalent O(2), two equivalent O(4), and two equivalent O(9) atoms. Ca(1) is bonded in a 6-coordinate geometry to two equivalent O(1), two equivalent O(10), and two equivalent O(3) atoms. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(10), one O(11), one O(12), one O(6), and one O(7) atom to form FeO6 octahedra that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra, corners with two equivalent P(4)O4 tetrahedra, and  an edgeedge with one Fe(2)O6 octahedra. In the second Fe site, Fe(2) is bonded to one O(11), one O(12), one O(2), one O(5), one O(8), and one O(9) atom to form FeO6 octahedra that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra, corners with two equivalent P(4)O4 tetrahedra, and  an edgeedge with one Fe(1)O6 octahedra. There are four inequivalent P sites. In the first P site, P(1) is bonded to two equivalent O(1) and two equivalent O(5) atoms to form PO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra and corners with two equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-51°. In the second P site, P(2) is bonded to two equivalent O(2) and two equivalent O(6) atoms to form PO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra and corners with two equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-50°. In the third P site, P(3) is bonded to one O(11), one O(3), one O(7), and one O(9) atom to form PO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra and corners with two equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 40-57°. In the fourth P site, P(4) is bonded to one O(10), one O(12), one O(4), and one O(8) atom to form PO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra and corners with two equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 41-57°. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Na(2), one Ca(1), one Fe(1), and one P(1) atom. In the second O site, O(2) is bonded in a distorted trigonal non-coplanar geometry to one Na(3), one Fe(2), and one P(2) atom. In the third O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Na(1), one Ca(1), and one P(3) atom. In the fourth O site, O(4) is bonded in a distorted rectangular see-saw-like geometry to one Na(3), two equivalent Na(1), and one P(4) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Na(1), one Fe(2), and one P(1) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Na(1), one Fe(1), and one P(2) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Na(2), one Fe(1), and one P(3) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Na(2), one Fe(2), and one P(4) atom. In the ninth O site, O(9) is bonded in a 3-coordinate geometry to one Na(2), one Na(3), one Fe(2), and one P(3) atom. In the tenth O site, O(10) is bonded in a distorted trigonal planar geometry to one Ca(1), one Fe(1), and one P(4) atom. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Fe(1), one Fe(2), and one P(3) atom. In the twelfth O site, O(12) is bonded in a 3-coordinate geometry to one Fe(1), one Fe(2), and one P(4) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Na4CaFe4(PO4)6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.835
_cell_length_b   8.835
_cell_length_c   6.490
_cell_angle_alpha   73.620
_cell_angle_beta   73.620
_cell_angle_gamma   91.495
_symmetry_Int_Tables_number   1
_cell_volume   463.240
_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  0.503  0.497  0.247  1.0
  Na  Na1  1  0.503  0.497  0.753  1.0
  Na  Na2  1  0.006  0.994  0.000  1.0
  Na  Na3  1  0.733  0.267  0.000  1.0
  Ca  Ca4  1  0.263  0.737  0.500  1.0
  Fe  Fe5  1  0.928  0.616  0.392  1.0
  Fe  Fe6  1  0.384  0.072  0.608  1.0
  Fe  Fe7  1  0.065  0.376  0.115  1.0
  Fe  Fe8  1  0.624  0.935  0.885  1.0
  P  P9  1  0.276  0.724  0.000  1.0
  P  P10  1  0.726  0.274  0.500  1.0
  P  P11  1  0.651  0.857  0.383  1.0
  P  P12  1  0.143  0.349  0.617  1.0
  P  P13  1  0.349  0.144  0.115  1.0
  P  P14  1  0.856  0.651  0.885  1.0
  O  O15  1  0.150  0.744  0.212  1.0
  O  O16  1  0.256  0.850  0.788  1.0
  O  O17  1  0.848  0.258  0.286  1.0
  O  O18  1  0.742  0.152  0.714  1.0
  O  O19  1  0.534  0.711  0.436  1.0
  O  O20  1  0.289  0.466  0.564  1.0
  O  O21  1  0.462  0.289  0.070  1.0
  O  O22  1  0.711  0.538  0.930  1.0
  O  O23  1  0.253  0.556  0.974  1.0
  O  O24  1  0.444  0.747  0.026  1.0
  O  O25  1  0.746  0.445  0.521  1.0
  O  O26  1  0.555  0.254  0.479  1.0
  O  O27  1  0.822  0.812  0.368  1.0
  O  O28  1  0.188  0.178  0.632  1.0
  O  O29  1  0.177  0.184  0.125  1.0
  O  O30  1  0.816  0.823  0.875  1.0
  O  O31  1  0.661  0.982  0.155  1.0
  O  O32  1  0.018  0.339  0.845  1.0
  O  O33  1  0.342  0.017  0.344  1.0
  O  O34  1  0.983  0.658  0.656  1.0
  O  O35  1  0.592  0.939  0.576  1.0
  O  O36  1  0.061  0.408  0.424  1.0
  O  O37  1  0.407  0.059  0.925  1.0
  O  O38  1  0.941  0.593  0.075  1.0
[/CIF]
.