The material described by KMgFe(PO4)2 crystallizes in the monoclinic P2_1/c space group. K(1) is bonded in a 8-coordinate geometry to one O(2), one O(3), one O(4), one O(7), two equivalent O(1), and two equivalent O(8) atoms. Mg(1) is bonded to one O(4), one O(6), two equivalent O(3), and two equivalent O(5) atoms to form MgO6 octahedra that share  a cornercorner with one P(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra,  a cornercorner with one Fe(1)O5 trigonal bipyramid, edges with two equivalent Mg(1)O6 octahedra, and  an edgeedge with one P(2)O4 tetrahedra. Fe(1) is bonded to one O(1), one O(2), one O(6), one O(7), and one O(8) atom to form FeO5 trigonal bipyramids that share  a cornercorner with one Mg(1)O6 octahedra, corners with two equivalent P(1)O4 tetrahedra, and corners with three equivalent P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 54°. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form PO4 tetrahedra that share corners with three equivalent Mg(1)O6 octahedra and corners with two equivalent Fe(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 54-57°. In the second P site, P(2) is bonded to one O(5), one O(6), one O(7), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra, corners with three equivalent Fe(1)O5 trigonal bipyramids, and  an edgeedge with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles are 4°. There are eight inequivalent O sites. In the first O site, O(4) is bonded in a 3-coordinate geometry to one K(1), one Mg(1), and one P(1) atom. In the second O site, O(5) is bonded in a distorted T-shaped geometry to two equivalent Mg(1) and one P(2) atom. In the third O site, O(6) is bonded in a distorted trigonal planar geometry to one Mg(1), one Fe(1), and one P(2) atom. In the fourth O site, O(7) is bonded in a 3-coordinate geometry to one K(1), one Fe(1), and one P(2) atom. In the fifth O site, O(8) is bonded in a 2-coordinate geometry to two equivalent K(1), one Fe(1), and one P(2) atom. In the sixth O site, O(1) is bonded in a 2-coordinate geometry to two equivalent K(1), one Fe(1), and one P(1) atom. In the seventh O site, O(2) is bonded in a 2-coordinate geometry to one K(1), one Fe(1), and one P(1) atom. In the eighth O site, O(3) is bonded in a 3-coordinate geometry to one K(1), two equivalent Mg(1), and one P(1) atom. is represented by the CIF card [CIF]
data_KMgFe(PO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   14.672
_cell_length_b   5.241
_cell_length_c   9.325
_cell_angle_alpha   74.967
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   692.493
_cell_formula_units_Z   4
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
  K  K0  1  0.323  0.176  0.180  1.0
  K  K1  1  0.823  0.824  0.320  1.0
  K  K2  1  0.677  0.824  0.820  1.0
  K  K3  1  0.177  0.176  0.680  1.0
  Mg  Mg4  1  0.049  0.241  0.033  1.0
  Mg  Mg5  1  0.549  0.759  0.467  1.0
  Mg  Mg6  1  0.951  0.759  0.967  1.0
  Mg  Mg7  1  0.451  0.241  0.533  1.0
  Fe  Fe8  1  0.128  0.773  0.383  1.0
  Fe  Fe9  1  0.628  0.227  0.117  1.0
  Fe  Fe10  1  0.872  0.227  0.617  1.0
  Fe  Fe11  1  0.372  0.773  0.883  1.0
  P  P12  1  0.173  0.744  0.037  1.0
  P  P13  1  0.673  0.256  0.463  1.0
  P  P14  1  0.827  0.256  0.963  1.0
  P  P15  1  0.327  0.744  0.537  1.0
  P  P16  1  0.007  0.310  0.319  1.0
  P  P17  1  0.507  0.690  0.181  1.0
  P  P18  1  0.993  0.690  0.681  1.0
  P  P19  1  0.493  0.310  0.819  1.0
  O  O20  1  0.244  0.885  0.445  1.0
  O  O21  1  0.744  0.115  0.055  1.0
  O  O22  1  0.756  0.115  0.555  1.0
  O  O23  1  0.256  0.885  0.945  1.0
  O  O24  1  0.189  0.766  0.198  1.0
  O  O25  1  0.689  0.234  0.302  1.0
  O  O26  1  0.811  0.234  0.802  1.0
  O  O27  1  0.311  0.766  0.698  1.0
  O  O28  1  0.087  0.912  0.971  1.0
  O  O29  1  0.587  0.088  0.529  1.0
  O  O30  1  0.913  0.088  0.029  1.0
  O  O31  1  0.413  0.912  0.471  1.0
  O  O32  1  0.166  0.454  0.031  1.0
  O  O33  1  0.666  0.546  0.469  1.0
  O  O34  1  0.834  0.546  0.969  1.0
  O  O35  1  0.334  0.454  0.531  1.0
  O  O36  1  0.987  0.501  0.167  1.0
  O  O37  1  0.487  0.499  0.333  1.0
  O  O38  1  0.013  0.499  0.833  1.0
  O  O39  1  0.513  0.501  0.667  1.0
  O  O40  1  0.048  0.061  0.276  1.0
  O  O41  1  0.548  0.939  0.224  1.0
  O  O42  1  0.952  0.939  0.724  1.0
  O  O43  1  0.452  0.061  0.776  1.0
  O  O44  1  0.078  0.418  0.411  1.0
  O  O45  1  0.578  0.582  0.089  1.0
  O  O46  1  0.922  0.582  0.589  1.0
  O  O47  1  0.422  0.418  0.911  1.0
  O  O48  1  0.919  0.229  0.411  1.0
  O  O49  1  0.419  0.771  0.089  1.0
  O  O50  1  0.081  0.771  0.589  1.0
  O  O51  1  0.581  0.229  0.911  1.0
[/CIF]
.
The material described by KMgFe(PO4)2 crystallizes in the monoclinic P2_1/c space group. K(1) is bonded in a 8-coordinate geometry to one O(2), one O(3), one O(4), one O(7), two equivalent O(1), and two equivalent O(8) atoms. Mg(1) is bonded to one O(4), one O(6), two equivalent O(3), and two equivalent O(5) atoms to form MgO6 octahedra that share  a cornercorner with one P(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra,  a cornercorner with one Fe(1)O5 trigonal bipyramid, edges with two equivalent Mg(1)O6 octahedra, and  an edgeedge with one P(2)O4 tetrahedra. Fe(1) is bonded to one O(1), one O(2), one O(6), one O(7), and one O(8) atom to form FeO5 trigonal bipyramids that share  a cornercorner with one Mg(1)O6 octahedra, corners with two equivalent P(1)O4 tetrahedra, and corners with three equivalent P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 54°. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form PO4 tetrahedra that share corners with three equivalent Mg(1)O6 octahedra and corners with two equivalent Fe(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 54-57°. In the second P site, P(2) is bonded to one O(5), one O(6), one O(7), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra, corners with three equivalent Fe(1)O5 trigonal bipyramids, and  an edgeedge with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles are 4°. There are eight inequivalent O sites. In the first O site, O(4) is bonded in a 3-coordinate geometry to one K(1), one Mg(1), and one P(1) atom. In the second O site, O(5) is bonded in a distorted T-shaped geometry to two equivalent Mg(1) and one P(2) atom. In the third O site, O(6) is bonded in a distorted trigonal planar geometry to one Mg(1), one Fe(1), and one P(2) atom. In the fourth O site, O(7) is bonded in a 3-coordinate geometry to one K(1), one Fe(1), and one P(2) atom. In the fifth O site, O(8) is bonded in a 2-coordinate geometry to two equivalent K(1), one Fe(1), and one P(2) atom. In the sixth O site, O(1) is bonded in a 2-coordinate geometry to two equivalent K(1), one Fe(1), and one P(1) atom. In the seventh O site, O(2) is bonded in a 2-coordinate geometry to one K(1), one Fe(1), and one P(1) atom. In the eighth O site, O(3) is bonded in a 3-coordinate geometry to one K(1), two equivalent Mg(1), and one P(1) atom. is represented by the CIF card [CIF]
data_KMgFe(PO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   14.672
_cell_length_b   5.241
_cell_length_c   9.325
_cell_angle_alpha   74.967
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   692.493
_cell_formula_units_Z   4
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
  K  K0  1  0.323  0.176  0.180  1.0
  K  K1  1  0.823  0.824  0.320  1.0
  K  K2  1  0.677  0.824  0.820  1.0
  K  K3  1  0.177  0.176  0.680  1.0
  Mg  Mg4  1  0.049  0.241  0.033  1.0
  Mg  Mg5  1  0.549  0.759  0.467  1.0
  Mg  Mg6  1  0.951  0.759  0.967  1.0
  Mg  Mg7  1  0.451  0.241  0.533  1.0
  Fe  Fe8  1  0.128  0.773  0.383  1.0
  Fe  Fe9  1  0.628  0.227  0.117  1.0
  Fe  Fe10  1  0.872  0.227  0.617  1.0
  Fe  Fe11  1  0.372  0.773  0.883  1.0
  P  P12  1  0.173  0.744  0.037  1.0
  P  P13  1  0.673  0.256  0.463  1.0
  P  P14  1  0.827  0.256  0.963  1.0
  P  P15  1  0.327  0.744  0.537  1.0
  P  P16  1  0.007  0.310  0.319  1.0
  P  P17  1  0.507  0.690  0.181  1.0
  P  P18  1  0.993  0.690  0.681  1.0
  P  P19  1  0.493  0.310  0.819  1.0
  O  O20  1  0.244  0.885  0.445  1.0
  O  O21  1  0.744  0.115  0.055  1.0
  O  O22  1  0.756  0.115  0.555  1.0
  O  O23  1  0.256  0.885  0.945  1.0
  O  O24  1  0.189  0.766  0.198  1.0
  O  O25  1  0.689  0.234  0.302  1.0
  O  O26  1  0.811  0.234  0.802  1.0
  O  O27  1  0.311  0.766  0.698  1.0
  O  O28  1  0.087  0.912  0.971  1.0
  O  O29  1  0.587  0.088  0.529  1.0
  O  O30  1  0.913  0.088  0.029  1.0
  O  O31  1  0.413  0.912  0.471  1.0
  O  O32  1  0.166  0.454  0.031  1.0
  O  O33  1  0.666  0.546  0.469  1.0
  O  O34  1  0.834  0.546  0.969  1.0
  O  O35  1  0.334  0.454  0.531  1.0
  O  O36  1  0.987  0.501  0.167  1.0
  O  O37  1  0.487  0.499  0.333  1.0
  O  O38  1  0.013  0.499  0.833  1.0
  O  O39  1  0.513  0.501  0.667  1.0
  O  O40  1  0.048  0.061  0.276  1.0
  O  O41  1  0.548  0.939  0.224  1.0
  O  O42  1  0.952  0.939  0.724  1.0
  O  O43  1  0.452  0.061  0.776  1.0
  O  O44  1  0.078  0.418  0.411  1.0
  O  O45  1  0.578  0.582  0.089  1.0
  O  O46  1  0.922  0.582  0.589  1.0
  O  O47  1  0.422  0.418  0.911  1.0
  O  O48  1  0.919  0.229  0.411  1.0
  O  O49  1  0.419  0.771  0.089  1.0
  O  O50  1  0.081  0.771  0.589  1.0
  O  O51  1  0.581  0.229  0.911  1.0
[/CIF]
.