The crystal structure described by Na2Mg5(PO4)4 crystallizes in the triclinic P-1 space group. Na(1) is bonded in a 8-coordinate geometry to one O(1), one O(3), one O(5), one O(7), two equivalent O(2), and two equivalent O(4) atoms. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one O(2), one O(3), one O(4), one O(5), one O(6), and one O(7) atom to form distorted MgO6 octahedra that share  a cornercorner with one P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra,  an edgeedge with one Mg(3)O6 octahedra,  an edgeedge with one P(1)O4 tetrahedra, and edges with two equivalent Mg(2)O5 trigonal bipyramids. In the second Mg site, Mg(2) is bonded to one O(2), one O(5), one O(6), one O(7), and one O(8) atom to form MgO5 trigonal bipyramids that share corners with two equivalent P(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra, and edges with two equivalent Mg(1)O6 octahedra. In the third Mg site, Mg(3) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form MgO6 octahedra that share corners with two equivalent P(1)O4 tetrahedra, corners with four equivalent P(2)O4 tetrahedra, and edges with two equivalent Mg(1)O6 octahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(2), one O(4), one O(7), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra,  a cornercorner with one Mg(3)O6 octahedra, corners with three equivalent Mg(2)O5 trigonal bipyramids, and  an edgeedge with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 44-53°. In the second P site, P(2) is bonded to one O(1), one O(3), one O(5), and one O(6) atom to form PO4 tetrahedra that share corners with two equivalent Mg(3)O6 octahedra, corners with three equivalent Mg(1)O6 octahedra, and corners with two equivalent Mg(2)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 39-54°. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Na(1), one Mg(3), and one P(2) atom. In the second O site, O(2) is bonded to two equivalent Na(1), one Mg(1), one Mg(2), and one P(1) atom to form distorted ONa2Mg2P trigonal bipyramids that share  a cornercorner with one O(3)NaMg2P trigonal pyramid,  an edgeedge with one O(2)Na2Mg2P trigonal bipyramid, and  an edgeedge with one O(3)NaMg2P trigonal pyramid. In the third O site, O(3) is bonded to one Na(1), one Mg(1), one Mg(3), and one P(2) atom to form distorted ONaMg2P trigonal pyramids that share  a cornercorner with one O(2)Na2Mg2P trigonal bipyramid,  a cornercorner with one O(3)NaMg2P trigonal pyramid, and  an edgeedge with one O(2)Na2Mg2P trigonal bipyramid. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to two equivalent Na(1), one Mg(1), one Mg(3), and one P(1) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Na(1), one Mg(1), one Mg(2), and one P(2) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Mg(1), one Mg(2), and one P(2) atom. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Na(1), one Mg(1), one Mg(2), and one P(1) atom. In the eighth O site, O(8) is bonded in a linear geometry to one Mg(2) and one P(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Na2Mg5(PO4)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.223
_cell_length_b   8.016
_cell_length_c   8.216
_cell_angle_alpha   110.746
_cell_angle_beta   90.339
_cell_angle_gamma   101.938
_symmetry_Int_Tables_number   1
_cell_volume   313.556
_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  0.437  0.962  0.705  1.0
  Na  Na1  1  0.563  0.038  0.295  1.0
  Mg  Mg2  1  0.094  0.255  0.780  1.0
  Mg  Mg3  1  0.635  0.408  0.672  1.0
  Mg  Mg4  1  0.906  0.745  0.220  1.0
  Mg  Mg5  1  0.000  0.000  0.000  1.0
  Mg  Mg6  1  0.365  0.592  0.328  1.0
  P  P7  1  0.131  0.213  0.430  1.0
  P  P8  1  0.869  0.787  0.570  1.0
  P  P9  1  0.620  0.302  0.027  1.0
  P  P10  1  0.380  0.698  0.973  1.0
  O  O11  1  0.257  0.830  0.918  1.0
  O  O12  1  0.325  0.186  0.562  1.0
  O  O13  1  0.320  0.217  0.967  1.0
  O  O14  1  0.680  0.783  0.033  1.0
  O  O15  1  0.933  0.970  0.733  1.0
  O  O16  1  0.067  0.030  0.267  1.0
  O  O17  1  0.675  0.814  0.438  1.0
  O  O18  1  0.743  0.170  0.082  1.0
  O  O19  1  0.242  0.673  0.136  1.0
  O  O20  1  0.343  0.508  0.826  1.0
  O  O21  1  0.758  0.327  0.864  1.0
  O  O22  1  0.657  0.492  0.174  1.0
  O  O23  1  0.115  0.752  0.470  1.0
  O  O24  1  0.267  0.369  0.376  1.0
  O  O25  1  0.885  0.248  0.530  1.0
  O  O26  1  0.733  0.631  0.624  1.0
[/CIF]
.
The crystal structure described by Na2Mg5(PO4)4 crystallizes in the triclinic P-1 space group. Na(1) is bonded in a 8-coordinate geometry to one O(1), one O(3), one O(5), one O(7), two equivalent O(2), and two equivalent O(4) atoms. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one O(2), one O(3), one O(4), one O(5), one O(6), and one O(7) atom to form distorted MgO6 octahedra that share  a cornercorner with one P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra,  an edgeedge with one Mg(3)O6 octahedra,  an edgeedge with one P(1)O4 tetrahedra, and edges with two equivalent Mg(2)O5 trigonal bipyramids. In the second Mg site, Mg(2) is bonded to one O(2), one O(5), one O(6), one O(7), and one O(8) atom to form MgO5 trigonal bipyramids that share corners with two equivalent P(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra, and edges with two equivalent Mg(1)O6 octahedra. In the third Mg site, Mg(3) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form MgO6 octahedra that share corners with two equivalent P(1)O4 tetrahedra, corners with four equivalent P(2)O4 tetrahedra, and edges with two equivalent Mg(1)O6 octahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(2), one O(4), one O(7), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra,  a cornercorner with one Mg(3)O6 octahedra, corners with three equivalent Mg(2)O5 trigonal bipyramids, and  an edgeedge with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 44-53°. In the second P site, P(2) is bonded to one O(1), one O(3), one O(5), and one O(6) atom to form PO4 tetrahedra that share corners with two equivalent Mg(3)O6 octahedra, corners with three equivalent Mg(1)O6 octahedra, and corners with two equivalent Mg(2)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 39-54°. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Na(1), one Mg(3), and one P(2) atom. In the second O site, O(2) is bonded to two equivalent Na(1), one Mg(1), one Mg(2), and one P(1) atom to form distorted ONa2Mg2P trigonal bipyramids that share  a cornercorner with one O(3)NaMg2P trigonal pyramid,  an edgeedge with one O(2)Na2Mg2P trigonal bipyramid, and  an edgeedge with one O(3)NaMg2P trigonal pyramid. In the third O site, O(3) is bonded to one Na(1), one Mg(1), one Mg(3), and one P(2) atom to form distorted ONaMg2P trigonal pyramids that share  a cornercorner with one O(2)Na2Mg2P trigonal bipyramid,  a cornercorner with one O(3)NaMg2P trigonal pyramid, and  an edgeedge with one O(2)Na2Mg2P trigonal bipyramid. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to two equivalent Na(1), one Mg(1), one Mg(3), and one P(1) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Na(1), one Mg(1), one Mg(2), and one P(2) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Mg(1), one Mg(2), and one P(2) atom. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Na(1), one Mg(1), one Mg(2), and one P(1) atom. In the eighth O site, O(8) is bonded in a linear geometry to one Mg(2) and one P(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Na2Mg5(PO4)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.223
_cell_length_b   8.016
_cell_length_c   8.216
_cell_angle_alpha   110.746
_cell_angle_beta   90.339
_cell_angle_gamma   101.938
_symmetry_Int_Tables_number   1
_cell_volume   313.556
_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  0.437  0.962  0.705  1.0
  Na  Na1  1  0.563  0.038  0.295  1.0
  Mg  Mg2  1  0.094  0.255  0.780  1.0
  Mg  Mg3  1  0.635  0.408  0.672  1.0
  Mg  Mg4  1  0.906  0.745  0.220  1.0
  Mg  Mg5  1  0.000  0.000  0.000  1.0
  Mg  Mg6  1  0.365  0.592  0.328  1.0
  P  P7  1  0.131  0.213  0.430  1.0
  P  P8  1  0.869  0.787  0.570  1.0
  P  P9  1  0.620  0.302  0.027  1.0
  P  P10  1  0.380  0.698  0.973  1.0
  O  O11  1  0.257  0.830  0.918  1.0
  O  O12  1  0.325  0.186  0.562  1.0
  O  O13  1  0.320  0.217  0.967  1.0
  O  O14  1  0.680  0.783  0.033  1.0
  O  O15  1  0.933  0.970  0.733  1.0
  O  O16  1  0.067  0.030  0.267  1.0
  O  O17  1  0.675  0.814  0.438  1.0
  O  O18  1  0.743  0.170  0.082  1.0
  O  O19  1  0.242  0.673  0.136  1.0
  O  O20  1  0.343  0.508  0.826  1.0
  O  O21  1  0.758  0.327  0.864  1.0
  O  O22  1  0.657  0.492  0.174  1.0
  O  O23  1  0.115  0.752  0.470  1.0
  O  O24  1  0.267  0.369  0.376  1.0
  O  O25  1  0.885  0.248  0.530  1.0
  O  O26  1  0.733  0.631  0.624  1.0
[/CIF]
.