The material structure described by Na4MgNbSi2PO12 crystallizes in the monoclinic Cc space group. There are four inequivalent Na sites. In the first Na site, Na(1) is bonded in a 8-coordinate geometry to one O(1), one O(10), one O(11), one O(3), one O(7), one O(9), and two equivalent O(5) atoms. In the second Na site, Na(2) is bonded in a 7-coordinate geometry to one O(11), one O(12), one O(3), one O(4), one O(6), one O(8), and one O(9) atom. In the third Na site, Na(3) is bonded in a 8-coordinate geometry to one O(10), one O(12), one O(4), one O(6), one O(7), one O(8), and two equivalent O(2) atoms. In the fourth Na site, Na(4) is bonded in a distorted hexagonal planar geometry to one O(10), one O(11), one O(12), one O(7), one O(8), and one O(9) atom. Mg(1) is bonded to one O(1), one O(2), one O(3), one O(7), one O(8), and one O(9) atom to form MgO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and corners with two equivalent P(1)O4 tetrahedra. Nb(1) is bonded to one O(10), one O(11), one O(12), one O(4), one O(5), and one O(6) atom to form NbO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and corners with two equivalent P(1)O4 tetrahedra. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(11), one O(2), one O(5), and one O(8) atom to form SiO4 tetrahedra that share corners with two equivalent Mg(1)O6 octahedra and corners with two equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 25-39°. In the second Si site, Si(2) is bonded to one O(12), one O(3), one O(4), and one O(7) atom to form SiO4 tetrahedra that share corners with two equivalent Mg(1)O6 octahedra and corners with two equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 26-40°. P(1) is bonded to one O(1), one O(10), one O(6), and one O(9) atom to form PO4 tetrahedra that share corners with two equivalent Mg(1)O6 octahedra and corners with two equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 26-38°. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Na(1), one Mg(1), and one P(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to two equivalent Na(3), one Mg(1), and one Si(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Na(1), one Na(2), one Mg(1), and one Si(2) atom. In the fourth O site, O(4) is bonded in a distorted bent 150 degrees geometry to one Na(2), one Na(3), one Nb(1), and one Si(2) atom. In the fifth O site, O(5) is bonded in a distorted bent 150 degrees geometry to two equivalent Na(1), one Nb(1), and one Si(1) atom. In the sixth O site, O(6) is bonded in a distorted bent 150 degrees geometry to one Na(2), one Na(3), one Nb(1), and one P(1) atom. In the seventh O site, O(7) is bonded to one Na(1), one Na(3), one Na(4), one Mg(1), and one Si(2) atom to form distorted face-sharing ONa3MgSi trigonal bipyramids. In the eighth O site, O(8) is bonded to one Na(2), one Na(3), one Na(4), one Mg(1), and one Si(1) atom to form distorted face-sharing ONa3MgSi trigonal bipyramids. In the ninth O site, O(9) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(4), one Mg(1), and one P(1) atom. In the tenth O site, O(10) is bonded in a 5-coordinate geometry to one Na(1), one Na(3), one Na(4), one Nb(1), and one P(1) atom. In the eleventh O site, O(11) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(4), one Nb(1), and one Si(1) atom. In the twelfth O site, O(12) is bonded in a 5-coordinate geometry to one Na(2), one Na(3), one Na(4), one Nb(1), and one Si(2) atom. is represented by the CIF file [CIF]
data_Na4MgNbSi2PO12
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.073
_cell_length_b   9.085
_cell_length_c   9.085
_cell_angle_alpha   60.491
_cell_angle_beta   60.277
_cell_angle_gamma   60.277
_symmetry_Int_Tables_number   1
_cell_volume   533.761
_cell_formula_units_Z   2
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
  Mg  Mg0  1  0.353  0.355  0.346  1.0
  Mg  Mg1  1  0.853  0.846  0.855  1.0
  Na  Na2  1  0.618  0.232  0.896  1.0
  Na  Na3  1  0.228  0.879  0.620  1.0
  Na  Na4  1  0.887  0.628  0.220  1.0
  Na  Na5  1  0.728  0.120  0.379  1.0
  Na  Na6  1  0.118  0.396  0.732  1.0
  Na  Na7  1  0.387  0.720  0.128  1.0
  Na  Na8  1  0.491  0.500  0.486  1.0
  Na  Na9  1  0.991  0.986  0.000  1.0
  Nb  Nb10  1  0.650  0.646  0.646  1.0
  Nb  Nb11  1  0.150  0.146  0.146  1.0
  O  O12  1  0.122  0.284  0.519  1.0
  O  O13  1  0.281  0.521  0.131  1.0
  O  O14  1  0.515  0.127  0.293  1.0
  O  O15  1  0.781  0.631  0.021  1.0
  O  O16  1  0.622  0.019  0.784  1.0
  O  O17  1  0.015  0.793  0.627  1.0
  O  O18  1  0.860  0.724  0.496  1.0
  O  O19  1  0.723  0.497  0.859  1.0
  O  O20  1  0.494  0.868  0.724  1.0
  O  O21  1  0.223  0.359  0.997  1.0
  O  O22  1  0.360  0.996  0.224  1.0
  O  O23  1  0.994  0.224  0.368  1.0
  O  O24  1  0.227  0.580  0.432  1.0
  O  O25  1  0.588  0.418  0.233  1.0
  O  O26  1  0.420  0.213  0.599  1.0
  O  O27  1  0.088  0.733  0.918  1.0
  O  O28  1  0.727  0.932  0.080  1.0
  O  O29  1  0.920  0.099  0.713  1.0
  O  O30  1  0.786  0.427  0.550  1.0
  O  O31  1  0.436  0.556  0.773  1.0
  O  O32  1  0.560  0.772  0.432  1.0
  O  O33  1  0.936  0.273  0.056  1.0
  O  O34  1  0.286  0.050  0.927  1.0
  O  O35  1  0.060  0.932  0.272  1.0
  P  P36  1  0.961  0.254  0.542  1.0
  P  P37  1  0.461  0.042  0.754  1.0
  Si  Si38  1  0.252  0.550  0.958  1.0
  Si  Si39  1  0.549  0.960  0.253  1.0
  Si  Si40  1  0.752  0.458  0.050  1.0
  Si  Si41  1  0.049  0.753  0.460  1.0
[/CIF]
.
The material structure described by Na4MgNbSi2PO12 crystallizes in the monoclinic Cc space group. There are four inequivalent Na sites. In the first Na site, Na(1) is bonded in a 8-coordinate geometry to one O(1), one O(10), one O(11), one O(3), one O(7), one O(9), and two equivalent O(5) atoms. In the second Na site, Na(2) is bonded in a 7-coordinate geometry to one O(11), one O(12), one O(3), one O(4), one O(6), one O(8), and one O(9) atom. In the third Na site, Na(3) is bonded in a 8-coordinate geometry to one O(10), one O(12), one O(4), one O(6), one O(7), one O(8), and two equivalent O(2) atoms. In the fourth Na site, Na(4) is bonded in a distorted hexagonal planar geometry to one O(10), one O(11), one O(12), one O(7), one O(8), and one O(9) atom. Mg(1) is bonded to one O(1), one O(2), one O(3), one O(7), one O(8), and one O(9) atom to form MgO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and corners with two equivalent P(1)O4 tetrahedra. Nb(1) is bonded to one O(10), one O(11), one O(12), one O(4), one O(5), and one O(6) atom to form NbO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and corners with two equivalent P(1)O4 tetrahedra. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(11), one O(2), one O(5), and one O(8) atom to form SiO4 tetrahedra that share corners with two equivalent Mg(1)O6 octahedra and corners with two equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 25-39°. In the second Si site, Si(2) is bonded to one O(12), one O(3), one O(4), and one O(7) atom to form SiO4 tetrahedra that share corners with two equivalent Mg(1)O6 octahedra and corners with two equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 26-40°. P(1) is bonded to one O(1), one O(10), one O(6), and one O(9) atom to form PO4 tetrahedra that share corners with two equivalent Mg(1)O6 octahedra and corners with two equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 26-38°. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Na(1), one Mg(1), and one P(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to two equivalent Na(3), one Mg(1), and one Si(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Na(1), one Na(2), one Mg(1), and one Si(2) atom. In the fourth O site, O(4) is bonded in a distorted bent 150 degrees geometry to one Na(2), one Na(3), one Nb(1), and one Si(2) atom. In the fifth O site, O(5) is bonded in a distorted bent 150 degrees geometry to two equivalent Na(1), one Nb(1), and one Si(1) atom. In the sixth O site, O(6) is bonded in a distorted bent 150 degrees geometry to one Na(2), one Na(3), one Nb(1), and one P(1) atom. In the seventh O site, O(7) is bonded to one Na(1), one Na(3), one Na(4), one Mg(1), and one Si(2) atom to form distorted face-sharing ONa3MgSi trigonal bipyramids. In the eighth O site, O(8) is bonded to one Na(2), one Na(3), one Na(4), one Mg(1), and one Si(1) atom to form distorted face-sharing ONa3MgSi trigonal bipyramids. In the ninth O site, O(9) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(4), one Mg(1), and one P(1) atom. In the tenth O site, O(10) is bonded in a 5-coordinate geometry to one Na(1), one Na(3), one Na(4), one Nb(1), and one P(1) atom. In the eleventh O site, O(11) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(4), one Nb(1), and one Si(1) atom. In the twelfth O site, O(12) is bonded in a 5-coordinate geometry to one Na(2), one Na(3), one Na(4), one Nb(1), and one Si(2) atom. is represented by the CIF file [CIF]
data_Na4MgNbSi2PO12
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.073
_cell_length_b   9.085
_cell_length_c   9.085
_cell_angle_alpha   60.491
_cell_angle_beta   60.277
_cell_angle_gamma   60.277
_symmetry_Int_Tables_number   1
_cell_volume   533.761
_cell_formula_units_Z   2
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
  Mg  Mg0  1  0.353  0.355  0.346  1.0
  Mg  Mg1  1  0.853  0.846  0.855  1.0
  Na  Na2  1  0.618  0.232  0.896  1.0
  Na  Na3  1  0.228  0.879  0.620  1.0
  Na  Na4  1  0.887  0.628  0.220  1.0
  Na  Na5  1  0.728  0.120  0.379  1.0
  Na  Na6  1  0.118  0.396  0.732  1.0
  Na  Na7  1  0.387  0.720  0.128  1.0
  Na  Na8  1  0.491  0.500  0.486  1.0
  Na  Na9  1  0.991  0.986  0.000  1.0
  Nb  Nb10  1  0.650  0.646  0.646  1.0
  Nb  Nb11  1  0.150  0.146  0.146  1.0
  O  O12  1  0.122  0.284  0.519  1.0
  O  O13  1  0.281  0.521  0.131  1.0
  O  O14  1  0.515  0.127  0.293  1.0
  O  O15  1  0.781  0.631  0.021  1.0
  O  O16  1  0.622  0.019  0.784  1.0
  O  O17  1  0.015  0.793  0.627  1.0
  O  O18  1  0.860  0.724  0.496  1.0
  O  O19  1  0.723  0.497  0.859  1.0
  O  O20  1  0.494  0.868  0.724  1.0
  O  O21  1  0.223  0.359  0.997  1.0
  O  O22  1  0.360  0.996  0.224  1.0
  O  O23  1  0.994  0.224  0.368  1.0
  O  O24  1  0.227  0.580  0.432  1.0
  O  O25  1  0.588  0.418  0.233  1.0
  O  O26  1  0.420  0.213  0.599  1.0
  O  O27  1  0.088  0.733  0.918  1.0
  O  O28  1  0.727  0.932  0.080  1.0
  O  O29  1  0.920  0.099  0.713  1.0
  O  O30  1  0.786  0.427  0.550  1.0
  O  O31  1  0.436  0.556  0.773  1.0
  O  O32  1  0.560  0.772  0.432  1.0
  O  O33  1  0.936  0.273  0.056  1.0
  O  O34  1  0.286  0.050  0.927  1.0
  O  O35  1  0.060  0.932  0.272  1.0
  P  P36  1  0.961  0.254  0.542  1.0
  P  P37  1  0.461  0.042  0.754  1.0
  Si  Si38  1  0.252  0.550  0.958  1.0
  Si  Si39  1  0.549  0.960  0.253  1.0
  Si  Si40  1  0.752  0.458  0.050  1.0
  Si  Si41  1  0.049  0.753  0.460  1.0
[/CIF]
.