The material described by NaNb2PO8 crystallizes in the monoclinic P2_1 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to one O(1), one O(10), one O(12), one O(4), one O(5), and one O(9) atom. In the second Na site, Na(2) is bonded in a 7-coordinate geometry to one O(11), one O(12), one O(13), one O(14), one O(15), one O(7), and one O(8) atom. There are four inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(10), one O(15), one O(3), one O(5), one O(7), and one O(9) atom to form NbO6 octahedra that share corners with three equivalent Nb(3)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra, and corners with two equivalent P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 7-20°. In the second Nb site, Nb(2) is bonded to one O(11), one O(13), one O(14), one O(2), and two equivalent O(6) atoms to form NbO6 octahedra that share corners with two equivalent Nb(2)O6 octahedra, corners with three equivalent Nb(4)O6 octahedra, and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 5-23°. In the third Nb site, Nb(3) is bonded to one O(1), one O(3), one O(5), one O(9), and two equivalent O(16) atoms to form NbO6 octahedra that share corners with two equivalent Nb(3)O6 octahedra, corners with three equivalent Nb(1)O6 octahedra, and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 7-20°. In the fourth Nb site, Nb(4) is bonded to one O(11), one O(12), one O(13), one O(2), one O(4), and one O(8) atom to form NbO6 octahedra that share corners with three equivalent Nb(2)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra, and corners with two equivalent P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 5-23°. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(10), one O(12), one O(14), and one O(4) atom to form PO4 tetrahedra that share  a cornercorner with one Nb(1)O6 octahedra,  a cornercorner with one Nb(2)O6 octahedra, and corners with two equivalent Nb(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 12-34°. In the second P site, P(2) is bonded to one O(1), one O(15), one O(7), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Nb(3)O6 octahedra,  a cornercorner with one Nb(4)O6 octahedra, and corners with two equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 8-25°. There are sixteen inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Na(1), one Nb(3), and one P(2) atom. In the second O site, O(2) is bonded in a linear geometry to one Nb(2) and one Nb(4) atom. In the third O site, O(3) is bonded in a linear geometry to one Nb(1) and one Nb(3) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Na(1), one Nb(4), and one P(1) atom. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Na(1), one Nb(1), and one Nb(3) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to two equivalent Nb(2) atoms. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Na(2), one Nb(1), and one P(2) atom. In the eighth O site, O(8) is bonded in a 2-coordinate geometry to one Na(2), one Nb(4), and one P(2) atom. In the ninth O site, O(9) is bonded in a distorted T-shaped geometry to one Na(1), one Nb(1), and one Nb(3) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Na(1), one Nb(1), and one P(1) atom. In the eleventh O site, O(11) is bonded in a distorted T-shaped geometry to one Na(2), one Nb(2), and one Nb(4) atom. In the twelfth O site, O(12) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Nb(4), and one P(1) atom. In the thirteenth O site, O(13) is bonded in a distorted T-shaped geometry to one Na(2), one Nb(2), and one Nb(4) atom. In the fourteenth O site, O(14) is bonded in a 3-coordinate geometry to one Na(2), one Nb(2), and one P(1) atom. In the fifteenth O site, O(15) is bonded in a 3-coordinate geometry to one Na(2), one Nb(1), and one P(2) atom. In the sixteenth O site, O(16) is bonded in a linear geometry to two equivalent Nb(3) atoms. is represented by the CIF card [CIF]
data_NaNb2PO8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.511
_cell_length_b   6.852
_cell_length_c   18.247
_cell_angle_alpha   89.767
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   689.023
_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
  Na  Na0  1  0.714  0.288  0.716  1.0
  Na  Na1  1  0.250  0.789  0.783  1.0
  Na  Na2  1  0.750  0.211  0.217  1.0
  Na  Na3  1  0.214  0.712  0.284  1.0
  Nb  Nb4  1  0.234  0.490  0.627  1.0
  Nb  Nb5  1  0.748  0.339  0.039  1.0
  Nb  Nb6  1  0.744  0.164  0.539  1.0
  Nb  Nb7  1  0.241  0.009  0.126  1.0
  Nb  Nb8  1  0.244  0.836  0.461  1.0
  Nb  Nb9  1  0.734  0.510  0.373  1.0
  Nb  Nb10  1  0.741  0.991  0.874  1.0
  Nb  Nb11  1  0.248  0.661  0.961  1.0
  P  P12  1  0.721  0.692  0.186  1.0
  P  P13  1  0.221  0.308  0.814  1.0
  P  P14  1  0.733  0.810  0.687  1.0
  P  P15  1  0.233  0.190  0.313  1.0
  O  O16  1  0.746  0.992  0.638  1.0
  O  O17  1  0.236  0.842  0.040  1.0
  O  O18  1  0.222  0.658  0.541  1.0
  O  O19  1  0.246  0.008  0.362  1.0
  O  O20  1  0.466  0.787  0.181  1.0
  O  O21  1  0.470  0.668  0.398  1.0
  O  O22  1  0.947  0.523  0.992  1.0
  O  O23  1  0.966  0.213  0.819  1.0
  O  O24  1  0.465  0.315  0.318  1.0
  O  O25  1  0.965  0.685  0.682  1.0
  O  O26  1  0.715  0.884  0.768  1.0
  O  O27  1  0.479  0.325  0.596  1.0
  O  O28  1  0.970  0.332  0.602  1.0
  O  O29  1  0.447  0.477  0.008  1.0
  O  O30  1  0.257  0.377  0.733  1.0
  O  O31  1  0.507  0.808  0.908  1.0
  O  O32  1  0.426  0.163  0.830  1.0
  O  O33  1  0.007  0.192  0.092  1.0
  O  O34  1  0.013  0.847  0.896  1.0
  O  O35  1  0.736  0.158  0.960  1.0
  O  O36  1  0.735  0.508  0.138  1.0
  O  O37  1  0.499  0.691  0.674  1.0
  O  O38  1  0.513  0.153  0.104  1.0
  O  O39  1  0.757  0.623  0.267  1.0
  O  O40  1  0.003  0.017  0.498  1.0
  O  O41  1  0.215  0.116  0.232  1.0
  O  O42  1  0.999  0.309  0.326  1.0
  O  O43  1  0.979  0.675  0.404  1.0
  O  O44  1  0.503  0.983  0.502  1.0
  O  O45  1  0.235  0.492  0.862  1.0
  O  O46  1  0.722  0.342  0.459  1.0
  O  O47  1  0.926  0.837  0.170  1.0
[/CIF]
.
The material described by NaNb2PO8 crystallizes in the monoclinic P2_1 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to one O(1), one O(10), one O(12), one O(4), one O(5), and one O(9) atom. In the second Na site, Na(2) is bonded in a 7-coordinate geometry to one O(11), one O(12), one O(13), one O(14), one O(15), one O(7), and one O(8) atom. There are four inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(10), one O(15), one O(3), one O(5), one O(7), and one O(9) atom to form NbO6 octahedra that share corners with three equivalent Nb(3)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra, and corners with two equivalent P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 7-20°. In the second Nb site, Nb(2) is bonded to one O(11), one O(13), one O(14), one O(2), and two equivalent O(6) atoms to form NbO6 octahedra that share corners with two equivalent Nb(2)O6 octahedra, corners with three equivalent Nb(4)O6 octahedra, and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 5-23°. In the third Nb site, Nb(3) is bonded to one O(1), one O(3), one O(5), one O(9), and two equivalent O(16) atoms to form NbO6 octahedra that share corners with two equivalent Nb(3)O6 octahedra, corners with three equivalent Nb(1)O6 octahedra, and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 7-20°. In the fourth Nb site, Nb(4) is bonded to one O(11), one O(12), one O(13), one O(2), one O(4), and one O(8) atom to form NbO6 octahedra that share corners with three equivalent Nb(2)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra, and corners with two equivalent P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 5-23°. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(10), one O(12), one O(14), and one O(4) atom to form PO4 tetrahedra that share  a cornercorner with one Nb(1)O6 octahedra,  a cornercorner with one Nb(2)O6 octahedra, and corners with two equivalent Nb(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 12-34°. In the second P site, P(2) is bonded to one O(1), one O(15), one O(7), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Nb(3)O6 octahedra,  a cornercorner with one Nb(4)O6 octahedra, and corners with two equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 8-25°. There are sixteen inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Na(1), one Nb(3), and one P(2) atom. In the second O site, O(2) is bonded in a linear geometry to one Nb(2) and one Nb(4) atom. In the third O site, O(3) is bonded in a linear geometry to one Nb(1) and one Nb(3) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Na(1), one Nb(4), and one P(1) atom. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Na(1), one Nb(1), and one Nb(3) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to two equivalent Nb(2) atoms. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Na(2), one Nb(1), and one P(2) atom. In the eighth O site, O(8) is bonded in a 2-coordinate geometry to one Na(2), one Nb(4), and one P(2) atom. In the ninth O site, O(9) is bonded in a distorted T-shaped geometry to one Na(1), one Nb(1), and one Nb(3) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Na(1), one Nb(1), and one P(1) atom. In the eleventh O site, O(11) is bonded in a distorted T-shaped geometry to one Na(2), one Nb(2), and one Nb(4) atom. In the twelfth O site, O(12) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Nb(4), and one P(1) atom. In the thirteenth O site, O(13) is bonded in a distorted T-shaped geometry to one Na(2), one Nb(2), and one Nb(4) atom. In the fourteenth O site, O(14) is bonded in a 3-coordinate geometry to one Na(2), one Nb(2), and one P(1) atom. In the fifteenth O site, O(15) is bonded in a 3-coordinate geometry to one Na(2), one Nb(1), and one P(2) atom. In the sixteenth O site, O(16) is bonded in a linear geometry to two equivalent Nb(3) atoms. is represented by the CIF card [CIF]
data_NaNb2PO8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.511
_cell_length_b   6.852
_cell_length_c   18.247
_cell_angle_alpha   89.767
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   689.023
_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
  Na  Na0  1  0.714  0.288  0.716  1.0
  Na  Na1  1  0.250  0.789  0.783  1.0
  Na  Na2  1  0.750  0.211  0.217  1.0
  Na  Na3  1  0.214  0.712  0.284  1.0
  Nb  Nb4  1  0.234  0.490  0.627  1.0
  Nb  Nb5  1  0.748  0.339  0.039  1.0
  Nb  Nb6  1  0.744  0.164  0.539  1.0
  Nb  Nb7  1  0.241  0.009  0.126  1.0
  Nb  Nb8  1  0.244  0.836  0.461  1.0
  Nb  Nb9  1  0.734  0.510  0.373  1.0
  Nb  Nb10  1  0.741  0.991  0.874  1.0
  Nb  Nb11  1  0.248  0.661  0.961  1.0
  P  P12  1  0.721  0.692  0.186  1.0
  P  P13  1  0.221  0.308  0.814  1.0
  P  P14  1  0.733  0.810  0.687  1.0
  P  P15  1  0.233  0.190  0.313  1.0
  O  O16  1  0.746  0.992  0.638  1.0
  O  O17  1  0.236  0.842  0.040  1.0
  O  O18  1  0.222  0.658  0.541  1.0
  O  O19  1  0.246  0.008  0.362  1.0
  O  O20  1  0.466  0.787  0.181  1.0
  O  O21  1  0.470  0.668  0.398  1.0
  O  O22  1  0.947  0.523  0.992  1.0
  O  O23  1  0.966  0.213  0.819  1.0
  O  O24  1  0.465  0.315  0.318  1.0
  O  O25  1  0.965  0.685  0.682  1.0
  O  O26  1  0.715  0.884  0.768  1.0
  O  O27  1  0.479  0.325  0.596  1.0
  O  O28  1  0.970  0.332  0.602  1.0
  O  O29  1  0.447  0.477  0.008  1.0
  O  O30  1  0.257  0.377  0.733  1.0
  O  O31  1  0.507  0.808  0.908  1.0
  O  O32  1  0.426  0.163  0.830  1.0
  O  O33  1  0.007  0.192  0.092  1.0
  O  O34  1  0.013  0.847  0.896  1.0
  O  O35  1  0.736  0.158  0.960  1.0
  O  O36  1  0.735  0.508  0.138  1.0
  O  O37  1  0.499  0.691  0.674  1.0
  O  O38  1  0.513  0.153  0.104  1.0
  O  O39  1  0.757  0.623  0.267  1.0
  O  O40  1  0.003  0.017  0.498  1.0
  O  O41  1  0.215  0.116  0.232  1.0
  O  O42  1  0.999  0.309  0.326  1.0
  O  O43  1  0.979  0.675  0.404  1.0
  O  O44  1  0.503  0.983  0.502  1.0
  O  O45  1  0.235  0.492  0.862  1.0
  O  O46  1  0.722  0.342  0.459  1.0
  O  O47  1  0.926  0.837  0.170  1.0
[/CIF]
.