The material structure described by Na2CaP2O11 crystallizes in the monoclinic Cc space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 3-coordinate geometry to one O(11), one O(7), one O(8), and two equivalent O(6) atoms. In the second Na site, Na(2) is bonded to one O(4), one O(5), one O(9), and two equivalent O(11) atoms to form distorted NaO5 trigonal bipyramids that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra, corners with two equivalent Na(2)O5 trigonal bipyramids, and  an edgeedge with one Ca(1)O6 octahedra. Ca(1) is bonded to one O(1), one O(3), one O(4), one O(5), one O(7), and one O(8) atom to form distorted CaO6 octahedra that share corners with two equivalent P(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra, and  an edgeedge with one Na(2)O5 trigonal bipyramid. 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 Ca(1)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra, and  a cornercorner with one Na(2)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 47-53°. In the second P site, P(2) is bonded to one O(2), one O(5), one O(6), and one O(7) atom to form PO4 tetrahedra that share corners with two equivalent Ca(1)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra, and  a cornercorner with one Na(2)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 50°. There are eleven inequivalent O sites. In the first O site, O(7) is bonded in a distorted trigonal planar geometry to one Na(1), one Ca(1), and one P(2) atom. In the second O site, O(8) is bonded in an L-shaped geometry to one Na(1) and one Ca(1) atom. In the third O site, O(9) is bonded in a bent 150 degrees geometry to one Na(2) and one O(10) atom. In the fourth O site, O(10) is bonded in a single-bond geometry to one O(9) atom. In the fifth O site, O(11) is bonded in a distorted trigonal non-coplanar geometry to one Na(1) and two equivalent Na(2) atoms. In the sixth O site, O(1) is bonded in a distorted bent 120 degrees geometry to one Ca(1) and one P(1) atom. In the seventh O site, O(2) is bonded in a distorted bent 120 degrees geometry to one P(1) and one P(2) atom. In the eighth O site, O(3) is bonded in a distorted bent 120 degrees geometry to one Ca(1) and one P(1) atom. In the ninth O site, O(4) is bonded in a distorted trigonal non-coplanar geometry to one Na(2), one Ca(1), and one P(1) atom. In the tenth O site, O(5) is bonded in a 3-coordinate geometry to one Na(2), one Ca(1), and one P(2) atom. In the eleventh O site, O(6) is bonded in a distorted trigonal planar geometry to two equivalent Na(1) and one P(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Na2CaP2O11
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.981
_cell_length_b   9.981
_cell_length_c   6.016
_cell_angle_alpha   82.206
_cell_angle_beta   82.206
_cell_angle_gamma   119.432
_symmetry_Int_Tables_number   1
_cell_volume   502.736
_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
  Na  Na0  1  0.785  0.920  0.683  1.0
  Na  Na1  1  0.920  0.785  0.183  1.0
  Na  Na2  1  0.304  0.154  0.218  1.0
  Na  Na3  1  0.154  0.304  0.718  1.0
  Ca  Ca4  1  0.497  0.017  0.535  1.0
  Ca  Ca5  1  0.017  0.497  0.035  1.0
  P  P6  1  0.648  0.226  0.950  1.0
  P  P7  1  0.226  0.648  0.450  1.0
  P  P8  1  0.825  0.083  0.122  1.0
  P  P9  1  0.083  0.825  0.622  1.0
  O  O10  1  0.795  0.393  0.872  1.0
  O  O11  1  0.393  0.795  0.372  1.0
  O  O12  1  0.713  0.101  0.958  1.0
  O  O13  1  0.101  0.713  0.458  1.0
  O  O14  1  0.539  0.177  0.788  1.0
  O  O15  1  0.177  0.539  0.288  1.0
  O  O16  1  0.557  0.198  0.198  1.0
  O  O17  1  0.198  0.557  0.698  1.0
  O  O18  1  0.979  0.244  0.067  1.0
  O  O19  1  0.244  0.979  0.567  1.0
  O  O20  1  0.853  0.958  0.035  1.0
  O  O21  1  0.958  0.853  0.535  1.0
  O  O22  1  0.734  0.030  0.373  1.0
  O  O23  1  0.030  0.734  0.873  1.0
  O  O24  1  0.765  0.449  0.237  1.0
  O  O25  1  0.449  0.765  0.737  1.0
  O  O26  1  0.447  0.459  0.029  1.0
  O  O27  1  0.459  0.447  0.529  1.0
  O  O28  1  0.575  0.582  0.468  1.0
  O  O29  1  0.582  0.575  0.968  1.0
  O  O30  1  0.078  0.138  0.436  1.0
  O  O31  1  0.138  0.078  0.936  1.0
[/CIF]
.
The material structure described by Na2CaP2O11 crystallizes in the monoclinic Cc space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 3-coordinate geometry to one O(11), one O(7), one O(8), and two equivalent O(6) atoms. In the second Na site, Na(2) is bonded to one O(4), one O(5), one O(9), and two equivalent O(11) atoms to form distorted NaO5 trigonal bipyramids that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra, corners with two equivalent Na(2)O5 trigonal bipyramids, and  an edgeedge with one Ca(1)O6 octahedra. Ca(1) is bonded to one O(1), one O(3), one O(4), one O(5), one O(7), and one O(8) atom to form distorted CaO6 octahedra that share corners with two equivalent P(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra, and  an edgeedge with one Na(2)O5 trigonal bipyramid. 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 Ca(1)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra, and  a cornercorner with one Na(2)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 47-53°. In the second P site, P(2) is bonded to one O(2), one O(5), one O(6), and one O(7) atom to form PO4 tetrahedra that share corners with two equivalent Ca(1)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra, and  a cornercorner with one Na(2)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 50°. There are eleven inequivalent O sites. In the first O site, O(7) is bonded in a distorted trigonal planar geometry to one Na(1), one Ca(1), and one P(2) atom. In the second O site, O(8) is bonded in an L-shaped geometry to one Na(1) and one Ca(1) atom. In the third O site, O(9) is bonded in a bent 150 degrees geometry to one Na(2) and one O(10) atom. In the fourth O site, O(10) is bonded in a single-bond geometry to one O(9) atom. In the fifth O site, O(11) is bonded in a distorted trigonal non-coplanar geometry to one Na(1) and two equivalent Na(2) atoms. In the sixth O site, O(1) is bonded in a distorted bent 120 degrees geometry to one Ca(1) and one P(1) atom. In the seventh O site, O(2) is bonded in a distorted bent 120 degrees geometry to one P(1) and one P(2) atom. In the eighth O site, O(3) is bonded in a distorted bent 120 degrees geometry to one Ca(1) and one P(1) atom. In the ninth O site, O(4) is bonded in a distorted trigonal non-coplanar geometry to one Na(2), one Ca(1), and one P(1) atom. In the tenth O site, O(5) is bonded in a 3-coordinate geometry to one Na(2), one Ca(1), and one P(2) atom. In the eleventh O site, O(6) is bonded in a distorted trigonal planar geometry to two equivalent Na(1) and one P(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Na2CaP2O11
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.981
_cell_length_b   9.981
_cell_length_c   6.016
_cell_angle_alpha   82.206
_cell_angle_beta   82.206
_cell_angle_gamma   119.432
_symmetry_Int_Tables_number   1
_cell_volume   502.736
_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
  Na  Na0  1  0.785  0.920  0.683  1.0
  Na  Na1  1  0.920  0.785  0.183  1.0
  Na  Na2  1  0.304  0.154  0.218  1.0
  Na  Na3  1  0.154  0.304  0.718  1.0
  Ca  Ca4  1  0.497  0.017  0.535  1.0
  Ca  Ca5  1  0.017  0.497  0.035  1.0
  P  P6  1  0.648  0.226  0.950  1.0
  P  P7  1  0.226  0.648  0.450  1.0
  P  P8  1  0.825  0.083  0.122  1.0
  P  P9  1  0.083  0.825  0.622  1.0
  O  O10  1  0.795  0.393  0.872  1.0
  O  O11  1  0.393  0.795  0.372  1.0
  O  O12  1  0.713  0.101  0.958  1.0
  O  O13  1  0.101  0.713  0.458  1.0
  O  O14  1  0.539  0.177  0.788  1.0
  O  O15  1  0.177  0.539  0.288  1.0
  O  O16  1  0.557  0.198  0.198  1.0
  O  O17  1  0.198  0.557  0.698  1.0
  O  O18  1  0.979  0.244  0.067  1.0
  O  O19  1  0.244  0.979  0.567  1.0
  O  O20  1  0.853  0.958  0.035  1.0
  O  O21  1  0.958  0.853  0.535  1.0
  O  O22  1  0.734  0.030  0.373  1.0
  O  O23  1  0.030  0.734  0.873  1.0
  O  O24  1  0.765  0.449  0.237  1.0
  O  O25  1  0.449  0.765  0.737  1.0
  O  O26  1  0.447  0.459  0.029  1.0
  O  O27  1  0.459  0.447  0.529  1.0
  O  O28  1  0.575  0.582  0.468  1.0
  O  O29  1  0.582  0.575  0.968  1.0
  O  O30  1  0.078  0.138  0.436  1.0
  O  O31  1  0.138  0.078  0.936  1.0
[/CIF]
.