The material described by CaNdNb2O7 crystallizes in the orthorhombic Imma space group. Ca(1) is bonded to two equivalent O(1), two equivalent O(4), and four equivalent O(3) atoms to form distorted CaO8 hexagonal bipyramids that share edges with two equivalent Ca(1)O8 hexagonal bipyramids, edges with four equivalent Nd(1)O8 hexagonal bipyramids, edges with two equivalent Nb(1)O6 octahedra, and edges with four equivalent Nb(2)O6 octahedra. Nd(1) is bonded to two equivalent O(2), two equivalent O(4), and four equivalent O(3) atoms to form distorted NdO8 hexagonal bipyramids that share edges with two equivalent Nd(1)O8 hexagonal bipyramids, edges with four equivalent Ca(1)O8 hexagonal bipyramids, edges with two equivalent Nb(2)O6 octahedra, and edges with four equivalent Nb(1)O6 octahedra. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form NbO6 octahedra that share corners with two equivalent Nb(1)O6 octahedra, corners with four equivalent Nb(2)O6 octahedra, edges with two equivalent Ca(1)O8 hexagonal bipyramids, and edges with four equivalent Nd(1)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 46-49°. In the second Nb site, Nb(2) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form NbO6 octahedra that share corners with two equivalent Nb(2)O6 octahedra, corners with four equivalent Nb(1)O6 octahedra, edges with two equivalent Nd(1)O8 hexagonal bipyramids, and edges with four equivalent Ca(1)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 42-46°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Ca(1) and two equivalent Nb(2) atoms. In the second O site, O(2) is bonded to two equivalent Nd(1) and two equivalent Nb(1) atoms to form distorted ONd2Nb2 tetrahedra that share corners with two equivalent O(4)Ca2Nd2 tetrahedra, corners with four equivalent O(2)Nd2Nb2 tetrahedra, and  an edgeedge with one O(4)Ca2Nd2 tetrahedra. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Ca(1), one Nd(1), one Nb(1), and one Nb(2) atom. In the fourth O site, O(4) is bonded to two equivalent Ca(1) and two equivalent Nd(1) atoms to form OCa2Nd2 tetrahedra that share corners with two equivalent O(2)Nd2Nb2 tetrahedra, corners with four equivalent O(4)Ca2Nd2 tetrahedra, and  an edgeedge with one O(2)Nd2Nb2 tetrahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_CaNdNb2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.516
_cell_length_b   7.516
_cell_length_c   7.516
_cell_angle_alpha   120.461
_cell_angle_beta   119.580
_cell_angle_gamma   89.966
_symmetry_Int_Tables_number   1
_cell_volume   300.126
_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
  Ca  Ca0  1  0.500  0.500  0.500  1.0
  Ca  Ca1  1  0.500  0.000  0.000  1.0
  Nd  Nd2  1  0.500  0.500  0.000  1.0
  Nd  Nd3  1  0.000  0.500  0.500  1.0
  Nb  Nb4  1  0.000  0.000  0.500  1.0
  Nb  Nb5  1  0.000  0.500  0.000  1.0
  Nb  Nb6  1  0.000  0.000  0.000  1.0
  Nb  Nb7  1  0.500  0.000  0.500  1.0
  O  O8  1  0.319  0.069  0.250  1.0
  O  O9  1  0.920  0.670  0.250  1.0
  O  O10  1  0.324  0.675  0.246  1.0
  O  O11  1  0.928  0.077  0.254  1.0
  O  O12  1  0.324  0.077  0.649  1.0
  O  O13  1  0.928  0.675  0.851  1.0
  O  O14  1  0.681  0.931  0.750  1.0
  O  O15  1  0.080  0.330  0.750  1.0
  O  O16  1  0.676  0.325  0.754  1.0
  O  O17  1  0.072  0.923  0.746  1.0
  O  O18  1  0.676  0.923  0.351  1.0
  O  O19  1  0.072  0.325  0.149  1.0
  O  O20  1  0.376  0.626  0.750  1.0
  O  O21  1  0.624  0.374  0.250  1.0
[/CIF]
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The material described by CaNdNb2O7 crystallizes in the orthorhombic Imma space group. Ca(1) is bonded to two equivalent O(1), two equivalent O(4), and four equivalent O(3) atoms to form distorted CaO8 hexagonal bipyramids that share edges with two equivalent Ca(1)O8 hexagonal bipyramids, edges with four equivalent Nd(1)O8 hexagonal bipyramids, edges with two equivalent Nb(1)O6 octahedra, and edges with four equivalent Nb(2)O6 octahedra. Nd(1) is bonded to two equivalent O(2), two equivalent O(4), and four equivalent O(3) atoms to form distorted NdO8 hexagonal bipyramids that share edges with two equivalent Nd(1)O8 hexagonal bipyramids, edges with four equivalent Ca(1)O8 hexagonal bipyramids, edges with two equivalent Nb(2)O6 octahedra, and edges with four equivalent Nb(1)O6 octahedra. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form NbO6 octahedra that share corners with two equivalent Nb(1)O6 octahedra, corners with four equivalent Nb(2)O6 octahedra, edges with two equivalent Ca(1)O8 hexagonal bipyramids, and edges with four equivalent Nd(1)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 46-49°. In the second Nb site, Nb(2) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form NbO6 octahedra that share corners with two equivalent Nb(2)O6 octahedra, corners with four equivalent Nb(1)O6 octahedra, edges with two equivalent Nd(1)O8 hexagonal bipyramids, and edges with four equivalent Ca(1)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 42-46°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Ca(1) and two equivalent Nb(2) atoms. In the second O site, O(2) is bonded to two equivalent Nd(1) and two equivalent Nb(1) atoms to form distorted ONd2Nb2 tetrahedra that share corners with two equivalent O(4)Ca2Nd2 tetrahedra, corners with four equivalent O(2)Nd2Nb2 tetrahedra, and  an edgeedge with one O(4)Ca2Nd2 tetrahedra. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Ca(1), one Nd(1), one Nb(1), and one Nb(2) atom. In the fourth O site, O(4) is bonded to two equivalent Ca(1) and two equivalent Nd(1) atoms to form OCa2Nd2 tetrahedra that share corners with two equivalent O(2)Nd2Nb2 tetrahedra, corners with four equivalent O(4)Ca2Nd2 tetrahedra, and  an edgeedge with one O(2)Nd2Nb2 tetrahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_CaNdNb2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.516
_cell_length_b   7.516
_cell_length_c   7.516
_cell_angle_alpha   120.461
_cell_angle_beta   119.580
_cell_angle_gamma   89.966
_symmetry_Int_Tables_number   1
_cell_volume   300.126
_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
  Ca  Ca0  1  0.500  0.500  0.500  1.0
  Ca  Ca1  1  0.500  0.000  0.000  1.0
  Nd  Nd2  1  0.500  0.500  0.000  1.0
  Nd  Nd3  1  0.000  0.500  0.500  1.0
  Nb  Nb4  1  0.000  0.000  0.500  1.0
  Nb  Nb5  1  0.000  0.500  0.000  1.0
  Nb  Nb6  1  0.000  0.000  0.000  1.0
  Nb  Nb7  1  0.500  0.000  0.500  1.0
  O  O8  1  0.319  0.069  0.250  1.0
  O  O9  1  0.920  0.670  0.250  1.0
  O  O10  1  0.324  0.675  0.246  1.0
  O  O11  1  0.928  0.077  0.254  1.0
  O  O12  1  0.324  0.077  0.649  1.0
  O  O13  1  0.928  0.675  0.851  1.0
  O  O14  1  0.681  0.931  0.750  1.0
  O  O15  1  0.080  0.330  0.750  1.0
  O  O16  1  0.676  0.325  0.754  1.0
  O  O17  1  0.072  0.923  0.746  1.0
  O  O18  1  0.676  0.923  0.351  1.0
  O  O19  1  0.072  0.325  0.149  1.0
  O  O20  1  0.376  0.626  0.750  1.0
  O  O21  1  0.624  0.374  0.250  1.0
[/CIF]
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