The crystal structure described by K2CaNd4Nb2O12 crystallizes in the monoclinic Cm space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 7-coordinate geometry to one O(7), two equivalent O(2), two equivalent O(4), and two equivalent O(6) atoms. In the second K site, K(2) is bonded in a 7-coordinate geometry to one O(6), two equivalent O(2), two equivalent O(4), and two equivalent O(7) atoms. Ca(1) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(3), two equivalent O(4), and two equivalent O(5) atoms. There are four inequivalent Nd sites. In the first Nd site, Nd(1) is bonded in a body-centered cubic geometry to two equivalent O(1), two equivalent O(3), two equivalent O(4), and two equivalent O(5) atoms. In the second Nd site, Nd(2) is bonded in a 7-coordinate geometry to one O(6), two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms. In the third Nd site, Nd(3) is bonded in a distorted hexagonal pyramidal geometry to one O(7), two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms. In the fourth Nd site, Nd(4) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 5-coordinate geometry to one O(6), two equivalent O(1), and two equivalent O(4) atoms. In the second Nb site, Nb(2) is bonded in a 5-coordinate geometry to one O(7), two equivalent O(2), and two equivalent O(5) atoms. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to one Ca(1), one Nd(1), one Nd(3), one Nd(4), and one Nb(1) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one K(1), one K(2), one Nd(2), one Nd(4), and one Nb(2) atom. In the third O site, O(3) is bonded to one Ca(1), one Nd(1), one Nd(2), one Nd(3), and one Nd(4) atom to form a mixture of distorted face and edge-sharing OCaNd4 trigonal bipyramids. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to one K(1), one K(2), one Ca(1), one Nd(1), one Nd(3), and one Nb(1) atom. In the fifth O site, O(5) is bonded in a 5-coordinate geometry to one Ca(1), one Nd(1), one Nd(2), one Nd(4), and one Nb(2) atom. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to one K(2), two equivalent K(1), one Nd(2), and one Nb(1) atom. In the seventh O site, O(7) is bonded in a 5-coordinate geometry to one K(1), two equivalent K(2), one Nd(3), and one Nb(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_K2CaNd4Nb2O12
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.866
_cell_length_b   7.152
_cell_length_c   9.147
_cell_angle_alpha   106.051
_cell_angle_beta   89.993
_cell_angle_gamma   114.227
_symmetry_Int_Tables_number   1
_cell_volume   333.504
_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
  K  K0  1  0.117  0.235  0.490  1.0
  K  K1  1  0.887  0.775  0.510  1.0
  Ca  Ca2  1  0.652  0.302  0.979  1.0
  Nd  Nd3  1  0.131  0.262  0.913  1.0
  Nd  Nd4  1  0.569  0.138  0.235  1.0
  Nd  Nd5  1  0.403  0.806  0.794  1.0
  Nd  Nd6  1  0.897  0.794  0.075  1.0
  Nb  Nb7  1  0.662  0.323  0.684  1.0
  Nb  Nb8  1  0.327  0.653  0.288  1.0
  O  O9  1  0.996  0.532  0.842  1.0
  O  O10  1  0.214  0.893  0.291  1.0
  O  O11  1  0.270  0.015  0.003  1.0
  O  O12  1  0.772  0.098  0.722  1.0
  O  O13  1  0.680  0.894  0.291  1.0
  O  O14  1  0.745  0.015  0.003  1.0
  O  O15  1  0.326  0.098  0.721  1.0
  O  O16  1  0.995  0.470  0.155  1.0
  O  O17  1  0.682  0.363  0.490  1.0
  O  O18  1  0.319  0.638  0.491  1.0
  O  O19  1  0.476  0.470  0.154  1.0
  O  O20  1  0.536  0.532  0.842  1.0
[/CIF]
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The crystal structure described by K2CaNd4Nb2O12 crystallizes in the monoclinic Cm space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 7-coordinate geometry to one O(7), two equivalent O(2), two equivalent O(4), and two equivalent O(6) atoms. In the second K site, K(2) is bonded in a 7-coordinate geometry to one O(6), two equivalent O(2), two equivalent O(4), and two equivalent O(7) atoms. Ca(1) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(3), two equivalent O(4), and two equivalent O(5) atoms. There are four inequivalent Nd sites. In the first Nd site, Nd(1) is bonded in a body-centered cubic geometry to two equivalent O(1), two equivalent O(3), two equivalent O(4), and two equivalent O(5) atoms. In the second Nd site, Nd(2) is bonded in a 7-coordinate geometry to one O(6), two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms. In the third Nd site, Nd(3) is bonded in a distorted hexagonal pyramidal geometry to one O(7), two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms. In the fourth Nd site, Nd(4) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 5-coordinate geometry to one O(6), two equivalent O(1), and two equivalent O(4) atoms. In the second Nb site, Nb(2) is bonded in a 5-coordinate geometry to one O(7), two equivalent O(2), and two equivalent O(5) atoms. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to one Ca(1), one Nd(1), one Nd(3), one Nd(4), and one Nb(1) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one K(1), one K(2), one Nd(2), one Nd(4), and one Nb(2) atom. In the third O site, O(3) is bonded to one Ca(1), one Nd(1), one Nd(2), one Nd(3), and one Nd(4) atom to form a mixture of distorted face and edge-sharing OCaNd4 trigonal bipyramids. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to one K(1), one K(2), one Ca(1), one Nd(1), one Nd(3), and one Nb(1) atom. In the fifth O site, O(5) is bonded in a 5-coordinate geometry to one Ca(1), one Nd(1), one Nd(2), one Nd(4), and one Nb(2) atom. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to one K(2), two equivalent K(1), one Nd(2), and one Nb(1) atom. In the seventh O site, O(7) is bonded in a 5-coordinate geometry to one K(1), two equivalent K(2), one Nd(3), and one Nb(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_K2CaNd4Nb2O12
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.866
_cell_length_b   7.152
_cell_length_c   9.147
_cell_angle_alpha   106.051
_cell_angle_beta   89.993
_cell_angle_gamma   114.227
_symmetry_Int_Tables_number   1
_cell_volume   333.504
_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
  K  K0  1  0.117  0.235  0.490  1.0
  K  K1  1  0.887  0.775  0.510  1.0
  Ca  Ca2  1  0.652  0.302  0.979  1.0
  Nd  Nd3  1  0.131  0.262  0.913  1.0
  Nd  Nd4  1  0.569  0.138  0.235  1.0
  Nd  Nd5  1  0.403  0.806  0.794  1.0
  Nd  Nd6  1  0.897  0.794  0.075  1.0
  Nb  Nb7  1  0.662  0.323  0.684  1.0
  Nb  Nb8  1  0.327  0.653  0.288  1.0
  O  O9  1  0.996  0.532  0.842  1.0
  O  O10  1  0.214  0.893  0.291  1.0
  O  O11  1  0.270  0.015  0.003  1.0
  O  O12  1  0.772  0.098  0.722  1.0
  O  O13  1  0.680  0.894  0.291  1.0
  O  O14  1  0.745  0.015  0.003  1.0
  O  O15  1  0.326  0.098  0.721  1.0
  O  O16  1  0.995  0.470  0.155  1.0
  O  O17  1  0.682  0.363  0.490  1.0
  O  O18  1  0.319  0.638  0.491  1.0
  O  O19  1  0.476  0.470  0.154  1.0
  O  O20  1  0.536  0.532  0.842  1.0
[/CIF]
.