The material structure described by K2MgNd4Nb2O12 crystallizes in the monoclinic C2/m space group. K(1) is bonded in a 7-coordinate geometry to three equivalent O(4) and four equivalent O(2) atoms. Mg(1) is bonded to two equivalent O(4) and four equivalent O(2) atoms to form MgO6 octahedra that share faces with two equivalent Nb(1)O5 trigonal bipyramids. There are two inequivalent Nd sites. In the first Nd site, Nd(1) is bonded in a body-centered cubic geometry to two equivalent O(2), two equivalent O(3), and four equivalent O(1) atoms. In the second Nd site, Nd(2) is bonded in a 7-coordinate geometry to one O(4), two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. Nb(1) is bonded to one O(4), two equivalent O(1), and two equivalent O(2) atoms to form distorted NbO5 trigonal bipyramids that share  a faceface with one Mg(1)O6 octahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Nd(2), two equivalent Nd(1), and one Nb(1) atom to form distorted ONd3Nb tetrahedra that share corners with two equivalent O(4)K3NdMgNb octahedra, corners with six equivalent O(2)K2Nd2MgNb octahedra, corners with two equivalent O(1)Nd3Nb tetrahedra, corners with four equivalent O(3)Nd4 tetrahedra,  an edgeedge with one O(2)K2Nd2MgNb octahedra,  an edgeedge with one O(3)Nd4 tetrahedra, and edges with three equivalent O(1)Nd3Nb tetrahedra. The corner-sharing octahedral tilt angles range from 10-89°. In the second O site, O(2) is bonded to two equivalent K(1), one Mg(1), one Nd(1), one Nd(2), and one Nb(1) atom to form distorted OK2Nd2MgNb octahedra that share  a cornercorner with one O(2)K2Nd2MgNb octahedra, corners with four equivalent O(4)K3NdMgNb octahedra, corners with two equivalent O(3)Nd4 tetrahedra, corners with six equivalent O(1)Nd3Nb tetrahedra,  an edgeedge with one O(2)K2Nd2MgNb octahedra,  an edgeedge with one O(1)Nd3Nb tetrahedra,  an edgeedge with one O(3)Nd4 tetrahedra, faces with two equivalent O(4)K3NdMgNb octahedra, and faces with three equivalent O(2)K2Nd2MgNb octahedra. The corner-sharing octahedral tilt angles range from 0-62°. In the third O site, O(3) is bonded to two equivalent Nd(1) and two equivalent Nd(2) atoms to form ONd4 tetrahedra that share corners with two equivalent O(4)K3NdMgNb octahedra, corners with four equivalent O(2)K2Nd2MgNb octahedra, corners with eight equivalent O(1)Nd3Nb tetrahedra, edges with two equivalent O(2)K2Nd2MgNb octahedra, edges with two equivalent O(1)Nd3Nb tetrahedra, and edges with two equivalent O(3)Nd4 tetrahedra. The corner-sharing octahedral tilt angles range from 41-66°. In the fourth O site, O(4) is bonded to three equivalent K(1), one Mg(1), one Nd(2), and one Nb(1) atom to form distorted OK3NdMgNb octahedra that share corners with three equivalent O(4)K3NdMgNb octahedra, corners with eight equivalent O(2)K2Nd2MgNb octahedra, corners with two equivalent O(3)Nd4 tetrahedra, corners with four equivalent O(1)Nd3Nb tetrahedra, edges with two equivalent O(4)K3NdMgNb octahedra, and faces with four equivalent O(2)K2Nd2MgNb octahedra. The corner-sharing octahedral tilt angles range from 0-62°. is represented by the Crystallographic Information File (CIF) [CIF]
data_K2Nd4MgNb2O12
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.833
_cell_length_b   7.020
_cell_length_c   8.876
_cell_angle_alpha   102.248
_cell_angle_beta   90.000
_cell_angle_gamma   114.548
_symmetry_Int_Tables_number   1
_cell_volume   321.485
_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  0.125  0.251  0.483  1.0
  K  K1  1  0.875  0.749  0.517  1.0
  Nd  Nd2  1  0.120  0.241  0.906  1.0
  Nd  Nd3  1  0.581  0.162  0.194  1.0
  Nd  Nd4  1  0.419  0.838  0.806  1.0
  Nd  Nd5  1  0.880  0.759  0.094  1.0
  Mg  Mg6  1  0.500  0.000  0.500  1.0
  Nb  Nb7  1  0.684  0.368  0.729  1.0
  Nb  Nb8  1  0.316  0.632  0.271  1.0
  O  O9  1  0.016  0.541  0.841  1.0
  O  O10  1  0.221  0.902  0.306  1.0
  O  O11  1  0.246  0.000  0.000  1.0
  O  O12  1  0.779  0.098  0.694  1.0
  O  O13  1  0.681  0.902  0.306  1.0
  O  O14  1  0.754  0.000  0.000  1.0
  O  O15  1  0.319  0.098  0.694  1.0
  O  O16  1  0.984  0.459  0.159  1.0
  O  O17  1  0.658  0.316  0.497  1.0
  O  O18  1  0.342  0.684  0.503  1.0
  O  O19  1  0.476  0.459  0.159  1.0
  O  O20  1  0.524  0.541  0.841  1.0
[/CIF]
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The material structure described by K2MgNd4Nb2O12 crystallizes in the monoclinic C2/m space group. K(1) is bonded in a 7-coordinate geometry to three equivalent O(4) and four equivalent O(2) atoms. Mg(1) is bonded to two equivalent O(4) and four equivalent O(2) atoms to form MgO6 octahedra that share faces with two equivalent Nb(1)O5 trigonal bipyramids. There are two inequivalent Nd sites. In the first Nd site, Nd(1) is bonded in a body-centered cubic geometry to two equivalent O(2), two equivalent O(3), and four equivalent O(1) atoms. In the second Nd site, Nd(2) is bonded in a 7-coordinate geometry to one O(4), two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. Nb(1) is bonded to one O(4), two equivalent O(1), and two equivalent O(2) atoms to form distorted NbO5 trigonal bipyramids that share  a faceface with one Mg(1)O6 octahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Nd(2), two equivalent Nd(1), and one Nb(1) atom to form distorted ONd3Nb tetrahedra that share corners with two equivalent O(4)K3NdMgNb octahedra, corners with six equivalent O(2)K2Nd2MgNb octahedra, corners with two equivalent O(1)Nd3Nb tetrahedra, corners with four equivalent O(3)Nd4 tetrahedra,  an edgeedge with one O(2)K2Nd2MgNb octahedra,  an edgeedge with one O(3)Nd4 tetrahedra, and edges with three equivalent O(1)Nd3Nb tetrahedra. The corner-sharing octahedral tilt angles range from 10-89°. In the second O site, O(2) is bonded to two equivalent K(1), one Mg(1), one Nd(1), one Nd(2), and one Nb(1) atom to form distorted OK2Nd2MgNb octahedra that share  a cornercorner with one O(2)K2Nd2MgNb octahedra, corners with four equivalent O(4)K3NdMgNb octahedra, corners with two equivalent O(3)Nd4 tetrahedra, corners with six equivalent O(1)Nd3Nb tetrahedra,  an edgeedge with one O(2)K2Nd2MgNb octahedra,  an edgeedge with one O(1)Nd3Nb tetrahedra,  an edgeedge with one O(3)Nd4 tetrahedra, faces with two equivalent O(4)K3NdMgNb octahedra, and faces with three equivalent O(2)K2Nd2MgNb octahedra. The corner-sharing octahedral tilt angles range from 0-62°. In the third O site, O(3) is bonded to two equivalent Nd(1) and two equivalent Nd(2) atoms to form ONd4 tetrahedra that share corners with two equivalent O(4)K3NdMgNb octahedra, corners with four equivalent O(2)K2Nd2MgNb octahedra, corners with eight equivalent O(1)Nd3Nb tetrahedra, edges with two equivalent O(2)K2Nd2MgNb octahedra, edges with two equivalent O(1)Nd3Nb tetrahedra, and edges with two equivalent O(3)Nd4 tetrahedra. The corner-sharing octahedral tilt angles range from 41-66°. In the fourth O site, O(4) is bonded to three equivalent K(1), one Mg(1), one Nd(2), and one Nb(1) atom to form distorted OK3NdMgNb octahedra that share corners with three equivalent O(4)K3NdMgNb octahedra, corners with eight equivalent O(2)K2Nd2MgNb octahedra, corners with two equivalent O(3)Nd4 tetrahedra, corners with four equivalent O(1)Nd3Nb tetrahedra, edges with two equivalent O(4)K3NdMgNb octahedra, and faces with four equivalent O(2)K2Nd2MgNb octahedra. The corner-sharing octahedral tilt angles range from 0-62°. is represented by the Crystallographic Information File (CIF) [CIF]
data_K2Nd4MgNb2O12
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.833
_cell_length_b   7.020
_cell_length_c   8.876
_cell_angle_alpha   102.248
_cell_angle_beta   90.000
_cell_angle_gamma   114.548
_symmetry_Int_Tables_number   1
_cell_volume   321.485
_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  0.125  0.251  0.483  1.0
  K  K1  1  0.875  0.749  0.517  1.0
  Nd  Nd2  1  0.120  0.241  0.906  1.0
  Nd  Nd3  1  0.581  0.162  0.194  1.0
  Nd  Nd4  1  0.419  0.838  0.806  1.0
  Nd  Nd5  1  0.880  0.759  0.094  1.0
  Mg  Mg6  1  0.500  0.000  0.500  1.0
  Nb  Nb7  1  0.684  0.368  0.729  1.0
  Nb  Nb8  1  0.316  0.632  0.271  1.0
  O  O9  1  0.016  0.541  0.841  1.0
  O  O10  1  0.221  0.902  0.306  1.0
  O  O11  1  0.246  0.000  0.000  1.0
  O  O12  1  0.779  0.098  0.694  1.0
  O  O13  1  0.681  0.902  0.306  1.0
  O  O14  1  0.754  0.000  0.000  1.0
  O  O15  1  0.319  0.098  0.694  1.0
  O  O16  1  0.984  0.459  0.159  1.0
  O  O17  1  0.658  0.316  0.497  1.0
  O  O18  1  0.342  0.684  0.503  1.0
  O  O19  1  0.476  0.459  0.159  1.0
  O  O20  1  0.524  0.541  0.841  1.0
[/CIF]
.