data_KMgNbCd
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.2
_cell_length_b   5.2
_cell_length_c   5.2
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   KMgNbCd
_chemical_formula_sum   'K1 Mg1 Nb1 Cd1'
_cell_volume   99.28
_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  K1  1  0.84  0.84  0.84  1.0
  Mg  Mg2  1  0.0  0.0  0.0  1.0
  Nb  Nb3  1  0.68  0.68  0.68  1.0
  Cd  Cd0  1  0.51  0.51  0.51  1.0

data_KMgNbCd
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.2
_cell_length_b   5.2
_cell_length_c   12.73
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   KMgNbCd
_chemical_formula_sum   'K3 Mg3 Nb3 Cd3'
_cell_volume   297.83
_cell_formula_units_Z   3
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  '-y, x-y, z'
  3  '-x+y, -x, z'
  4  '-y, -x, z'
  5  '-x+y, y, z'
  6  'x, x-y, z'
  7  'x+1/3, y+2/3, z+2/3'
  8  '-y+1/3, x-y+2/3, z+2/3'
  9  '-x+y+1/3, -x+2/3, z+2/3'
  10  '-y+1/3, -x+2/3, z+2/3'
  11  '-x+y+1/3, y+2/3, z+2/3'
  12  'x+1/3, x-y+2/3, z+2/3'
  13  'x+2/3, y+1/3, z+1/3'
  14  '-y+2/3, x-y+1/3, z+1/3'
  15  '-x+y+2/3, -x+1/3, z+1/3'
  16  '-y+2/3, -x+1/3, z+1/3'
  17  '-x+y+2/3, y+1/3, z+1/3'
  18  'x+2/3, x-y+1/3, z+1/3'
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  3  0.0  0.0  0.16  1.0
  Mg  Mg1  3  0.0  0.0  0.0  1.0
  Nb  Nb2  3  0.0  0.0  0.32  1.0
  Cd  Cd3  3  0.0  0.0  0.49  1.0

K Mg Nb Cd
K Mg Nb Cd 0 2 o o o 0 1 + + + 2 3 o o o 
KMgNbCd crystallizes in the trigonal R3m space group. K(1) is bonded to one Mg(1), one Nb(1), and three equivalent Cd(1) atoms to form distorted KMgNbCd3 trigonal bipyramids that share corners with six equivalent K(1)MgNbCd3 trigonal bipyramids and  a cornercorner with one Cd(1)K3Nb trigonal pyramid. The K(1)-Mg(1) bond length is 2.07 Å. The K(1)-Nb(1) bond length is 2.07 Å. All K(1)-Cd(1) bond lengths are 3.00 Å. Mg(1) is bonded in a distorted single-bond geometry to one K(1) atom. Nb(1) is bonded in a 1-coordinate geometry to one K(1) and one Cd(1) atom. The Nb(1)-Cd(1) bond length is 2.07 Å. Cd(1) is bonded to three equivalent K(1) and one Nb(1) atom to form CdK3Nb trigonal pyramids that share  a cornercorner with one K(1)MgNbCd3 trigonal bipyramid and corners with six equivalent Cd(1)K3Nb trigonal pyramids.