data_KMg3Ni
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.06
_cell_length_b   5.06
_cell_length_c   5.06
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   KMg3Ni
_chemical_formula_sum   'K1 Mg3 Ni1'
_cell_volume   129.32
_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  0.0  0.0  0.0  1.0
  Mg  Mg2  1  0.53  0.0  0.53  1.0
  Mg  Mg3  1  0.53  0.53  0.0  1.0
  Mg  Mg4  1  0.0  0.53  0.53  1.0
  Ni  Ni0  1  0.53  0.53  0.53  1.0

data_KMg3Ni
_symmetry_space_group_name_H-M   R3m
_cell_length_a   7.15
_cell_length_b   7.15
_cell_length_c   8.76
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   KMg3Ni
_chemical_formula_sum   'K3 Mg9 Ni3'
_cell_volume   387.96
_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  0.0  1.0
  Mg  Mg1  9  0.18  0.35  0.35  1.0
  Ni  Ni2  3  0.0  0.0  0.53  1.0

K Mg Mg Mg Ni
KMg3Ni is (Cubic) Perovskite structured and crystallizes in the trigonal R3m space group. K(1) is bonded to twelve equivalent Mg(1) atoms to form KMg12 cuboctahedra that share corners with twelve equivalent K(1)Mg12 cuboctahedra, faces with six equivalent K(1)Mg12 cuboctahedra, and faces with eight equivalent Ni(1)Mg6 octahedra. There are a spread of K(1)-Mg(1) bond distances ranging from 3.37-3.78 Å. Mg(1) is bonded in a distorted linear geometry to four equivalent K(1) and two equivalent Ni(1) atoms. There is one shorter (2.38 Å) and one longer (2.67 Å) Mg(1)-Ni(1) bond length. Ni(1) is bonded to six equivalent Mg(1) atoms to form NiMg6 octahedra that share corners with six equivalent Ni(1)Mg6 octahedra and faces with eight equivalent K(1)Mg12 cuboctahedra. The corner-sharing octahedra are not tilted.