data_K3Mg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.3
_cell_length_b   7.3
_cell_length_c   4.42
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   108.69
_symmetry_Int_Tables_number   1
_chemical_formula_structural   K3Mg
_chemical_formula_sum   'K3 Mg1'
_cell_volume   223.29
_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  0.26  0.0  0.0  1.0
  K  K1  1  0.13  0.97  0.21  1.0
  K  K2  1  0.13  0.03  0.21  1.0
  Mg  Mg3  1  0.0  0.0  0.0  1.0

data_K3Mg
_symmetry_space_group_name_H-M   P1
_cell_length_a   4.42
_cell_length_b   7.3
_cell_length_c   7.3
_cell_angle_alpha   108.69
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   K3Mg
_chemical_formula_sum   'K3 Mg1'
_cell_volume   223.29
_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  -0.0  0.26  0.0  1.0
  K  K1  1  0.21  0.13  0.03  1.0
  K  K2  1  0.21  0.13  0.97  1.0
  Mg  Mg3  1  0.0  0.0  0.0  1.0

K K K Mg
K3Mg crystallizes in the triclinic P1 space group. The structure is zero-dimensional and consists of one K3Mg cluster. There are three inequivalent K sites. In the first K site, K(1) is bonded in a 2-coordinate geometry to one K(2) and one Mg(1) atom. The K(1)-K(2) bond length is 1.29 Å. The K(1)-Mg(1) bond length is 1.88 Å. In the second K site, K(2) is bonded in a single-bond geometry to one K(1) and one K(3) atom. The K(2)-K(3) bond length is 0.48 Å. In the third K site, K(3) is bonded in a distorted single-bond geometry to one K(2) and one Mg(1) atom. The K(3)-Mg(1) bond length is 1.29 Å. Mg(1) is bonded in a 1-coordinate geometry to one K(1) and one K(3) atom.