data_KSi
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.43
_cell_length_b   5.43
_cell_length_c   5.43
_cell_angle_alpha   122.3
_cell_angle_beta   122.3
_cell_angle_gamma   86.06
_symmetry_Int_Tables_number   1
_chemical_formula_structural   KSi
_chemical_formula_sum   'K2 Si2'
_cell_volume   109.25
_cell_formula_units_Z   2
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  0.62  0.0  0.99  1.0
  K  K1  1  0.0  0.0  0.97  1.0
  Si  Si2  1  0.0  0.62  0.99  1.0
  Si  Si3  1  0.0  0.0  0.0  1.0

data_KSi
_symmetry_space_group_name_H-M   P1
_cell_length_a   5.24
_cell_length_b   5.24
_cell_length_c   5.43
_cell_angle_alpha   118.85
_cell_angle_beta   118.85
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   KSi
_chemical_formula_sum   'K2 Si2'
_cell_volume   109.25
_cell_formula_units_Z   2
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  0.97  0.97  0.97  1.0
  K  K1  1  0.99  0.36  0.36  1.0
  Si  Si2  1  0.0  0.0  0.0  1.0
  Si  Si3  1  0.36  0.99  0.36  1.0

K K Si Si
K K Si Si 0 3 + o + 0 1 + o o 1 3 o o + 1 2 o - o 2 3 o + + 
KSi crystallizes in the triclinic P1 space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a distorted single-bond geometry to one Si(2) and three equivalent Si(1) atoms. The K(1)-Si(2) bond length is 2.01 Å. There is one shorter (2.80 Å) and two longer (3.82 Å) K(1)-Si(1) bond lengths. In the second K site, K(2) is bonded in a single-bond geometry to one Si(2) and two equivalent Si(1) atoms. The K(2)-Si(2) bond length is 0.15 Å. There is one shorter (2.09 Å) and one longer (3.34 Å) K(2)-Si(1) bond length. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a distorted hexagonal planar geometry to two equivalent K(2), three equivalent K(1), and one Si(2) atom. The Si(1)-Si(2) bond length is 2.01 Å. In the second Si site, Si(2) is bonded in a single-bond geometry to one K(1), one K(2), and one Si(1) atom.