The compound described by K2HgCl4 crystallizes in the orthorhombic Pbam space group. There are two inequivalent K sites. In the first K site, K(1) is bonded to three equivalent Cl(1) and four equivalent Cl(3) atoms to form distorted KCl7 pentagonal bipyramids that share corners with two equivalent Hg(1)Cl6 octahedra, corners with two equivalent K(1)Cl7 pentagonal bipyramids, corners with four equivalent K(2)Cl7 pentagonal bipyramids, edges with four equivalent Hg(1)Cl6 octahedra,  an edgeedge with one K(1)Cl7 pentagonal bipyramid, edges with two equivalent K(2)Cl7 pentagonal bipyramids, and faces with two equivalent K(1)Cl7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 50°. In the second K site, K(2) is bonded to three equivalent Cl(2) and four equivalent Cl(3) atoms to form distorted KCl7 pentagonal bipyramids that share corners with two equivalent Hg(1)Cl6 octahedra, corners with two equivalent K(2)Cl7 pentagonal bipyramids, corners with four equivalent K(1)Cl7 pentagonal bipyramids, edges with four equivalent Hg(1)Cl6 octahedra,  an edgeedge with one K(2)Cl7 pentagonal bipyramid, edges with two equivalent K(1)Cl7 pentagonal bipyramids, and faces with two equivalent K(2)Cl7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 50°. Hg(1) is bonded to two equivalent Cl(1), two equivalent Cl(2), and two equivalent Cl(3) atoms to form HgCl6 octahedra that share corners with two equivalent K(1)Cl7 pentagonal bipyramids, corners with two equivalent K(2)Cl7 pentagonal bipyramids, edges with two equivalent Hg(1)Cl6 octahedra, edges with four equivalent K(1)Cl7 pentagonal bipyramids, and edges with four equivalent K(2)Cl7 pentagonal bipyramids. There are three inequivalent Cl sites. In the first Cl site, Cl(1) is bonded to three equivalent K(1) and two equivalent Hg(1) atoms to form ClK3Hg2 trigonal bipyramids that share corners with four equivalent Cl(1)K3Hg2 trigonal bipyramids, corners with four equivalent Cl(2)K3Hg2 trigonal bipyramids, corners with four equivalent Cl(3)K4Hg trigonal bipyramids, edges with two equivalent Cl(1)K3Hg2 trigonal bipyramids, and edges with six equivalent Cl(3)K4Hg trigonal bipyramids. In the second Cl site, Cl(2) is bonded to three equivalent K(2) and two equivalent Hg(1) atoms to form ClK3Hg2 trigonal bipyramids that share corners with four equivalent Cl(1)K3Hg2 trigonal bipyramids, corners with four equivalent Cl(2)K3Hg2 trigonal bipyramids, corners with four equivalent Cl(3)K4Hg trigonal bipyramids, edges with two equivalent Cl(2)K3Hg2 trigonal bipyramids, and edges with six equivalent Cl(3)K4Hg trigonal bipyramids. In the third Cl site, Cl(3) is bonded to two equivalent K(1), two equivalent K(2), and one Hg(1) atom to form distorted ClK4Hg trigonal bipyramids that share corners with two equivalent Cl(1)K3Hg2 trigonal bipyramids, corners with two equivalent Cl(2)K3Hg2 trigonal bipyramids, corners with five equivalent Cl(3)K4Hg trigonal bipyramids, edges with three equivalent Cl(1)K3Hg2 trigonal bipyramids, edges with three equivalent Cl(2)K3Hg2 trigonal bipyramids, and edges with four equivalent Cl(3)K4Hg trigonal bipyramids. is represented by the CIF file [CIF]
data_K2HgCl4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.450
_cell_length_b   7.763
_cell_length_c   11.848
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   409.332
_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
  Cl  Cl0  1  0.000  0.728  0.559  1.0
  Cl  Cl1  1  0.000  0.272  0.441  1.0
  Cl  Cl2  1  0.000  0.228  0.941  1.0
  Cl  Cl3  1  0.000  0.772  0.059  1.0
  Cl  Cl4  1  0.500  0.380  0.693  1.0
  Cl  Cl5  1  0.500  0.620  0.307  1.0
  Cl  Cl6  1  0.500  0.880  0.807  1.0
  Cl  Cl7  1  0.500  0.120  0.193  1.0
  Hg  Hg8  1  0.500  0.500  0.500  1.0
  Hg  Hg9  1  0.500  0.000  1.000  1.0
  K  K10  1  0.000  0.093  0.680  1.0
  K  K11  1  0.000  0.907  0.320  1.0
  K  K12  1  0.000  0.593  0.820  1.0
  K  K13  1  0.000  0.407  0.180  1.0
[/CIF]
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The compound described by K2HgCl4 crystallizes in the orthorhombic Pbam space group. There are two inequivalent K sites. In the first K site, K(1) is bonded to three equivalent Cl(1) and four equivalent Cl(3) atoms to form distorted KCl7 pentagonal bipyramids that share corners with two equivalent Hg(1)Cl6 octahedra, corners with two equivalent K(1)Cl7 pentagonal bipyramids, corners with four equivalent K(2)Cl7 pentagonal bipyramids, edges with four equivalent Hg(1)Cl6 octahedra,  an edgeedge with one K(1)Cl7 pentagonal bipyramid, edges with two equivalent K(2)Cl7 pentagonal bipyramids, and faces with two equivalent K(1)Cl7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 50°. In the second K site, K(2) is bonded to three equivalent Cl(2) and four equivalent Cl(3) atoms to form distorted KCl7 pentagonal bipyramids that share corners with two equivalent Hg(1)Cl6 octahedra, corners with two equivalent K(2)Cl7 pentagonal bipyramids, corners with four equivalent K(1)Cl7 pentagonal bipyramids, edges with four equivalent Hg(1)Cl6 octahedra,  an edgeedge with one K(2)Cl7 pentagonal bipyramid, edges with two equivalent K(1)Cl7 pentagonal bipyramids, and faces with two equivalent K(2)Cl7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 50°. Hg(1) is bonded to two equivalent Cl(1), two equivalent Cl(2), and two equivalent Cl(3) atoms to form HgCl6 octahedra that share corners with two equivalent K(1)Cl7 pentagonal bipyramids, corners with two equivalent K(2)Cl7 pentagonal bipyramids, edges with two equivalent Hg(1)Cl6 octahedra, edges with four equivalent K(1)Cl7 pentagonal bipyramids, and edges with four equivalent K(2)Cl7 pentagonal bipyramids. There are three inequivalent Cl sites. In the first Cl site, Cl(1) is bonded to three equivalent K(1) and two equivalent Hg(1) atoms to form ClK3Hg2 trigonal bipyramids that share corners with four equivalent Cl(1)K3Hg2 trigonal bipyramids, corners with four equivalent Cl(2)K3Hg2 trigonal bipyramids, corners with four equivalent Cl(3)K4Hg trigonal bipyramids, edges with two equivalent Cl(1)K3Hg2 trigonal bipyramids, and edges with six equivalent Cl(3)K4Hg trigonal bipyramids. In the second Cl site, Cl(2) is bonded to three equivalent K(2) and two equivalent Hg(1) atoms to form ClK3Hg2 trigonal bipyramids that share corners with four equivalent Cl(1)K3Hg2 trigonal bipyramids, corners with four equivalent Cl(2)K3Hg2 trigonal bipyramids, corners with four equivalent Cl(3)K4Hg trigonal bipyramids, edges with two equivalent Cl(2)K3Hg2 trigonal bipyramids, and edges with six equivalent Cl(3)K4Hg trigonal bipyramids. In the third Cl site, Cl(3) is bonded to two equivalent K(1), two equivalent K(2), and one Hg(1) atom to form distorted ClK4Hg trigonal bipyramids that share corners with two equivalent Cl(1)K3Hg2 trigonal bipyramids, corners with two equivalent Cl(2)K3Hg2 trigonal bipyramids, corners with five equivalent Cl(3)K4Hg trigonal bipyramids, edges with three equivalent Cl(1)K3Hg2 trigonal bipyramids, edges with three equivalent Cl(2)K3Hg2 trigonal bipyramids, and edges with four equivalent Cl(3)K4Hg trigonal bipyramids. is represented by the CIF file [CIF]
data_K2HgCl4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.450
_cell_length_b   7.763
_cell_length_c   11.848
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   409.332
_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
  Cl  Cl0  1  0.000  0.728  0.559  1.0
  Cl  Cl1  1  0.000  0.272  0.441  1.0
  Cl  Cl2  1  0.000  0.228  0.941  1.0
  Cl  Cl3  1  0.000  0.772  0.059  1.0
  Cl  Cl4  1  0.500  0.380  0.693  1.0
  Cl  Cl5  1  0.500  0.620  0.307  1.0
  Cl  Cl6  1  0.500  0.880  0.807  1.0
  Cl  Cl7  1  0.500  0.120  0.193  1.0
  Hg  Hg8  1  0.500  0.500  0.500  1.0
  Hg  Hg9  1  0.500  0.000  1.000  1.0
  K  K10  1  0.000  0.093  0.680  1.0
  K  K11  1  0.000  0.907  0.320  1.0
  K  K12  1  0.000  0.593  0.820  1.0
  K  K13  1  0.000  0.407  0.180  1.0
[/CIF]
.