The material described by Hg4SiSe6 crystallizes in the monoclinic Cc space group. There are four inequivalent Hg sites. In the first Hg site, Hg(1) is bonded to one Se(1), one Se(2), one Se(5), and one Se(6) atom to form HgSe4 trigonal pyramids that share corners with two equivalent Hg(4)Se4 tetrahedra, corners with two equivalent Si(1)Se4 tetrahedra, corners with three equivalent Hg(2)Se4 tetrahedra, and corners with three equivalent Hg(3)Se4 tetrahedra. In the second Hg site, Hg(2) is bonded to one Se(1), one Se(2), one Se(4), and one Se(5) atom to form HgSe4 tetrahedra that share corners with two equivalent Hg(3)Se4 tetrahedra, corners with two equivalent Si(1)Se4 tetrahedra, corners with three equivalent Hg(4)Se4 tetrahedra, and corners with three equivalent Hg(1)Se4 trigonal pyramids. In the third Hg site, Hg(3) is bonded to one Se(1), one Se(3), one Se(5), and one Se(6) atom to form HgSe4 tetrahedra that share corners with two equivalent Hg(2)Se4 tetrahedra, corners with two equivalent Si(1)Se4 tetrahedra, corners with three equivalent Hg(4)Se4 tetrahedra, and corners with three equivalent Hg(1)Se4 trigonal pyramids. In the fourth Hg site, Hg(4) is bonded to one Se(1), one Se(3), one Se(4), and one Se(5) atom to form HgSe4 tetrahedra that share corners with two equivalent Si(1)Se4 tetrahedra, corners with three equivalent Hg(2)Se4 tetrahedra, corners with three equivalent Hg(3)Se4 tetrahedra, and corners with two equivalent Hg(1)Se4 trigonal pyramids. Si(1) is bonded to one Se(2), one Se(3), one Se(4), and one Se(6) atom to form SiSe4 tetrahedra that share corners with two equivalent Hg(2)Se4 tetrahedra, corners with two equivalent Hg(3)Se4 tetrahedra, corners with two equivalent Hg(4)Se4 tetrahedra, and corners with two equivalent Hg(1)Se4 trigonal pyramids. There are six inequivalent Se sites. In the first Se site, Se(1) is bonded to one Hg(1), one Hg(2), one Hg(3), and one Hg(4) atom to form corner-sharing SeHg4 trigonal pyramids. In the second Se site, Se(2) is bonded in a trigonal non-coplanar geometry to one Hg(1), one Hg(2), and one Si(1) atom. In the third Se site, Se(3) is bonded in a trigonal non-coplanar geometry to one Hg(3), one Hg(4), and one Si(1) atom. In the fourth Se site, Se(4) is bonded in a trigonal non-coplanar geometry to one Hg(2), one Hg(4), and one Si(1) atom. In the fifth Se site, Se(5) is bonded to one Hg(1), one Hg(2), one Hg(3), and one Hg(4) atom to form corner-sharing SeHg4 tetrahedra. In the sixth Se site, Se(6) is bonded in a distorted trigonal non-coplanar geometry to one Hg(1), one Hg(3), and one Si(1) atom. is represented by the CIF file [CIF]
data_Si(Hg2Se3)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.632
_cell_length_b   7.632
_cell_length_c   13.184
_cell_angle_alpha   72.713
_cell_angle_beta   72.713
_cell_angle_gamma   59.922
_symmetry_Int_Tables_number   1
_cell_volume   624.293
_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
  Si  Si0  1  0.678  0.140  0.397  1.0
  Si  Si1  1  0.140  0.678  0.897  1.0
  Hg  Hg2  1  0.275  0.674  0.309  1.0
  Hg  Hg3  1  0.674  0.275  0.809  1.0
  Hg  Hg4  1  0.796  0.898  0.155  1.0
  Hg  Hg5  1  0.898  0.796  0.655  1.0
  Hg  Hg6  1  0.547  0.773  0.958  1.0
  Hg  Hg7  1  0.773  0.547  0.458  1.0
  Hg  Hg8  1  0.082  0.271  0.142  1.0
  Hg  Hg9  1  0.271  0.082  0.642  1.0
  Se  Se10  1  0.543  0.031  0.768  1.0
  Se  Se11  1  0.031  0.543  0.268  1.0
  Se  Se12  1  0.992  0.971  0.447  1.0
  Se  Se13  1  0.971  0.992  0.947  1.0
  Se  Se14  1  0.970  0.481  0.945  1.0
  Se  Se15  1  0.481  0.970  0.445  1.0
  Se  Se16  1  0.708  0.251  0.213  1.0
  Se  Se17  1  0.251  0.708  0.713  1.0
  Se  Se18  1  0.423  0.909  0.148  1.0
  Se  Se19  1  0.909  0.423  0.648  1.0
  Se  Se20  1  0.479  0.429  0.477  1.0
  Se  Se21  1  0.429  0.479  0.977  1.0
[/CIF]
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The material described by Hg4SiSe6 crystallizes in the monoclinic Cc space group. There are four inequivalent Hg sites. In the first Hg site, Hg(1) is bonded to one Se(1), one Se(2), one Se(5), and one Se(6) atom to form HgSe4 trigonal pyramids that share corners with two equivalent Hg(4)Se4 tetrahedra, corners with two equivalent Si(1)Se4 tetrahedra, corners with three equivalent Hg(2)Se4 tetrahedra, and corners with three equivalent Hg(3)Se4 tetrahedra. In the second Hg site, Hg(2) is bonded to one Se(1), one Se(2), one Se(4), and one Se(5) atom to form HgSe4 tetrahedra that share corners with two equivalent Hg(3)Se4 tetrahedra, corners with two equivalent Si(1)Se4 tetrahedra, corners with three equivalent Hg(4)Se4 tetrahedra, and corners with three equivalent Hg(1)Se4 trigonal pyramids. In the third Hg site, Hg(3) is bonded to one Se(1), one Se(3), one Se(5), and one Se(6) atom to form HgSe4 tetrahedra that share corners with two equivalent Hg(2)Se4 tetrahedra, corners with two equivalent Si(1)Se4 tetrahedra, corners with three equivalent Hg(4)Se4 tetrahedra, and corners with three equivalent Hg(1)Se4 trigonal pyramids. In the fourth Hg site, Hg(4) is bonded to one Se(1), one Se(3), one Se(4), and one Se(5) atom to form HgSe4 tetrahedra that share corners with two equivalent Si(1)Se4 tetrahedra, corners with three equivalent Hg(2)Se4 tetrahedra, corners with three equivalent Hg(3)Se4 tetrahedra, and corners with two equivalent Hg(1)Se4 trigonal pyramids. Si(1) is bonded to one Se(2), one Se(3), one Se(4), and one Se(6) atom to form SiSe4 tetrahedra that share corners with two equivalent Hg(2)Se4 tetrahedra, corners with two equivalent Hg(3)Se4 tetrahedra, corners with two equivalent Hg(4)Se4 tetrahedra, and corners with two equivalent Hg(1)Se4 trigonal pyramids. There are six inequivalent Se sites. In the first Se site, Se(1) is bonded to one Hg(1), one Hg(2), one Hg(3), and one Hg(4) atom to form corner-sharing SeHg4 trigonal pyramids. In the second Se site, Se(2) is bonded in a trigonal non-coplanar geometry to one Hg(1), one Hg(2), and one Si(1) atom. In the third Se site, Se(3) is bonded in a trigonal non-coplanar geometry to one Hg(3), one Hg(4), and one Si(1) atom. In the fourth Se site, Se(4) is bonded in a trigonal non-coplanar geometry to one Hg(2), one Hg(4), and one Si(1) atom. In the fifth Se site, Se(5) is bonded to one Hg(1), one Hg(2), one Hg(3), and one Hg(4) atom to form corner-sharing SeHg4 tetrahedra. In the sixth Se site, Se(6) is bonded in a distorted trigonal non-coplanar geometry to one Hg(1), one Hg(3), and one Si(1) atom. is represented by the CIF file [CIF]
data_Si(Hg2Se3)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.632
_cell_length_b   7.632
_cell_length_c   13.184
_cell_angle_alpha   72.713
_cell_angle_beta   72.713
_cell_angle_gamma   59.922
_symmetry_Int_Tables_number   1
_cell_volume   624.293
_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
  Si  Si0  1  0.678  0.140  0.397  1.0
  Si  Si1  1  0.140  0.678  0.897  1.0
  Hg  Hg2  1  0.275  0.674  0.309  1.0
  Hg  Hg3  1  0.674  0.275  0.809  1.0
  Hg  Hg4  1  0.796  0.898  0.155  1.0
  Hg  Hg5  1  0.898  0.796  0.655  1.0
  Hg  Hg6  1  0.547  0.773  0.958  1.0
  Hg  Hg7  1  0.773  0.547  0.458  1.0
  Hg  Hg8  1  0.082  0.271  0.142  1.0
  Hg  Hg9  1  0.271  0.082  0.642  1.0
  Se  Se10  1  0.543  0.031  0.768  1.0
  Se  Se11  1  0.031  0.543  0.268  1.0
  Se  Se12  1  0.992  0.971  0.447  1.0
  Se  Se13  1  0.971  0.992  0.947  1.0
  Se  Se14  1  0.970  0.481  0.945  1.0
  Se  Se15  1  0.481  0.970  0.445  1.0
  Se  Se16  1  0.708  0.251  0.213  1.0
  Se  Se17  1  0.251  0.708  0.713  1.0
  Se  Se18  1  0.423  0.909  0.148  1.0
  Se  Se19  1  0.909  0.423  0.648  1.0
  Se  Se20  1  0.479  0.429  0.477  1.0
  Se  Se21  1  0.429  0.479  0.977  1.0
[/CIF]
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