data_2103470
_publ_section_title
;
 The structure of orange HgI₂. I. Polytypic layer structure
;
_journal_issue                   6
_journal_name_full               'Acta Crystallographica Section B'
_journal_page_first              903
_journal_page_last               913
_journal_paper_doi               10.1107/S010876810201618X
_journal_volume                  58
_journal_year                    2002
_chemical_formula_moiety         HgI2
_chemical_formula_sum            'Hg I2'
_chemical_formula_weight         454.39
_chemical_melting_point          529
_chemical_name_common            'mercuric iodide'
_chemical_name_systematic
;
 ?
;
_space_group_IT_number           137
_symmetry_cell_setting           tetragonal
_symmetry_space_group_name_Hall  '-P 4ac 2a'
_symmetry_space_group_name_H-M   'P 42/n m c :2'
_atom_sites_solution_hydrogens   none
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_cell_angle_alpha                90.00
_cell_angle_beta                 90.00
_cell_angle_gamma                90.00
_cell_formula_units_Z            8
_cell_length_a                   8.7863(5)
_cell_length_b                   8.7863(5)
_cell_length_c                   12.334(3)
_cell_measurement_reflns_used    618
_cell_measurement_temperature    200.0(10)
_cell_measurement_theta_max      24.11
_cell_measurement_theta_min      14.28
_cell_volume                     952.2(2)
_computing_cell_refinement       'Kuma CrysAlis'
_computing_data_collection       'Kuma CrysAlis'
_computing_data_reduction        'Kuma CrysAlis'
_computing_molecular_graphics    Cerius2
_computing_publication_material  'Cerius2, Bruker Shelxtl'
_computing_structure_refinement  'STACK (Birkedal et al., 1998)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      200.0(10)
_diffrn_detector_area_resol_mean 17.07
_diffrn_measured_fraction_theta_full 0.990
_diffrn_measured_fraction_theta_max 0.990
_diffrn_measurement_device_type  'Kuma CCD'
_diffrn_measurement_method       'ω scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0730
_diffrn_reflns_av_sigmaI/netI    0.0084
_diffrn_reflns_limit_h_max       7
_diffrn_reflns_limit_h_min       0
_diffrn_reflns_limit_k_max       10
_diffrn_reflns_limit_k_min       0
_diffrn_reflns_limit_l_max       30
_diffrn_reflns_limit_l_min       0
_diffrn_reflns_number            843
_diffrn_reflns_theta_full        26.38
_diffrn_reflns_theta_max         26.58
_diffrn_reflns_theta_min         3.67
_exptl_absorpt_coefficient_mu    45.090
_exptl_absorpt_correction_T_max  0.411
_exptl_absorpt_correction_T_min  0.017
_exptl_absorpt_correction_type   analytical
_exptl_absorpt_process_details   'based on the shape of the crystal'
_exptl_crystal_colour            orange
_exptl_crystal_density_diffrn    6.340
_exptl_crystal_density_meas      ?
_exptl_crystal_density_method    .
_exptl_crystal_description       'truncated pyramid'
_exptl_crystal_F_000             1488
_exptl_crystal_size_max          0.10
_exptl_crystal_size_mid          0.10
_exptl_crystal_size_min          0.02
_refine_diff_density_max         'not computed with STACK'
_refine_diff_density_min         'not computed with STACK'
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.066
_refine_ls_hydrogen_treatment    none
_refine_ls_matrix_type           full
_refine_ls_number_parameters     20
_refine_ls_number_reflns         570
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.066
_refine_ls_R_factor_all          0.066
_refine_ls_R_factor_gt           0.066
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef F
_refine_ls_weighting_details
'calc w=1/[σ²(Yo²)+(0.03030P)²+4.60896P] where P=(Yo+2Yc)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.133
_refine_ls_wR_factor_ref         0.133
_reflns_number_gt                570
_reflns_number_total             570
_reflns_threshold_expression     >2sigma(I)
_[local]_cod_data_source_file    bk0119.cif
_[local]_cod_data_source_block   II
_[local]_cod_cif_authors_sg_H-M  P42/nmc
_cod_database_code               2103470
loop_
_symmetry_equiv_pos_as_xyz
'x, y, z'
'-x+1/2, -y+1/2, z'
'-y+1/2, x, z+1/2'
'y, -x+1/2, z+1/2'
'-x, y+1/2, -z'
'x+1/2, -y, -z'
'y+1/2, x+1/2, -z+1/2'
'-y, -x, -z+1/2'
'-x, -y, -z'
'x-1/2, y-1/2, -z'
'y-1/2, -x, -z-1/2'
'-y, x-1/2, -z-1/2'
'x, -y-1/2, z'
'-x-1/2, y, z'
'-y-1/2, -x-1/2, z-1/2'
'y, x, z-1/2'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_U_iso_or_equiv
_atom_site_adp_type
_atom_site_calc_flag
_atom_site_refinement_flags
_atom_site_occupancy
_atom_site_type_symbol
Hg 0.50043(19) 0.75 0.12481(13) 0.0399(5) Uani d P 1 Hg
I1 0.25 0.25 0.5165(3) 0.0343(10) Uani d P 1 I
I2 0.51381(17) 0.01381(17) 0.25 0.0292(4) Uani d P 1 I
I3 0.25 0.75 0.5136(3) 0.0316(9) Uani d P 1 I
loop_
_atom_site_aniso_label
_atom_site_aniso_U_11
_atom_site_aniso_U_22
_atom_site_aniso_U_33
_atom_site_aniso_U_12
_atom_site_aniso_U_13
_atom_site_aniso_U_23
Hg 0.0367(7) 0.0446(7) 0.0385(11) 0.0 -0.0008(3) 0.0
I1 0.058(2) 0.0146(13) 0.0301(14) 0.0 0.0 0.0
I2 0.0302(7) 0.0302(7) 0.0272(8) -0.0029(5) 0.0008(3) -0.0008(3)
I3 0.0454(18) 0.0282(16) 0.0211(14) 0.0 0.0 0.0
loop_
_atom_type_symbol
_atom_type_description
_atom_type_scat_dispersion_real
_atom_type_scat_dispersion_imag
_atom_type_scat_source
I I -0.4742 1.8119 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4'
Hg Hg -2.3894 9.2266 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4'
