Crystallization of metastable monoclinic carnallite, KCl·MgCl~2~·6H~2~O: missing structural link in the carnallite family
Pannach, Melanie; Paschke, Iris; Schmidt, Horst; Freyer, Daniela; Voigt, Wolfgang; Acta Crystallographica Section C 76 (2020) 507–512; doi:10.1107/S2053229620005197

data_2022100
_publ_section_title
;
 Crystallization of metastable monoclinic carnallite,
 KCl&#x00B7;MgCl~2~&#x00B7;6H~2~O: missing structural link in the
 carnallite family
;
_journal_coeditor_code           UK3195
_journal_issue                   5
_journal_name_full               'Acta Crystallographica Section C'
_journal_page_first              507
_journal_page_last               512
_journal_paper_doi               10.1107/S2053229620005197
_journal_volume                  76
_journal_year                    2020
_chemical_formula_iupac          'K Cl, Mg Cl2, 6H2 O'
_chemical_formula_moiety         'H12 Mg O6, 3(Cl), K'
_chemical_formula_sum            'Cl3 H12 K Mg O6'
_chemical_formula_weight         277.86
_chemical_name_common            'potassium carnallite'
_chemical_name_systematic
'Potassium chloride magnesium dichloride hexahydrate'
_space_group_crystal_system      monoclinic
_space_group_IT_number           15
_space_group_name_Hall           '-C 2yc'
_space_group_name_H-M_alt        'C 1 2/c 1'
_atom_sites_solution_hydrogens   difmap
_audit_creation_method           SHELXL-2016/6
_cell_angle_alpha                90
_cell_angle_beta                 90.06(2)
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   9.251(2)
_cell_length_b                   9.516(2)
_cell_length_c                   13.217(4)
_cell_measurement_reflns_used    3875
_cell_measurement_temperature    200
_cell_measurement_theta_max      27.39
_cell_measurement_theta_min      3.11
_cell_volume                     1163.5(5)
_computing_cell_refinement
;
X-AREA (Stoe & Cie, 2002)
;
_computing_data_collection
;
X-AREA (Stoe & Cie, 2002)
;
_computing_data_reduction
;
X-RED32 (Stoe & Cie, 2002)
;
_computing_molecular_graphics    '<b>Please provide program name</b>'
_computing_publication_material
;
SHELXL2016 (Sheldrick, 2015b)
;
_computing_structure_refinement
;
SHELXL2016 (Sheldrick, 2015b)
;
_computing_structure_solution
;
SHELXT (Sheldrick, 2015a)
;
_diffrn_ambient_temperature      200
_diffrn_detector                 'image plate (34 cm diameter)'
_diffrn_detector_area_resol_mean 6.67
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 0.999
_diffrn_measurement_device       '2-circle goniometer'
_diffrn_measurement_device_type  'Stoe IPDS 2T'
_diffrn_measurement_method       'rotation method'
_diffrn_radiation_monochromator  'plane graphite'
_diffrn_radiation_type           'Mo K\a'
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0458
_diffrn_reflns_av_unetI/netI     0.0146
_diffrn_reflns_limit_h_max       11
_diffrn_reflns_limit_h_min       -12
_diffrn_reflns_limit_k_max       12
_diffrn_reflns_limit_k_min       -12
_diffrn_reflns_limit_l_max       17
_diffrn_reflns_limit_l_min       -17
_diffrn_reflns_number            1341
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         27.499
_diffrn_reflns_theta_min         3.071
_diffrn_source
'sealed X-ray tube, 12 x 0.4 mm long-fine focus'
_diffrn_source_current           40
_diffrn_source_power             2.000
_diffrn_source_voltage           50
_exptl_absorpt_coefficient_mu    1.186
_exptl_absorpt_correction_T_max  0.9830
_exptl_absorpt_correction_T_min  0.6654
_exptl_absorpt_correction_type   integration
_exptl_absorpt_process_details
;
Coppens (1970)
;
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.586
_exptl_crystal_description       'square planar crystals'
_exptl_crystal_F_000             568
_exptl_crystal_size_max          0.3
_exptl_crystal_size_mid          0.26
_exptl_crystal_size_min          0.06
_refine_diff_density_max         0.253
_refine_diff_density_min         -0.492
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.206
_refine_ls_hydrogen_treatment    refall
_refine_ls_matrix_type           full
_refine_ls_number_parameters     78
_refine_ls_number_reflns         1341
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.206
_refine_ls_R_factor_all          0.0450
_refine_ls_R_factor_gt           0.0347
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0379P)^2^+1.1854P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0882
_refine_ls_wR_factor_ref         0.0961
_reflns_number_gt                1096
_reflns_number_total             1341
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            uk3195sup1.cif
_cod_data_source_block           I
_cod_original_cell_volume        1163.6(5)
_cod_original_sg_symbol_H-M      'C 2/c'
_cod_database_code               2022100
_shelx_hkl_checksum              4283
_shelx_res_checksum              94800
_cod_database_fobs_code 2022100