A Cu2+ (S = 1/2) Kagomé Antiferromagnet: MgxCu4-x(OH)6Cl2
Shaoyan Chu; Tyrel M. McQueen; Robin Chisnell; Danna E. Freedman; Peter Müller; Young S. Lee; Daniel G. Nocera; Journal of the American Chemical Society 132 (2010) 5570–5571; doi:10.1021/ja1008322

data_4102325
_publ_section_title
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 A Cu2+ (S = 1/2) Kagom\'e Antiferromagnet: MgxCu4-x(OH)6Cl2
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_journal_name_full               'Journal of the American Chemical Society'
_journal_page_first              5570
_journal_page_last               5571
_journal_paper_doi               10.1021/ja1008322
_journal_volume                  132
_journal_year                    2010
_chemical_formula_sum            'Cl2 Cu3.67 H6 Mg0.33 O6'
_chemical_formula_weight         414.29
_chemical_name_systematic
; 
 ? 
;
_space_group_IT_number           166
_symmetry_cell_setting           rhombohedral
_symmetry_space_group_name_Hall  '-R 3 2"'
_symmetry_space_group_name_H-M   'R -3 m :H'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_cell_angle_alpha                90.00
_cell_angle_beta                 90.00
_cell_angle_gamma                120.00
_cell_formula_units_Z            3
_cell_length_a                   6.8393(18)
_cell_length_b                   6.8393(18)
_cell_length_c                   14.005(4)
_cell_measurement_reflns_used    2009
_cell_measurement_temperature    100(2)
_cell_measurement_theta_max      30.50
_cell_measurement_theta_min      3.73
_cell_volume                     567.3(3)
_computing_cell_refinement       'SAINT 7.46A (Bruker-AXS, 2009)'
_computing_data_collection       'APEX2 v2009.9.0 (Bruker-AXS, 2009)'
_computing_data_reduction        'SAINT 7.46A (Bruker-AXS, 2009)'
_computing_molecular_graphics    'Bruker SHELXTL'
_computing_publication_material  'Bruker SHELXTL'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 2008)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      100(2)
_diffrn_detector_area_resol_mean 8.3
_diffrn_measured_fraction_theta_full 0.991
_diffrn_measured_fraction_theta_max 0.991
_diffrn_measurement_device_type  'Bruker Smart APEX CCD'
_diffrn_measurement_method       '\f and \w 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  0.0414
_diffrn_reflns_av_sigmaI/netI    0.0181
_diffrn_reflns_limit_h_max       9
_diffrn_reflns_limit_h_min       -9
_diffrn_reflns_limit_k_max       9
_diffrn_reflns_limit_k_min       -9
_diffrn_reflns_limit_l_max       19
_diffrn_reflns_limit_l_min       -19
_diffrn_reflns_number            2585
_diffrn_reflns_theta_full        29.47
_diffrn_reflns_theta_max         29.47
_diffrn_reflns_theta_min         3.74
_exptl_absorpt_coefficient_mu    10.913
_exptl_absorpt_correction_T_max  0.2914
_exptl_absorpt_correction_T_min  0.2584
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'SADABS (Sheldrick, 2009)'
_exptl_crystal_colour            blue
_exptl_crystal_density_diffrn    3.638
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       octahedron
_exptl_crystal_F_000             595
_exptl_crystal_size_max          0.17
_exptl_crystal_size_mid          0.16
_exptl_crystal_size_min          0.15
_refine_diff_density_max         0.917
_refine_diff_density_min         -1.071
_refine_diff_density_rms         0.145
_refine_ls_extinction_coef       0.0058(7)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     SHELXL
_refine_ls_goodness_of_fit_ref   1.244
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     21
_refine_ls_number_reflns         223
_refine_ls_number_restraints     2
_refine_ls_restrained_S_all      1.244
_refine_ls_R_factor_all          0.0221
_refine_ls_R_factor_gt           0.0219
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0193P)^2^+6.2183P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0555
_refine_ls_wR_factor_ref         0.0556
_reflns_number_gt                221
_reflns_number_total             223
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ja1008322_si_002.cif
_cod_data_source_block           09324
_cod_original_sg_symbol_H-M      'R -3 m'
_cod_original_formula_sum        'H6 Cl2 Cu3.67 Mg0.33 O6'
_cod_database_code               4102325