Evolution of the α-BaMg(CO<sub>3</sub>)<sub>2</sub> low-temperature superstructure and the tricritical nature of its α-β phase transition.
Ende, Martin; Effenberger, Herta; Miletich, Ronald; Acta crystallographica Section B, Structural science, crystal engineering and materials 73 (2017) 827–835; doi:10.1107/S2052520617009295

data_2311743
_publ_section_title
;
 Evolution of the \a-BaMg(CO<sub>3</sub>)<sub>2</sub> low-temperature
 superstructure and the tricritical nature of its \a-\b phase transition.
;
_journal_issue                   'Pt 5'
_journal_name_full
'Acta crystallographica Section B, Structural science, crystal engineering and materials'
_journal_page_first              827
_journal_page_last               835
_journal_paper_doi               10.1107/S2052520617009295
_journal_volume                  73
_journal_year                    2017
_chemical_formula_sum            'C6 Ba3 Mg3 O18'
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_cell_measurement_temperature    150(2)
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_computing_structure_refinement  'SHELXL-2014/7 (Sheldrick, 2014)'
_diffrn_ambient_temperature      150(2)
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_diffrn_measurement_device_type  StoeStadiVari
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0300
_diffrn_reflns_av_unetI/netI     0.0141
_diffrn_reflns_Laue_measured_fraction_full 0.993
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_diffrn_reflns_limit_h_max       9
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_diffrn_reflns_point_group_measured_fraction_full 0.993
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_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         45.588
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_exptl_absorpt_coefficient_mu    8.298
_exptl_absorpt_correction_T_max  0.8
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_exptl_absorpt_correction_type   numerical
_exptl_absorpt_process_details   '(Stoe & Cie GmbH 2016)'
_exptl_crystal_density_diffrn    3.869
_exptl_crystal_description       prismatic
_exptl_crystal_F_000             768
_exptl_crystal_size_max          0.060
_exptl_crystal_size_mid          0.030
_exptl_crystal_size_min          0.030
_refine_diff_density_max         0.418
_refine_diff_density_min         -0.580
_refine_diff_density_rms         0.125
_refine_ls_extinction_method     none
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_refine_ls_hydrogen_treatment    undef
_refine_ls_matrix_type           full
_refine_ls_number_parameters     17
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_refine_ls_restrained_S_all      1.019
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_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0096P)^2^] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
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_refine_ls_wR_factor_ref         0.0196
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_reflns_number_gt                506
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_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            xk5041sup1.cif
_cod_data_source_block           norse_150
_cod_original_cell_volume        725.43(7)
_cod_original_sg_symbol_H-M      'R -3 c'
_cod_database_code               2311743
_shelx_shelxl_version_number     2014/7
_shelx_estimated_absorpt_t_min   0.636
_shelx_estimated_absorpt_t_max   0.789
_shelx_res_checksum              21797
_shelx_hkl_checksum              10071