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_2311745
_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    250(2)
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_computing_structure_refinement  'SHELXL-2014/7 (Sheldrick, 2014)'
_diffrn_ambient_temperature      250(2)
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_diffrn_measurement_device_type  StoeStadiVari
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_diffrn_reflns_Laue_measured_fraction_full 0.993
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_diffrn_reflns_point_group_measured_fraction_full 0.993
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_exptl_absorpt_coefficient_mu    8.260
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_exptl_absorpt_correction_type   numerical
_exptl_absorpt_process_details   '(Stoe & Cie GmbH 2016)'
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_exptl_crystal_description       prismatic
_exptl_crystal_F_000             768
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_exptl_crystal_size_mid          0.030
_exptl_crystal_size_min          0.030
_refine_diff_density_max         0.432
_refine_diff_density_min         -0.599
_refine_diff_density_rms         0.107
_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      0.947
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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^)+(0.0112P)^2^] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
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_refine_ls_wR_factor_ref         0.0207
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_reflns_number_total             697
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            xk5041sup1.cif
_cod_data_source_block           norse_250
_cod_original_cell_volume        728.75(4)
_cod_original_sg_symbol_H-M      'R -3 c'
_cod_database_code               2311745
_shelx_shelxl_version_number     2014/7
_shelx_estimated_absorpt_t_min   0.637
_shelx_estimated_absorpt_t_max   0.790
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_shelx_hkl_checksum              42528