Redetermination of Mg~2~B~25~ based on single-crystal X-ray data
Bindi, Luca; Figini Albisetti, Alessandro; Giunchi, Giovanni; Malpezzi, Luciana; Masciocchi, Norberto; Acta Crystallographica Section E 68 (2012) i50–; doi:10.1107/S1600536812023768

data_2235288
_publ_section_title
;
 Redetermination of Mg~2~B~25~ based on single-crystal X-ray data
;
_journal_coeditor_code           WM2631
_journal_issue                   6
_journal_name_full               'Acta Crystallographica Section E'
_journal_page_first              i50
_journal_paper_doi               10.1107/S1600536812023768
_journal_volume                  68
_journal_year                    2012
_chemical_formula_iupac          'Mg2 B25'
_chemical_formula_moiety         'Mg2 B25'
_chemical_formula_sum            'B25 Mg2'
_chemical_formula_weight         318.87
_chemical_name_systematic
;
dimagnesium pentaeicosaboride
;
_space_group_IT_number           166
_symmetry_cell_setting           hexagonal
_symmetry_space_group_name_Hall  '-R 3 2"'
_symmetry_space_group_name_H-M   'R -3 m :H'
_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            12
_cell_length_a                   11.0398(5)
_cell_length_b                   11.0398(5)
_cell_length_c                   24.1950(10)
_cell_measurement_reflns_used    562
_cell_measurement_temperature    298(2)
_cell_measurement_theta_max      26.2
_cell_measurement_theta_min      10.6
_cell_volume                     2553.75(19)
_computing_cell_refinement
'<i>CrysAlis CCD</i> (Oxford Diffraction, 2006)'
_computing_data_collection
'<i>CrysAlis CCD</i> (Oxford Diffraction, 2006)'
_computing_data_reduction
'<i>CrysAlis RED</i> (Oxford Diffraction, 2006)'
_computing_molecular_graphics    'DIAMOND (Brandenburg, 2001)'
_computing_publication_material  'SHELXL97 (Sheldrick, 2008)'
_computing_structure_refinement  'SHELXL97 (Sheldrick, 2008)'
_computing_structure_solution    'SHELXS97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      298(2)
_diffrn_measured_fraction_theta_full 0.998
_diffrn_measured_fraction_theta_max 0.998
_diffrn_measurement_device_type  'Oxford Xcalibur 3 CCD'
_diffrn_measurement_method       '\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  0.0451
_diffrn_reflns_av_sigmaI/netI    0.0237
_diffrn_reflns_limit_h_max       14
_diffrn_reflns_limit_h_min       -14
_diffrn_reflns_limit_k_max       14
_diffrn_reflns_limit_k_min       -14
_diffrn_reflns_limit_l_max       31
_diffrn_reflns_limit_l_min       -31
_diffrn_reflns_number            4794
_diffrn_reflns_theta_full        28.00
_diffrn_reflns_theta_max         28.00
_diffrn_reflns_theta_min         2.29
_exptl_absorpt_coefficient_mu    0.233
_exptl_absorpt_correction_T_max  0.984
_exptl_absorpt_correction_T_min  0.982
_exptl_absorpt_correction_type   gaussian
_exptl_absorpt_process_details   '(<i>ABSPACK</i>; Oxford Diffraction, 2006)'
_exptl_crystal_colour            black
_exptl_crystal_density_diffrn    2.488
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             1788
_exptl_crystal_size_max          0.075
_exptl_crystal_size_mid          0.070
_exptl_crystal_size_min          0.065
_refine_diff_density_max         0.142
_refine_diff_density_min         -0.312
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.131
_refine_ls_matrix_type           full
_refine_ls_number_parameters     122
_refine_ls_number_reflns         799
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.131
_refine_ls_R_factor_all          0.0220
_refine_ls_R_factor_gt           0.0214
_refine_ls_shift/su_max          0.001
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0342P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0485
_refine_ls_wR_factor_ref         0.0485
_reflns_number_gt                724
_reflns_number_total             799
_reflns_threshold_expression     I>2sigma(I)
_cod_data_source_file            wm2631.cif
_cod_data_source_block           I
_cod_original_sg_symbol_H-M      'R -3 m'
_cod_database_code               2235288
_cod_database_fobs_code          2235288