High-pressure syntheses of α-RE~2~B~4~O~9~ (RE = Sm, Ho), with a structure type displaying edge-sharing BO~4~ tetrahedra
Emme, Holger; Huppertz, Hubert; Acta Crystallographica Section C 61 (2005) i29–i31; doi:10.1107/S0108270104030446

data_2014707
_publ_section_title
;
 High-pressure syntheses of \a-RE~2~B~4~O~9~ (RE = Sm, Ho), with a
 structure type displaying edge-sharing BO~4~ tetrahedra
;
_journal_issue                   3
_journal_name_full               'Acta Crystallographica Section C'
_journal_page_first              i29
_journal_page_last               i31
_journal_paper_doi               10.1107/S0108270104030446
_journal_volume                  61
_journal_year                    2005
_chemical_formula_iupac          'Sm2 B4 O9'
_chemical_formula_moiety         'Sm2 B4 O9'
_chemical_formula_sum            'B4 O9 Sm2'
_chemical_formula_weight         487.94
_chemical_name_common            '\a-Disamarium tetraborate'
_chemical_name_systematic
;
Disamarium tetraborate
;
_space_group_IT_number           15
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-C 2yc'
_symmetry_space_group_name_H-M   'C 1 2/c 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_cell_angle_alpha                90.00
_cell_angle_beta                 99.85(3)
_cell_angle_gamma                90.00
_cell_formula_units_Z            20
_cell_length_a                   25.572(5)
_cell_length_b                   4.4516(9)
_cell_length_c                   24.967(5)
_cell_measurement_reflns_used    8000
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      32.1
_cell_measurement_theta_min      3.4
_cell_volume                     2800.3(10)
_computing_cell_refinement       'Please provide missing details'
_computing_data_collection       'Please provide missing details'
_computing_data_reduction        'Please provide missing details'
_computing_molecular_graphics    'DIAMOND (Brandenburg & Berndt, 1999)'
_computing_publication_material  'enCIFer (Allen et al., 2004) and SHELXL97'
_computing_structure_refinement  'SHELXL97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS97 (Sheldrick, 1997)'
_diffrn_ambient_temperature      293(2)
_diffrn_measured_fraction_theta_full 0.930
_diffrn_measured_fraction_theta_max 0.930
_diffrn_measurement_device_type  'STOE IPDS'
_diffrn_measurement_method       'profile data from \f 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  0.0238
_diffrn_reflns_av_sigmaI/netI    0.0197
_diffrn_reflns_limit_h_max       32
_diffrn_reflns_limit_h_min       -32
_diffrn_reflns_limit_k_max       4
_diffrn_reflns_limit_k_min       -5
_diffrn_reflns_limit_l_max       31
_diffrn_reflns_limit_l_min       -31
_diffrn_reflns_number            9846
_diffrn_reflns_theta_full        26.50
_diffrn_reflns_theta_max         26.50
_diffrn_reflns_theta_min         3.37
_diffrn_standards_decay_%        0
_diffrn_standards_interval_count 0
_diffrn_standards_interval_time  0
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    20.797
_exptl_absorpt_correction_T_max  0.43509
_exptl_absorpt_correction_T_min  0.38079
_exptl_absorpt_correction_type   '\y scan'
_exptl_absorpt_process_details   '(XPREP; Siemens, 1990-1996)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    5.787
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       rod
_exptl_crystal_F_000             4320
_exptl_crystal_size_max          0.05
_exptl_crystal_size_mid          0.05
_exptl_crystal_size_min          0.04
_refine_diff_density_max         0.799
_refine_diff_density_min         -0.660
_refine_ls_extinction_coef       0.000226(7)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     SHELXL97
_refine_ls_goodness_of_fit_ref   0.952
_refine_ls_hydrogen_treatment    none
_refine_ls_matrix_type           full
_refine_ls_number_parameters     340
_refine_ls_number_reflns         2709
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      0.952
_refine_ls_R_factor_all          0.0186
_refine_ls_R_factor_gt           0.0135
_refine_ls_shift/su_max          0.002
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0169P)^2^] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0279
_refine_ls_wR_factor_ref         0.0287
_reflns_number_gt                2381
_reflns_number_total             2709
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            iz1049.cif
_cod_data_source_block           I
_cod_original_sg_symbol_H-M      'C 2/c'
_cod_original_formula_sum        'Sm2 B4 O9'
_cod_database_code               2014707
_cod_database_fobs_code          2014707