The commensurate composite σ-structure of β-tantalum
Arakcheeva, Alla; Chapuis, Gervais; Birkedal, Henrik; Pattison, Phil; Grinevitch, Vladimir; Acta Crystallographica Section B 59 (2003) 324–336; doi:10.1107/S0108768103009005

data_2103918
_publ_section_title
;
 The commensurate composite \s-structure of \b-tantalum
;
_journal_issue                   3
_journal_name_full               'Acta Crystallographica Section B'
_journal_page_first              324
_journal_page_last               336
_journal_paper_doi               10.1107/S0108768103009005
_journal_volume                  59
_journal_year                    2003
_chemical_formula_moiety         30.0Ta
_chemical_formula_sum            Ta
_chemical_formula_weight         5428.4
_chemical_name_systematic        ' Metal'
_space_group_IT_number           81
_symmetry_cell_setting           tetragonal
_symmetry_space_group_name_Hall  'P -4'
_symmetry_space_group_name_H-M   'P -4'
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            30
_cell_length_a                   10.1815(5)
_cell_length_b                   10.1815(5)
_cell_length_c                   5.29500(10)
_cell_measurement_reflns_used    8379
_cell_measurement_temperature    120(2)
_cell_measurement_theta_max      30.52
_cell_measurement_theta_min      3.79
_cell_volume                     548.90(4)
_computing_publication_material  '(Jana2000; Petricek and Dusek, 2000)'
_computing_structure_refinement  '(Jana2000; Petricek and Dusek, 2000)'
_diffrn_ambient_temperature      120(2)
_diffrn_detector_area_resol_mean 6.667
_diffrn_measurement_device_type  MAR345
_diffrn_measurement_method       \f-scans
_diffrn_radiation_monochromator
; Si(111) double crystal monochromator with bent second crystal for
sagital focusing
;
_diffrn_radiation_source         'bending magnet 1 at ESRF'
_diffrn_radiation_type           synchrotron
_diffrn_radiation_wavelength     0.70013
_diffrn_reflns_av_R_equivalents  0.0816
_diffrn_reflns_av_sigmaI/netI    0.0612
_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       7
_diffrn_reflns_limit_l_min       -7
_diffrn_reflns_number            8379
_diffrn_reflns_theta_max         30.52
_diffrn_reflns_theta_min         3.79
_exptl_absorpt_coefficient_mu    148.66
_exptl_absorpt_correction_T_max  0.0493
_exptl_absorpt_correction_T_min  0.0241
_exptl_absorpt_correction_type   sphere
_exptl_crystal_colour            silver
_exptl_crystal_density_diffrn    16.4170(12)
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       'isometric irregular'
_exptl_crystal_F_000             2190
_exptl_crystal_size_max          0.022
_exptl_crystal_size_mid          0.02
_exptl_crystal_size_min          0.018
_exptl_crystal_size_rad          0.02
_refine_diff_density_max         11.04
_refine_diff_density_min         -9.89
_refine_ls_extinction_coef       0.0009(3)
_refine_ls_extinction_method
'B-C type 1 Gaussian isotropic (Becker & Coppens, 1974)'
_refine_ls_goodness_of_fit_ref   1.74
_refine_ls_number_parameters     72
_refine_ls_number_reflns         1530
_refine_ls_R_factor_all          0.0363
_refine_ls_R_factor_gt           0.0363
_refine_ls_shift/su_max          0.0007
_refine_ls_shift/su_mean         0.0002
_refine_ls_structure_factor_coef F
_refine_ls_weighting_details     w=1/(\s^2^(F)+0.0001F^2^)
_refine_ls_weighting_scheme      sigma
_refine_ls_wR_factor_gt          0.0501
_refine_ls_wR_factor_ref         0.0501
_reflns_number_gt                1530
_reflns_number_total             1708
_reflns_threshold_expression     I>3\s(I)
_cod_data_source_file            sn0032.cif
_cod_data_source_block           II
_cod_original_sg_symbol_H-M      P-4
_cod_original_formula_sum        Ta30.0
_cod_database_code               2103918