Single-crystal neutron diffraction investigation on crystals belonging to the langasite family: a comparative study
Chitra, R.; Choudhury, R. R.; Acta Crystallographica Section B 66 (2010) 497–502; doi:10.1107/S0108768110031459

data_2017773
_publ_section_title
;
 Single-crystal neutron diffraction investigation on crystals belonging to
 the langasite family: a comparative study
;
_journal_issue                   5
_journal_name_full               'Acta Crystallographica Section B'
_journal_page_first              497
_journal_page_last               502
_journal_paper_doi               10.1107/S0108768110031459
_journal_volume                  66
_journal_year                    2010
_chemical_formula_moiety         'Ga5.34 La3 O14 Si0.36 Ta0.29'
_chemical_formula_sum            'Ga5.34 La3 O14 Si0.36 Ta0.29'
_chemical_formula_weight         1075.12
_chemical_name_common            Langatate
_chemical_name_systematic
;
 langtate
;
_space_group_IT_number           150
_symmetry_cell_setting           trigonal
_symmetry_space_group_name_Hall  'P 3 2"'
_symmetry_space_group_name_H-M   'P 3 2 1'
_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            1
_cell_length_a                   8.195(7)
_cell_length_b                   8.195(7)
_cell_length_c                   5.1180(10)
_cell_measurement_reflns_used    50
_cell_measurement_temperature    300(2)
_cell_measurement_theta_max      44
_cell_measurement_theta_min      4.0
_cell_volume                     297.7(4)
_computing_cell_refinement       REFINE
_computing_data_collection       SCAD
_computing_data_reduction        DATRED
_computing_molecular_graphics    ORTEP
_computing_publication_material  SHELX
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_diffrn_ambient_temperature      300(2)
_diffrn_measured_fraction_theta_full 0.991
_diffrn_measured_fraction_theta_max 0.991
_diffrn_measurement_device_type  'Four circle diffractometer'
_diffrn_measurement_method       \t-\2t
_diffrn_radiation_monochromator  Cu
_diffrn_radiation_probe          neutron
_diffrn_radiation_source         'dhruva reactor'
_diffrn_radiation_type           neutron
_diffrn_radiation_wavelength     0.99500
_diffrn_reflns_av_R_equivalents  0.0216
_diffrn_reflns_av_sigmaI/netI    0.0263
_diffrn_reflns_limit_h_max       11
_diffrn_reflns_limit_h_min       -11
_diffrn_reflns_limit_k_max       10
_diffrn_reflns_limit_k_min       -5
_diffrn_reflns_limit_l_max       7
_diffrn_reflns_limit_l_min       -6
_diffrn_reflns_number            461
_diffrn_reflns_theta_full        44.14
_diffrn_reflns_theta_max         44.14
_diffrn_reflns_theta_min         4.02
_diffrn_standards_decay_%        <3%
_diffrn_standards_interval_count 25
_diffrn_standards_number         2
_exptl_absorpt_coefficient_mu    0.016
_exptl_absorpt_correction_type   integration
_exptl_absorpt_process_details   Datred
_exptl_crystal_colour            Colourless
_exptl_crystal_density_diffrn    6.000
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       cubic
_exptl_crystal_F_000             148
_exptl_crystal_size_max          3
_exptl_crystal_size_mid          3
_exptl_crystal_size_min          3
_refine_diff_density_max         0.833
_refine_diff_density_min         -0.833
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   10(10)
_refine_ls_extinction_coef       2.10(17)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     SHELXL
_refine_ls_goodness_of_fit_ref   1.136
_refine_ls_matrix_type           full
_refine_ls_number_parameters     42
_refine_ls_number_reflns         454
_refine_ls_number_restraints     2
_refine_ls_restrained_S_all      1.134
_refine_ls_R_factor_all          0.0472
_refine_ls_R_factor_gt           0.0451
_refine_ls_shift/su_max          0.012
_refine_ls_shift/su_mean         0.001
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0939P)^2^+1.5721P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1304
_refine_ls_wR_factor_ref         0.1339
_reflns_number_gt                440
_reflns_number_total             454
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            bp5031.cif
_cod_data_source_block           LGST
_cod_original_sg_symbol_H-M      'P 321'
_cod_database_code               2017773
_cod_database_fobs_code          2017773