Centrosymmetric or Noncentrosymmetric? Case Study and Structural Redetermination of Sr~5~Nb~5~O~17~
Abrahams, Sidney C.; Schmalle, Helmut W.; Williams, Tim; Reller, Armin; Lichtenberg, Frank; Widmer, Daniel; Bednorz, J. Georg; Spreiter, Rolf; Bosshard, Christian; Günter, Peter; Acta Crystallographica, Section B 54 (1998) 399–416; doi:

data_2002950
_publ_section_title
;
 Centrosymmetric or Noncentrosymmetric?
 Case Study and Structural Redetermination of Sr~5~Nb~5~O~17~
;
_journal_name_full               'Acta Crystallographica, Section B'
_journal_page_first              399
_journal_page_last               416
_journal_volume                  54
_journal_year                    1998
_chemical_formula_sum            'Nb5 O17 Sr5'
_chemical_formula_weight         1174.65
_chemical_name_systematic
;
 strontium niobium oxide
;
_space_group_IT_number           58
_space_group_name_Hall           '-P 2 2n'
_space_group_name_H-M_alt        'P n n m'
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  '-P 2 2n'
_symmetry_space_group_name_H-M   'P n n m'
_cell_angle_alpha                90.00
_cell_angle_beta                 90.00
_cell_angle_gamma                90.00
_cell_formula_units_Z            2
_cell_length_a                   32.456(5)
_cell_length_b                   5.674(2)
_cell_length_c                   3.995(2)
_cell_measurement_reflns_used    25
_cell_measurement_temperature    295(2)
_cell_measurement_theta_max      12.0
_cell_measurement_theta_min      5.6
_cell_volume                     735.7(5)
_diffrn_ambient_temperature      295(2)
_diffrn_measurement_device       'Enraf-Nonius CAD-4 diffractometer'
_diffrn_measurement_method       '\w-2\q scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     .71073
_diffrn_reflns_av_R_equivalents  .0680
_diffrn_reflns_av_sigmaI/netI    .0600
_diffrn_reflns_limit_h_max       58
_diffrn_reflns_limit_h_min       0
_diffrn_reflns_limit_k_max       10
_diffrn_reflns_limit_k_min       -10
_diffrn_reflns_limit_l_max       7
_diffrn_reflns_limit_l_min       -7
_diffrn_reflns_number            8738
_diffrn_reflns_theta_max         39.91
_diffrn_reflns_theta_min         1.25
_diffrn_standards_decay_%        .1
_diffrn_standards_interval_count 400
_diffrn_standards_interval_time  180
_diffrn_standards_number         3
_exptl_absorpt_coefficient_mu    21.803
_exptl_absorpt_correction_T_max  .4829
_exptl_absorpt_correction_T_min  .0648
_exptl_absorpt_correction_type   numerical
_exptl_crystal_colour            Black
_exptl_crystal_density_diffrn    5.303
_exptl_crystal_description       Platelike
_exptl_crystal_F_000             1062
_exptl_crystal_size_max          .387
_exptl_crystal_size_mid          .135
_exptl_crystal_size_min          .035
_refine_diff_density_max         3.921
_refine_diff_density_min         -3.319
_refine_ls_extinction_coef       .00421(17)
_refine_ls_extinction_method     SHELXL
_refine_ls_goodness_of_fit_all   .716
_refine_ls_goodness_of_fit_obs   .809
_refine_ls_hydrogen_treatment    ?
_refine_ls_matrix_type           full
_refine_ls_number_parameters     86
_refine_ls_number_reflns         2509
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      .716
_refine_ls_restrained_S_obs      .809
_refine_ls_R_factor_all          .0987
_refine_ls_R_factor_obs          .0221
_refine_ls_shift/esd_max         .001
_refine_ls_shift/esd_mean        .000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0296P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_all         .0779
_refine_ls_wR_factor_obs         .0551
_reflns_number_observed          1172
_reflns_number_total             2509
_reflns_observed_criterion       >2sigma(I)
_cod_depositor_comments
;
The following automatic conversions were performed:
'_symmetry_cell_setting' value 'Orthorhombic' changed to 'orthorhombic'
according to '/home/saulius/struct/CIF-dictionaries/cif_core.dic'
dictionary named 'cif_core.dic' version 2.4.1 from 2010-06-29.

Automatic conversion script
Id: cif_fix_enum 1527 2010-12-29 10:47:43Z saulius 

The following automatic conversions were performed:

'_refine_ls_weighting_scheme' value 'calc
w=1/[\s^2^(Fo^2^)+(0.0296P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3' was
changed to 'calc'. New tag '_refine_ls_weighting_details' was
created. The value of the new tag was set to
'w=1/[\s^2^(Fo^2^)+(0.0296P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'.

Automatic conversion script
Id: cif_fix_values 3143 2015-03-26 13:38:13Z robertas 
;
_cod_database_code               2002950