Single-crystal X-ray refinement of wilkinsonite, Na~2~Fe~4~^2+^Fe~2~^3+^Si~6~O~20~
Burt, Jason B.; Downs, Robert T.; Costin, Gelu; Acta Crystallographica Section E 63 (2007) i122–i124; doi:10.1107/S1600536807015048

data_2213151
_publ_section_title
;
 Single-crystal X-ray refinement of wilkinsonite,
 Na~2~Fe~4~^2+^Fe~2~^3+^Si~6~O~20~
;
_journal_coeditor_code           BR2035
_journal_issue                   5
_journal_name_full               'Acta Crystallographica Section E'
_journal_page_first              i122
_journal_page_last               i124
_journal_paper_doi               10.1107/S1600536807015048
_journal_volume                  63
_journal_year                    2007
_chemical_formula_structural     'Na2 Fe6 Si6 O20'
_chemical_formula_sum            'Fe6 Na2 O20 Si6'
_chemical_formula_weight         869.62
_chemical_name_common            wilkinsonite
_chemical_name_systematic
;
disodium hexairon(II,III) hexasilicon icosaoxide
;
_space_group_IT_number           2
_symmetry_cell_setting           triclinic
_symmetry_space_group_name_Hall  '-P 1'
_symmetry_space_group_name_H-M   'P -1'
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL97
_cell_angle_alpha                105.048(3)
_cell_angle_beta                 96.461(3)
_cell_angle_gamma                125.302(2)
_cell_formula_units_Z            2
_cell_length_a                   10.3355(5)
_cell_length_b                   10.7847(4)
_cell_length_c                   8.9142(4)
_cell_measurement_reflns_used    1568
_cell_measurement_temperature    296(2)
_cell_measurement_theta_max      29.27
_cell_measurement_theta_min      2.51
_cell_volume                     738.37(7)
_computing_cell_refinement       SMART
_computing_data_collection       'SMART (Bruker, 2003)'
_computing_data_reduction        'SAINT (Bruker, 2005)'
_computing_molecular_graphics    'XTALDRAW (Downs & Hall-Wallace, 2003)'
_computing_publication_material  'SHELXTL (Bruker, 1997)'
_computing_structure_refinement  'SHELXL97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS97 (Sheldrick, 1997)'
_diffrn_ambient_temperature      296(2)
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 0.999
_diffrn_measurement_device_type  'Bruker SMART CCD area-detector'
_diffrn_measurement_method       '\f and \w'
_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  0.0626
_diffrn_reflns_av_sigmaI/netI    0.0770
_diffrn_reflns_limit_h_max       14
_diffrn_reflns_limit_h_min       -14
_diffrn_reflns_limit_k_max       14
_diffrn_reflns_limit_k_min       -15
_diffrn_reflns_limit_l_max       12
_diffrn_reflns_limit_l_min       -12
_diffrn_reflns_number            16331
_diffrn_reflns_theta_full        30.03
_diffrn_reflns_theta_max         30.03
_diffrn_reflns_theta_min         2.18
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    6.415
_exptl_absorpt_correction_T_max  0.774
_exptl_absorpt_correction_T_min  0.733
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   '(SADABS; Sheldrick, 2005)'
_exptl_crystal_colour            black
_exptl_crystal_density_diffrn    3.911
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       prismatic
_exptl_crystal_F_000             844
_exptl_crystal_size_max          0.05
_exptl_crystal_size_mid          0.045
_exptl_crystal_size_min          0.04
_refine_diff_density_max         1.092
_refine_diff_density_min         -0.893
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.003
_refine_ls_matrix_type           full
_refine_ls_number_parameters     310
_refine_ls_number_reflns         4312
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.003
_refine_ls_R_factor_all          0.0857
_refine_ls_R_factor_gt           0.0413
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w = 1/[\s^2^(Fo^2^)+(0.0325P)^2^] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0763
_refine_ls_wR_factor_ref         0.0886
_reflns_number_gt                2812
_reflns_number_total             4312
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            br2035.cif
_cod_data_source_block           I
_cod_database_code               2213151
_cod_database_fobs_code          2213151