Dicerium disilicate, Ce~2~[Si~2~O~7~]
Bin Deng; James A. Ibers; Acta Crystallographica Section E 61 (2005) i76–i78; doi:10.1107/S1600536805011049

data_2205827
_publ_section_title
;
 Dicerium disilicate, Ce~2~[Si~2~O~7~]
;
_journal_issue                   5
_journal_name_full               'Acta Crystallographica Section E'
_journal_page_first              i76
_journal_page_last               i78
_journal_paper_doi               10.1107/S1600536805011049
_journal_volume                  61
_journal_year                    2005
_chemical_formula_iupac          'Ce4 [Si2 O7]2'
_chemical_formula_moiety         'Ce4 (Si2 O7)2'
_chemical_formula_structural     'Ce4 (Si2 O7)2'
_chemical_formula_sum            'Ce4 O14 Si4'
_chemical_formula_weight         896.84
_chemical_name_common            'Cerium disilicate'
_chemical_name_systematic
;
Dicerium disilicate
;
_space_group_IT_number           76
_symmetry_cell_setting           tetragonal
_symmetry_space_group_name_Hall  'P 4w'
_symmetry_space_group_name_H-M   'P 41'
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL97
_cell_angle_alpha                90.00
_cell_angle_beta                 90.00
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   6.7964(3)
_cell_length_b                   6.7964(3)
_cell_length_c                   24.7282(14)
_cell_measurement_reflns_used    2729
_cell_measurement_temperature    153(2)
_cell_measurement_theta_max      28.93
_cell_measurement_theta_min      3.0
_cell_volume                     1142.22(10)
_computing_cell_refinement       'SAINT (Bruker, 2003)'
_computing_data_collection       'SMART (Bruker,2003)'
_computing_data_reduction        SAINT
_computing_molecular_graphics    'XP in SHELXTL'
_computing_publication_material  SHELXTL
_computing_structure_refinement  'SHELXTL (Sheldrick, 2003)'
_computing_structure_solution    'SHELXTL (Sheldrick, 2003)'
_diffrn_ambient_temperature      153(2)
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 0.934
_diffrn_measurement_device_type  'Bruker SMART 1000 CCD area-detector'
_diffrn_measurement_method       \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  0.0343
_diffrn_reflns_av_sigmaI/netI    0.0307
_diffrn_reflns_limit_h_max       9
_diffrn_reflns_limit_h_min       -9
_diffrn_reflns_limit_k_max       9
_diffrn_reflns_limit_k_min       -8
_diffrn_reflns_limit_l_max       31
_diffrn_reflns_limit_l_min       -31
_diffrn_reflns_number            10648
_diffrn_reflns_theta_full        25.00
_diffrn_reflns_theta_max         28.93
_diffrn_reflns_theta_min         3.00
_diffrn_standards_decay_%        <1
_diffrn_standards_interval_count 0
_diffrn_standards_interval_time  0
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    16.142
_exptl_absorpt_correction_T_max  0.741
_exptl_absorpt_correction_T_min  0.482
_exptl_absorpt_correction_type   numerical
_exptl_absorpt_process_details
'face-indexed using SHELXTL (Sheldrick, 2003)'
_exptl_crystal_colour            green
_exptl_crystal_density_diffrn    5.215
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             1600
_exptl_crystal_size_max          0.102
_exptl_crystal_size_mid          0.044
_exptl_crystal_size_min          0.040
_refine_diff_density_max         2.400
_refine_diff_density_min         -1.193
_refine_ls_abs_structure_details 'Flack (1983), with 1284 Friedel pairs'
_refine_ls_abs_structure_Flack   0.522(19)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.153
_refine_ls_hydrogen_treatment    none
_refine_ls_matrix_type           full
_refine_ls_number_parameters     200
_refine_ls_number_reflns         2729
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.153
_refine_ls_R_factor_all          0.0258
_refine_ls_R_factor_gt           0.0243
_refine_ls_shift/su_max          0.001
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w = 1/[\s^2^(Fo^2^)+(0.028P)^2^] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0548
_refine_ls_wR_factor_ref         0.0554
_reflns_number_gt                2637
_reflns_number_total             2729
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            wm6067.cif
_cod_data_source_block           I
_cod_database_code               2205827
_cod_database_fobs_code          2205827