Helical chain observed under transmission electron microscope: Synthesis and structure refinement of lutetium disilicate Lu2Si2O7
Wang, Chao; Liu, Xiaoyang; Fleet, M. E.; Li, Jixue; Feng, Shouhua; Xu, Ruren; Jin, Zhenmin; CrystEngComm 12 (2010) 1617–; doi:10.1039/b919658g

data_7212104
_publ_section_title
;
 Helical chain observed under transmission electron microscope: Synthesis
 and structure refinement of lutetium disilicate Lu2Si2O7
;
_journal_issue                   5
_journal_name_full               CrystEngComm
_journal_page_first              1617
_journal_paper_doi               10.1039/b919658g
_journal_volume                  12
_journal_year                    2010
_chemical_formula_moiety         'Lu2 O7 Si2'
_chemical_formula_sum            'Lu2 O7 Si2'
_chemical_formula_weight         518.12
_chemical_melting_point          ?
_chemical_name_systematic
;
?
;
_space_group_IT_number           96
_symmetry_cell_setting           tetragonal
_symmetry_space_group_name_Hall  'P 4nw 2abw'
_symmetry_space_group_name_H-M   'P 43 21 2'
_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                90.00
_cell_formula_units_Z            4
_cell_length_a                   6.5621(9)
_cell_length_b                   6.5621(9)
_cell_length_c                   11.954(2)
_cell_measurement_reflns_used    759
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      30.01
_cell_measurement_theta_min      3.54
_cell_volume                     514.75(13)
_computing_cell_refinement       'Bruker SMART'
_computing_data_collection       'Bruker SMART'
_computing_data_reduction        'Bruker SAINT'
_computing_molecular_graphics    SHELXP-97
_computing_publication_material  SHELXTL
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      293(2)
_diffrn_detector_area_resol_mean 9.00cm
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 1.000
_diffrn_measurement_device_type  'CCD area detector'
_diffrn_measurement_method       'phi and omega scans'
_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  0.1128
_diffrn_reflns_av_sigmaI/netI    0.0579
_diffrn_reflns_limit_h_max       9
_diffrn_reflns_limit_h_min       -8
_diffrn_reflns_limit_k_max       9
_diffrn_reflns_limit_k_min       -9
_diffrn_reflns_limit_l_max       16
_diffrn_reflns_limit_l_min       -16
_diffrn_reflns_number            8760
_diffrn_reflns_theta_full        30.01
_diffrn_reflns_theta_max         30.01
_diffrn_reflns_theta_min         3.54
_diffrn_standards_decay_%        none
_diffrn_standards_interval_count none
_diffrn_standards_interval_time  none
_diffrn_standards_number         none
_exptl_absorpt_coefficient_mu    38.581
_exptl_absorpt_correction_T_max  0.483
_exptl_absorpt_correction_T_min  0.412
_exptl_absorpt_correction_type   empirical
_exptl_absorpt_process_details   SADABS
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    6.686
_exptl_crystal_density_meas      ?
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             904
_exptl_crystal_size_max          0.03
_exptl_crystal_size_mid          0.02
_exptl_crystal_size_min          0.02
_refine_diff_density_max         3.388
_refine_diff_density_min         -2.452
_refine_diff_density_rms         0.593
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   0.01(5)
_refine_ls_extinction_coef       0.0118(7)
_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   1.064
_refine_ls_matrix_type           full
_refine_ls_number_parameters     52
_refine_ls_number_reflns         759
_refine_ls_number_restraints     6
_refine_ls_restrained_S_all      1.061
_refine_ls_R_factor_all          0.0517
_refine_ls_R_factor_gt           0.0379
_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^)+(0.0427P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0750
_refine_ls_wR_factor_ref         0.0815
_reflns_number_gt                651
_reflns_number_total             759
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            b919658g.txt
_cod_data_source_block           sad
_cod_depositor_comments
;
The following automatic conversions were performed:

'_chemical_melting_point' value 'not measured' was changed to '?' -
the value is undefined or not given.

'_symmetry_cell_setting' value
'Tetragonal' changed to 'tetragonal' according to
/home/saulius/struct/CIF-dictionaries/cif_core.dic dictionary named
'cif_core.dic' version 2.4.2 from 2011-04-26.

Automatic conversion script
Id: cif_fix_values 1891 2012-01-12 08:04:46Z andrius 

The following automatic conversions were performed:

'_exptl_crystal_density_meas' value 'none' was changed to '?' - the
value is perceived as not measured.

Automatic conversion script
Id: cif_fix_values 3008 2015-01-20 13:52:24Z robertas 
;
_cod_original_cell_volume        514.74(14)
_cod_original_sg_symbol_H-M      P4(3)2(1)2
_cod_database_code               7212104