Crystal chemistry and the role of ionic radius in rare earth tetrasilicates: Ba<sub>2</sub>RE<sub>2</sub>Si<sub>4</sub>O<sub>12</sub>F<sub>2</sub> (RE = Er<sup>3+</sup>-Lu<sup>3+</sup>) and Ba<sub>2</sub>RE<sub>2</sub>Si<sub>4</sub>O<sub>13</sub> (RE = La<sup>3+</sup>-Ho<sup>3+</sup>).
Fulle, Kyle; Sanjeewa, Liurukara D.; McMillen, Colin D.; Kolis, Joseph W.; Acta crystallographica Section B, Structural science, crystal engineering and materials 73 (2017) 907–915; doi:10.1107/S2052520617009544

data_2311787
_publ_section_title
;
 Crystal chemistry and the role of ionic radius in rare earth
 tetrasilicates:
 Ba<sub>2</sub>RE<sub>2</sub>Si<sub>4</sub>O<sub>12</sub>F<sub>2</sub> (RE
 = Er<sup>3+</sup>-Lu<sup>3+</sup>) and
 Ba<sub>2</sub>RE<sub>2</sub>Si<sub>4</sub>O<sub>13</sub> (RE =
 La<sup>3+</sup>-Ho<sup>3+</sup>).
;
_journal_issue                   'Pt 5'
_journal_name_full
'Acta crystallographica Section B, Structural science, crystal engineering and materials'
_journal_page_first              907
_journal_page_last               915
_journal_paper_doi               10.1107/S2052520617009544
_journal_volume                  73
_journal_year                    2017
_chemical_formula_sum            'Ba2 F2 Lu2 O12 Si4'
_chemical_formula_weight         966.98
_space_group_crystal_system      triclinic
_space_group_IT_number           2
_space_group_name_Hall           '-P 1'
_space_group_name_H-M_alt        'P -1'
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-2014/7
_cell_angle_alpha                107.73(3)
_cell_angle_beta                 101.81(4)
_cell_angle_gamma                93.01(4)
_cell_formula_units_Z            1
_cell_length_a                   5.451(3)
_cell_length_b                   7.1227(18)
_cell_length_c                   8.8937(18)
_cell_measurement_reflns_used    1958
_cell_measurement_temperature    298(2)
_cell_measurement_theta_max      25.9920
_cell_measurement_theta_min      2.4718
_cell_volume                     319.5(2)
_computing_cell_refinement       'CrystalClear (Rigaku/MSC, 2008)'
_computing_data_collection       'CrystalClear (Rigaku/MSC, 2008)'
_computing_data_reduction        'CrystalClear (Rigaku/MSC, 2008)'
_computing_molecular_graphics    'DIAMOND (Bradenburg, 1999)'
_computing_publication_material  'SHELXL-2014/7 (Sheldrick, 2014)'
_computing_structure_refinement  'SHELXL-2014/7 (Sheldrick, 2014)'
_computing_structure_solution    'SHELXL-2014/7 (Sheldrick, 2014)'
_diffrn_ambient_temperature      298(2)
_diffrn_detector_area_resol_mean 14.6199
_diffrn_measured_fraction_theta_full 0.985
_diffrn_measured_fraction_theta_max 0.985
_diffrn_measurement_device_type  'Rigaku AFC8S'
_diffrn_measurement_method       '\w scans'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0397
_diffrn_reflns_av_unetI/netI     0.0417
_diffrn_reflns_Laue_measured_fraction_full 0.985
_diffrn_reflns_Laue_measured_fraction_max 0.985
_diffrn_reflns_limit_h_max       5
_diffrn_reflns_limit_h_min       -6
_diffrn_reflns_limit_k_max       8
_diffrn_reflns_limit_k_min       -8
_diffrn_reflns_limit_l_max       10
_diffrn_reflns_limit_l_min       -10
_diffrn_reflns_number            2710
_diffrn_reflns_point_group_measured_fraction_full 0.985
_diffrn_reflns_point_group_measured_fraction_max 0.985
_diffrn_reflns_theta_full        25.241
_diffrn_reflns_theta_max         25.241
_diffrn_reflns_theta_min         3.026
_diffrn_source                   'fine-focus sealed tube'
_exptl_absorpt_coefficient_mu    21.860
_exptl_absorpt_correction_T_max  1.0000
_exptl_absorpt_correction_T_min  0.2726
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'REQAB, CrystalClear'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    5.026
_exptl_crystal_description       block
_exptl_crystal_F_000             424
_exptl_crystal_size_max          0.145
_exptl_crystal_size_mid          0.136
_exptl_crystal_size_min          0.127
_refine_diff_density_max         2.604
_refine_diff_density_min         -3.567
_refine_diff_density_rms         0.456
_refine_ls_extinction_coef       0.0255(18)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     'SHELXL-2014/7 (Sheldrick 2014'
_refine_ls_goodness_of_fit_ref   1.066
_refine_ls_hydrogen_treatment    undef
_refine_ls_matrix_type           full
_refine_ls_number_parameters     101
_refine_ls_number_reflns         1148
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.066
_refine_ls_R_factor_all          0.0368
_refine_ls_R_factor_gt           0.0359
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0790P)^2^+31.2028P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0983
_refine_ls_wR_factor_ref         0.0990
_reflns_Friedel_coverage         0.000
_reflns_number_gt                1116
_reflns_number_total             1148
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            rm5005sup1.cif
_cod_data_source_block           Lu
_cod_database_code               2311787
_shelx_shelxl_version_number     2014/7
_shelx_estimated_absorpt_t_min   0.144
_shelx_estimated_absorpt_t_max   0.168
_shelx_res_checksum              52407
_shelx_hkl_checksum              38855