Synthesis, structure, and polymorphism of A3LnSi2O7 (A=Na, K; Ln=Sm, Ho, Yb)
Latshaw, Allison M.; Yeon, Jeongho; Smith, Mark D.; zur Loye, Hans-Conrad; Journal of Solid State Chemistry 235 (2016) 100–106; doi:10.1016/j.jssc.2015.12.013

data_1561594
_publ_section_title
;
 Synthesis, structure, and polymorphism of A3LnSi2O7 (A=Na, K; Ln=Sm, Ho,
 Yb)
;
_journal_name_full               'Journal of Solid State Chemistry'
_journal_page_first              100
_journal_page_last               106
_journal_paper_doi               10.1016/j.jssc.2015.12.013
_journal_volume                  235
_journal_year                    2016
_chemical_formula_moiety         'K3 O7 Si2 Sm'
_chemical_formula_sum            'K3 O7 Si2 Sm'
_chemical_formula_weight         435.83
_space_group_crystal_system      hexagonal
_space_group_IT_number           193
_space_group_name_Hall           '-P 6c 2'
_space_group_name_H-M_alt        'P 63/m c m'
_atom_sites_solution_hydrogens   .
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                120
_cell_formula_units_Z            6
_cell_length_a                   9.97640(10)
_cell_length_b                   9.97640(10)
_cell_length_c                   14.4844(3)
_cell_measurement_reflns_used    7870
_cell_measurement_temperature    296(2)
_cell_measurement_theta_max      35.080
_cell_measurement_theta_min      2.812
_cell_volume                     1248.47(3)
_computing_cell_refinement       'SAINT-Plus Version 6.45 (Bruker, 2001)'
_computing_data_collection       'SMART Version 5.631 (Bruker, 2001)'
_computing_data_reduction        'SAINT-Plus Version 6.45 (Bruker, 2001)'
_computing_molecular_graphics    various
_computing_publication_material  various
_computing_structure_refinement  'SHELXL-2013 (Sheldrick, 2013)'
_computing_structure_solution    'SHELXS97 (Sheldrick, 1997)'
_diffrn_ambient_temperature      296(2)
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 1.000
_diffrn_measurement_device_type  'Bruker SMART APEX CCD diffractometer'
_diffrn_measurement_method       'omega and phi scans'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0363
_diffrn_reflns_av_unetI/netI     0.0125
_diffrn_reflns_Laue_measured_fraction_full 1.000
_diffrn_reflns_Laue_measured_fraction_max 1.000
_diffrn_reflns_limit_h_max       15
_diffrn_reflns_limit_h_min       -15
_diffrn_reflns_limit_k_max       14
_diffrn_reflns_limit_k_min       -14
_diffrn_reflns_limit_l_max       23
_diffrn_reflns_limit_l_min       -23
_diffrn_reflns_number            28791
_diffrn_reflns_point_group_measured_fraction_full 1.000
_diffrn_reflns_point_group_measured_fraction_max 1.000
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         35.267
_diffrn_reflns_theta_min         2.357
_diffrn_source                   'sealed tube'
_exptl_absorpt_coefficient_mu    8.842
_exptl_absorpt_correction_T_max  1.0000
_exptl_absorpt_correction_T_min  0.6204
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'SADABS Version 2.05 (Bruker, 2001)'
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    3.478
_exptl_crystal_description       prism
_exptl_crystal_F_000             1218
_exptl_crystal_size_max          0.140
_exptl_crystal_size_mid          0.100
_exptl_crystal_size_min          0.080
_refine_diff_density_max         1.035
_refine_diff_density_min         -0.784
_refine_diff_density_rms         0.166
_refine_ls_extinction_coef       0.00074(14)
_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   1.184
_refine_ls_hydrogen_treatment    undef
_refine_ls_matrix_type           full
_refine_ls_number_parameters     41
_refine_ls_number_reflns         1047
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.184
_refine_ls_R_factor_all          0.0354
_refine_ls_R_factor_gt           0.0279
_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^)+(0.0354P)^2^+2.4953P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0733
_refine_ls_wR_factor_ref         0.0766
_reflns_number_gt                881
_reflns_number_total             1047
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            mmc1.cif
_cod_data_source_block           K3SmSi2O7
_cod_original_cell_volume        1248.47(4)
_cod_database_code               1561594
_shelx_estimated_absorpt_t_min   0.371
_shelx_estimated_absorpt_t_max   0.538
_shelxl_version_number           2013-4
_shelx_res_checksum              4131
_shelx_hkl_checksum              39198