New strategy for designing promising mid-infrared nonlinear optical materials: narrowing the band gap for large nonlinear optical efficiencies and reducing the thermal effect for a high laser-induced damage threshold.
Li, Shu-Fang; Jiang, Xiao-Ming; Fan, Yu-Hang; Liu, Bin-Wen; Zeng, Hui-Yi; Guo, Guo-Cong; Chemical science 9 (2018) 5700–5708; doi:10.1039/c8sc01210e

data_1549420
_publ_section_title
;
 New strategy for designing promising mid-infrared nonlinear optical
 materials: narrowing the band gap for large nonlinear optical
 efficiencies and reducing the thermal effect for a high laser-induced
 damage threshold.
;
_journal_issue                   26
_journal_name_full               'Chemical science'
_journal_page_first              5700
_journal_page_last               5708
_journal_paper_doi               10.1039/c8sc01210e
_journal_volume                  9
_journal_year                    2018
_chemical_formula_sum            'Ga2 Ge Na2 Se6'
_chemical_formula_weight         731.77
_chemical_name_systematic        Na2Ga2GeSe6
_space_group_crystal_system      orthorhombic
_space_group_IT_number           43
_space_group_name_Hall           'F 2 -2d'
_space_group_name_H-M_alt        'F d d 2'
_symmetry_space_group_name_Hall  'F 2 -2d'
_symmetry_space_group_name_H-M   'F d d 2'
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_audit_update_record
;
2018-05-10 deposited with the CCDC.
2018-05-16 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            8
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_cell_length_c                   7.585(3)
_cell_measurement_temperature    293(2)
_cell_volume                     2352.0(14)
_computing_structure_refinement  'SHELXL-2013 (Sheldrick, 2013)'
_diffrn_ambient_temperature      293(2)
_diffrn_measured_fraction_theta_full 0.997
_diffrn_measured_fraction_theta_max 0.998
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0555
_diffrn_reflns_av_unetI/netI     0.0408
_diffrn_reflns_Laue_measured_fraction_full 0.997
_diffrn_reflns_Laue_measured_fraction_max 0.998
_diffrn_reflns_limit_h_max       12
_diffrn_reflns_limit_h_min       -15
_diffrn_reflns_limit_k_max       28
_diffrn_reflns_limit_k_min       -28
_diffrn_reflns_limit_l_max       7
_diffrn_reflns_limit_l_min       -9
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_diffrn_reflns_point_group_measured_fraction_full 0.886
_diffrn_reflns_point_group_measured_fraction_max 0.882
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_diffrn_reflns_theta_max         25.457
_diffrn_reflns_theta_min         3.225
_exptl_absorpt_coefficient_mu    25.671
_exptl_crystal_density_diffrn    4.133
_exptl_crystal_F_000             2560
_refine_diff_density_max         0.554
_refine_diff_density_min         -0.984
_refine_diff_density_rms         0.146
_refine_ls_abs_structure_details
;
 Flack x determined using 330 quotients [(I+)-(I-)]/[(I+)+(I-)]
 (Parsons and Flack (2004), Acta Cryst. A60, s61).
;
_refine_ls_abs_structure_Flack   1.00(4)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.134
_refine_ls_hydrogen_treatment    undef
_refine_ls_matrix_type           full
_refine_ls_number_parameters     51
_refine_ls_number_reflns         956
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.134
_refine_ls_R_factor_all          0.0318
_refine_ls_R_factor_gt           0.0272
_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^)+(0.0248P)^2^]
 where P=(Fo^2^+2Fc^2^)/3
;
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0567
_refine_ls_wR_factor_ref         0.0576
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_reflns_Friedel_fraction_full    0.756
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_reflns_number_gt                888
_reflns_number_total             956
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            c8sc01210e2.cif
_cod_data_source_block           1_CCDC1
_cod_depositor_comments
'Adding full bibliography for 1549419--1549422.cif.'
_cod_database_code               1549420
_shelxl_version_number           2013-2
_shelx_res_checksum              50486