Hybrid germanium iodide perovskite semiconductors: active lone pairs, structural distortions, direct and indirect energy gaps, and strong nonlinear optical properties.
Stoumpos, Constantinos C.; Frazer, Laszlo; Clark, Daniel J.; Kim, Yong Soo; Rhim, Sonny H.; Freeman, Arthur J.; Ketterson, John B.; Jang, Joon I.; Kanatzidis, Mercouri G.; Journal of the American Chemical Society 137 (2015) 6804–6819; doi:10.1021/jacs.5b01025

data_4123711
_publ_section_title
;
 Hybrid germanium iodide perovskite semiconductors: active lone pairs,
 structural distortions, direct and indirect energy gaps, and strong
 nonlinear optical properties.
;
_journal_issue                   21
_journal_name_full               'Journal of the American Chemical Society'
_journal_page_first              6804
_journal_page_last               6819
_journal_paper_doi               10.1021/jacs.5b01025
_journal_volume                  137
_journal_year                    2015
_chemical_formula_moiety         CH3NH3GeI3
_chemical_formula_sum            'C H6 Ge I3 N'
_chemical_formula_weight         485.36
_chemical_name_common            Methylammonium_Germanium_Iodide
_space_group_IT_number           160
_symmetry_cell_setting           trigonal
_symmetry_space_group_name_Hall  'R 3 -2"'
_symmetry_space_group_name_H-M   'R 3 m :H'
_atom_sites_solution_hydrogens   none
_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                120.00
_cell_formula_units_Z            3
_cell_length_a                   8.5534(13)
_cell_length_b                   8.5534(13)
_cell_length_c                   11.162(2)
_cell_measurement_reflns_used    2316
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      27.39
_cell_measurement_theta_min      3.30
_cell_volume                     707.2(2)
_diffrn_ambient_temperature      293(2)
_diffrn_detector                 'image plate (34 cm diameter)'
_diffrn_detector_area_resol_mean 6.67
_diffrn_detector_type            STOE
_diffrn_measured_fraction_theta_full 0.985
_diffrn_measured_fraction_theta_max 0.985
_diffrn_measurement_device       '2-circle goniometer'
_diffrn_measurement_device_type  'STOE IPDS 2'
_diffrn_measurement_method       'rotation method'
_diffrn_radiation_collimation    '0.5 mm diameter, monocapillary'
_diffrn_radiation_monochromator  'plane graphite'
_diffrn_radiation_polarisn_norm  0
_diffrn_radiation_type           'Mo K\a'
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0359
_diffrn_reflns_av_sigmaI/netI    0.0213
_diffrn_reflns_limit_h_max       10
_diffrn_reflns_limit_h_min       -9
_diffrn_reflns_limit_k_max       11
_diffrn_reflns_limit_k_min       -11
_diffrn_reflns_limit_l_max       15
_diffrn_reflns_limit_l_min       -15
_diffrn_reflns_number            2203
_diffrn_reflns_theta_full        29.05
_diffrn_reflns_theta_max         29.05
_diffrn_reflns_theta_min         3.30
_diffrn_source
'sealed X-ray tube, 12 x 0.4 mm long-fine focus'
_diffrn_source_current           30
_diffrn_source_power             1.20
_diffrn_source_voltage           40
_exptl_absorpt_coefficient_mu    12.983
_exptl_absorpt_correction_T_max  0.5674
_exptl_absorpt_correction_T_min  0.2546
_exptl_absorpt_correction_type   integration
_exptl_crystal_colour            Red
_exptl_crystal_density_diffrn    3.419
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       'Hexagonal needle'
_exptl_crystal_F_000             630
_exptl_crystal_size_max          0.057
_exptl_crystal_size_mid          0.031
_exptl_crystal_size_min          0.018
_refine_diff_density_max         0.668
_refine_diff_density_min         -0.774
_refine_diff_density_rms         0.109
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   0.00(6)
_refine_ls_extinction_coef       0.0027(3)
_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   1.366
_refine_ls_hydrogen_treatment    none
_refine_ls_matrix_type           full
_refine_ls_number_parameters     16
_refine_ls_number_reflns         506
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.364
_refine_ls_R_factor_all          0.0382
_refine_ls_R_factor_gt           0.0366
_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^)+(0.0089P)^2^+3.3356P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0533
_refine_ls_wR_factor_ref         0.0536
_reflns_number_gt                494
_reflns_number_total             506
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ja5b01025_si_002.cif
_cod_data_source_block           2
_cod_depositor_comments
;
The following automatic conversions were performed:

'_symmetry_cell_setting' value 'Trigonal' changed to 'trigonal'
according to
/usr/data/users/saulius/crontab/automatic-downloads/rss-feeds/ACS/lib/dictionaries/cif_core.dic
dictionary named 'cif_core.dic' version 2.4.2 from 2011-04-26.

Automatic conversion script
Id: cif_fix_values 3271 2015-04-21 07:52:19Z andrius 

 Adding full bibliography for 4123710--4123716.cif.
;
_cod_original_sg_symbol_H-M      R3m
_cod_database_code               4123711