Is CH3NH3PbI3 Polar?
G, Sharada; Mahale, Pratibha; Kore, Bhushan P.; Mukherjee, Somdutta; Pavan, Mysore S.; De, Chandan; Ghara, Somnath; Sundaresan, A.; Pandey, Anshu; Guru Row, Tayur N.; Sarma, D. D.; The journal of physical chemistry letters 7 (2016) 2412–2419; doi:10.1021/acs.jpclett.6b00803

data_8000233
_publ_section_title
;
 Is CH3NH3PbI3 Polar?
;
_journal_issue                   13
_journal_name_full               'The journal of physical chemistry letters'
_journal_page_first              2412
_journal_page_last               2419
_journal_paper_doi               10.1021/acs.jpclett.6b00803
_journal_volume                  7
_journal_year                    2016
_chemical_formula_sum            'I6 N8 Pb2'
_chemical_formula_weight         1287.88
_space_group_crystal_system      tetragonal
_space_group_IT_number           140
_space_group_name_Hall           '-I 4 2c'
_space_group_name_H-M_alt        'I 4/m c m'
_symmetry_space_group_name_Hall  '-I 4 2c'
_symmetry_space_group_name_H-M   'I 4/m c m'
_audit_creation_method           SHELXL-2013
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            2
_cell_length_a                   8.8117(8)
_cell_length_b                   8.8117(8)
_cell_length_c                   12.674(2)
_cell_measurement_reflns_used    1415
_cell_measurement_temperature    180(2)
_cell_measurement_theta_max      30.4920
_cell_measurement_theta_min      3.2710
_cell_volume                     984.1(2)
_computing_structure_refinement  'SHELXL-2013 (Sheldrick, 2013)'
_diffrn_ambient_temperature      180(2)
_diffrn_detector                 'CCD plate'
_diffrn_detector_area_resol_mean 8.0419
_diffrn_detector_type            Eos
_diffrn_measured_fraction_theta_full 0.996
_diffrn_measured_fraction_theta_max 0.998
_diffrn_measurement_device       'four-circle diffractometer'
_diffrn_measurement_device_type  'Xcalibur, Eos, Nova'
_diffrn_radiation_monochromator  mirror
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0885
_diffrn_reflns_av_unetI/netI     0.0518
_diffrn_reflns_Laue_measured_fraction_full 0.996
_diffrn_reflns_Laue_measured_fraction_max 0.998
_diffrn_reflns_limit_h_max       12
_diffrn_reflns_limit_h_min       -10
_diffrn_reflns_limit_k_max       12
_diffrn_reflns_limit_k_min       -12
_diffrn_reflns_limit_l_max       17
_diffrn_reflns_limit_l_min       -17
_diffrn_reflns_number            2814
_diffrn_reflns_point_group_measured_fraction_full 0.996
_diffrn_reflns_point_group_measured_fraction_max 0.998
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         30.559
_diffrn_reflns_theta_min         3.215
_exptl_absorpt_coefficient_mu    26.489
_exptl_absorpt_correction_T_max  0.445
_exptl_absorpt_correction_T_min  0.198
_exptl_absorpt_correction_type   analytical
_exptl_absorpt_process_details
;
CrysAlisPro, Agilent Technologies,
Version 1.171.37.31 (release 14-01-2014 CrysAlis171 .NET)
(compiled Jan 14 2014,18:38:05)
Analytical numeric absorption correction using a multifaceted crystal
            model based on expressions derived by R.C. Clark & J.S. Reid.
(Clark, R. C. & Reid, J. S. (1995). Acta Cryst. A51, 887-897)
Empirical absorption correction using spherical harmonics,
 implemented in SCALE3 ABSPACK scaling algorithm.
;
_exptl_crystal_colour            black
_exptl_crystal_density_diffrn    4.346
_exptl_crystal_description       block
_exptl_crystal_F_000             1076
_exptl_crystal_size_max          0.0966
_exptl_crystal_size_mid          0.0598
_exptl_crystal_size_min          0.0418
_refine_diff_density_max         4.74
_refine_diff_density_min         -3.89
_refine_diff_density_rms         0.596
_refine_ls_extinction_coef       0.0013(4)
_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   0.972
_refine_ls_hydrogen_treatment    undef
_refine_ls_matrix_type           full
_refine_ls_number_parameters     11
_refine_ls_number_reflns         429
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      0.972
_refine_ls_R_factor_all          0.0684
_refine_ls_R_factor_gt           0.0612
_refine_ls_shift/su_max          0.004
_refine_ls_shift/su_mean         0.001
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
;
 w=1/[\s^2^(Fo^2^)+(0.1205P)^2^+132.1827P]
 where P=(Fo^2^+2Fc^2^)/3
;
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1898
_refine_ls_wR_factor_ref         0.1962
_reflns_Friedel_coverage         0.000
_reflns_number_gt                385
_reflns_number_total             429
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            jz6b00803_si_003.cif
_cod_data_source_block           n
_cod_database_code               8000233
_shelxl_version_number           2013-2
_shelx_res_checksum              92411
_shelx_hkl_checksum              41925