Reinvestigation of the low-temperature form of Ag~2~Se (naumannite) based on single-crystal data
Jaemin Yu; Hoseop Yun; Acta Crystallographica, Section E 67 (2011) i45–i45; doi:10.1107/S1600536811028534

data_2230972
_publ_section_title
;
 Reinvestigation of the low-temperature form of Ag~2~Se (naumannite) based
 on single-crystal data
;
_journal_coeditor_code           WM2506
_journal_issue                   9
_journal_name_full               'Acta Crystallographica, Section E'
_journal_page_first              i45
_journal_page_last               i45
_journal_paper_doi               10.1107/S1600536811028534
_journal_volume                  67
_journal_year                    2011
_chemical_formula_iupac          'Ag2 Se'
_chemical_formula_moiety         'Ag2 Se'
_chemical_formula_sum            'Ag2 Se'
_chemical_formula_weight         294.7
_chemical_name_systematic
;
disilver(I) selenide
;
_space_group_IT_number           19
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  'P 2ac 2ab'
_symmetry_space_group_name_H-M   'P 21 21 21'
_audit_creation_method           'WinGX routine CIF_UPDATE'
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   4.3359(8)
_cell_length_b                   7.0700(10)
_cell_length_c                   7.7740(10)
_cell_measurement_reflns_used    1738
_cell_measurement_temperature    290.0(10)
_cell_measurement_theta_max      27.50
_cell_measurement_theta_min      3.40
_cell_volume                     238.31(6)
_computing_cell_refinement       'RAPID-AUTO (Rigaku, 2006)'
_computing_data_collection       'RAPID-AUTO (Rigaku, 2006)'
_computing_data_reduction        'RAPID-AUTO (Rigaku, 2006)'
_computing_molecular_graphics
'locally modified version of ORTEP (Johnson, 1965)'
_computing_publication_material  'WinGX (Farrugia, 1999)'
_computing_structure_refinement  'SHELXL97 (Sheldrick, 2008)'
_computing_structure_solution    'SHELXS97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      290.0(10)
_diffrn_measured_fraction_theta_full 1
_diffrn_measured_fraction_theta_max 1
_diffrn_measurement_device_type  'Rigaku R-AXIS RAPID'
_diffrn_measurement_method       \w
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.057
_diffrn_reflns_limit_h_max       5
_diffrn_reflns_limit_h_min       -5
_diffrn_reflns_limit_k_max       8
_diffrn_reflns_limit_k_min       -8
_diffrn_reflns_limit_l_max       9
_diffrn_reflns_limit_l_min       -9
_diffrn_reflns_number            1981
_diffrn_reflns_theta_full        25.99
_diffrn_reflns_theta_max         25.99
_diffrn_reflns_theta_min         3.9
_diffrn_standards_decay_%        0
_diffrn_standards_interval_count 0
_diffrn_standards_interval_time  0
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    31.267
_exptl_absorpt_correction_T_max  0.278
_exptl_absorpt_correction_T_min  0.053
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   '(NUMABS; Higashi, 2000)'
_exptl_crystal_colour            black
_exptl_crystal_density_diffrn    8.213
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       needle
_exptl_crystal_F_000             512
_exptl_crystal_size_max          0.300
_exptl_crystal_size_mid          0.040
_exptl_crystal_size_min          0.020
_refine_diff_density_max         1.192
_refine_diff_density_min         -1.069
_refine_ls_abs_structure_details 'Flack (1983), 167 Friedel pairs'
_refine_ls_abs_structure_Flack   0.34(4)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.135
_refine_ls_matrix_type           full
_refine_ls_number_parameters     29
_refine_ls_number_reflns         464
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.135
_refine_ls_R_factor_gt           0.0311
_refine_ls_shift/su_max          0
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0329P)^2^+1.0072P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_ref         0.0799
_reflns_number_gt                447
_reflns_number_total             464
_reflns_threshold_expression     I>2sigma(I)
_cod_data_source_file            wm2506.cif
_cod_data_source_block           I
_cod_original_cell_volume        238.34(7)
_cod_database_code               2230972
_cod_database_fobs_code          2230972