Crystal engineering in the <i>gem</i>-alkynol family: the key role of water in the structure of 2,3,5,6-tetrabromo-<i>trans</i>-1,4-diethynyl-cyclohexa-2,5-diene-1,4-diol dihydrate determined by X-ray and neutron diffraction at 150K
Bilton, Clair; Howard, Judith A. K.; Madhavi, N. N. L.; Desiraju, Gautam R.; Allen, Frank H.; Wilson, Chick C.; Acta Crystallographica Section B 57 (2001) 560–566; doi:10.1107/S0108768101008412

data_2103684
_publ_section_title
;
 Crystal engineering in the <i>gem</i>-alkynol family: the key role of
 water in the structure of
 2,3,5,6-tetrabromo-<i>trans</i>-1,4-diethynyl-cyclohexa-2,5-diene-1,4-diol
 dihydrate determined by X-ray and neutron diffraction at 150K
;
_journal_issue                   4
_journal_name_full               'Acta Crystallographica Section B'
_journal_page_first              560
_journal_page_last               566
_journal_paper_doi               10.1107/S0108768101008412
_journal_volume                  57
_journal_year                    2001
_chemical_formula_moiety         'C10 H4 Br4 O2, 2(H2 O)'
_chemical_formula_sum            'C10 H8 Br4 O4'
_chemical_formula_weight         511.80
_space_group_IT_number           138
_symmetry_cell_setting           tetragonal
_symmetry_space_group_name_Hall  '-P 4ac 2ac'
_symmetry_space_group_name_H-M   'P 42/n c m :2'
_audit_creation_method           SHELXL-97
_cell_angle_alpha                90.00
_cell_angle_beta                 90.00
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   12.6551(18)
_cell_length_b                   12.6551(18)
_cell_length_c                   8.7340(17)
_cell_measurement_temperature    150
_cell_volume                     1398.8(4)
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      150
_diffrn_measured_fraction_theta_full .280
_diffrn_measured_fraction_theta_max .280
_diffrn_measurement_device_type  `SXD'
_diffrn_measurement_method       'time-of-flight LAUE diffraction'
_diffrn_radiation_monochromator  none
_diffrn_radiation_probe          neutron
_diffrn_radiation_source         'ISIS spallation source'
_diffrn_radiation_type           neutron
_diffrn_radiation_wavelength     0.5-5.0
_diffrn_reflns_av_R_equivalents  .0000
_diffrn_reflns_av_sigmaI/netI    .0241
_diffrn_reflns_limit_h_max       28
_diffrn_reflns_limit_h_min       0
_diffrn_reflns_limit_k_max       18
_diffrn_reflns_limit_k_min       0
_diffrn_reflns_limit_l_max       21
_diffrn_reflns_limit_l_min       0
_diffrn_reflns_number            1654
_diffrn_reflns_theta_full        62.64
_diffrn_reflns_theta_max         62.64
_diffrn_reflns_theta_min         2.28
_exptl_absorpt_coefficient_mu    .000
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    2.429
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             348
_exptl_crystal_size_max          3
_exptl_crystal_size_mid          2
_exptl_crystal_size_min          2
_refine_diff_density_max         2.284
_refine_diff_density_min         -1.399
_refine_ls_extinction_method     'Becker-Coppens Lorentzian model'
_refine_ls_goodness_of_fit_ref   6.188
_refine_ls_hydrogen_treatment    refall
_refine_ls_matrix_type           full
_refine_ls_number_parameters     70
_refine_ls_number_reflns         1654
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      6.188
_refine_ls_R_factor_all          .0607
_refine_ls_R_factor_gt           .0607
_refine_ls_shift/su_max          .000
_refine_ls_shift/su_mean         .000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0000P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_ref         .0819
_reflns_number_gt                1654
_reflns_number_total             1654
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            bm0041.cif
_cod_data_source_block           nlmbrN
_cod_original_sg_symbol_H-M      P4(2)/ncm
_cod_database_code               2103684