Polymorphism of a polymer precursor: metastable glycolide polymorph recovered via large scale high-pressure experiments
Hutchison, Ian B.; Delori, Amit; Wang, Xiao; Kamenev, Konstantin V.; Urquhart, Andrew J.; Oswald, Iain D. H.; CrystEngComm 17 (2015) 1778–; doi:10.1039/C5CE00119F

data_7219346
_publ_section_title
;
 Polymorphism of a polymer precursor: metastable glycolide polymorph
 recovered via large scale high-pressure experiments
;
_journal_issue                   8
_journal_name_full               CrystEngComm
_journal_page_first              1778
_journal_paper_doi               10.1039/C5CE00119F
_journal_volume                  17
_journal_year                    2015
_chemical_formula_moiety         'C4 H4 O4'
_chemical_formula_sum            'C4 H4 O4'
_chemical_formula_weight         116.07
_chemical_name_common            '1,4-Dioxane-2,5-dione '
_chemical_name_systematic        Glycolide
_chemical_properties_physical    Heat-sensitive
_space_group_IT_number           61
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  '-P 2ac 2ab'
_symmetry_space_group_name_H-M   'P b c a'
_atom_sites_solution_hydrogens   difmap
_atom_sites_solution_primary     direct
_audit_update_record
;
2015-01-14 deposited with the CCDC.
2015-01-20 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   5.2399(2)
_cell_length_b                   7.4388(3)
_cell_length_c                   11.7763(4)
_cell_measurement_reflns_used    4704
_cell_measurement_temperature    293
_cell_measurement_theta_max      26
_cell_measurement_theta_min      5
_cell_volume                     459.02(3)
_computing_cell_refinement       'Apex2 (Bruker AXS, 2006)'
_computing_data_collection       'Apex2 (Bruker AXS, 2006)'
_computing_data_reduction        'Apex2 (Bruker AXS, 2006)'
_computing_molecular_graphics    'CAMERON (Watkin et al., 1996)'
_computing_publication_material  'CRYSTALS (Betteridge et al., 2003)'
_computing_structure_refinement  'CRYSTALS (Betteridge et al., 2003)'
_computing_structure_solution    'SIR92 (Altomare et al., 1994)'
_diffrn_ambient_temperature      293
_diffrn_measured_fraction_theta_full 0.996
_diffrn_measured_fraction_theta_max 0.994
_diffrn_measurement_device       Area
_diffrn_measurement_device_type  'Bruker Kappa Apex2'
_diffrn_measurement_method       '\f & \w scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_type           'Mo K\a'
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.036
_diffrn_reflns_limit_h_max       6
_diffrn_reflns_limit_h_min       -6
_diffrn_reflns_limit_k_max       9
_diffrn_reflns_limit_k_min       -9
_diffrn_reflns_limit_l_max       14
_diffrn_reflns_limit_l_min       -14
_diffrn_reflns_number            7121
_diffrn_reflns_theta_full        25.863
_diffrn_reflns_theta_max         26.391
_diffrn_reflns_theta_min         5.064
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.156
_exptl_absorpt_correction_T_max  0.97
_exptl_absorpt_correction_T_min  0.69
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'SADABS (Siemens, 1996)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.680
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       plate
_exptl_crystal_F_000             240
_exptl_crystal_recrystallization_method
'Re-crystallisation from solvent: Acetone after download from high pressure'
_exptl_crystal_size_max          0.420
_exptl_crystal_size_mid          0.350
_exptl_crystal_size_min          0.210
_refine_diff_density_max         0.14
_refine_diff_density_min         -0.19
_refine_ls_extinction_method     None
_refine_ls_goodness_of_fit_ref   0.9594
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     55
_refine_ls_number_reflns         470
_refine_ls_number_restraints     38
_refine_ls_R_factor_all          0.0424
_refine_ls_R_factor_gt           0.0417
_refine_ls_shift/su_max          0.0024279
_refine_ls_shift/su_mean         0.0004383
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
;
 Method= Modified Sheldrick 
 w=1/[\s^2^(F^2^) + ( 0.03P)^2^ + 0.45P] 
 ,where P=(max(Fo^2^,0) + 2Fc^2^)/3 
;
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_all         0.0929
_refine_ls_wR_factor_gt          0.0921
_refine_ls_wR_factor_ref         0.0929
_reflns_limit_h_max              6
_reflns_limit_h_min              0
_reflns_limit_k_max              9
_reflns_limit_k_min              0
_reflns_limit_l_max              14
_reflns_limit_l_min              0
_reflns_number_gt                456
_reflns_number_total             470
_reflns_threshold_expression     I>2.0\s(I)
_oxford_diffrn_Wilson_B_factor   3.79
_oxford_diffrn_Wilson_scale      4.25
_oxford_refine_ls_r_factor_ref   0.0424
_oxford_refine_ls_scale          0.499(2)
_oxford_reflns_number_all        470
_oxford_reflns_threshold_expression_ref I>-3.0\s(I)
_cod_data_source_file            c5ce00119f2.cif
_cod_data_source_block           Form2
_cod_depositor_comments
'Adding full bibliography for 7219345--7219346.cif.'
_cod_original_cell_volume        459.023(16)
_cod_original_sg_symbol_H-M      'P b c a '
_cod_database_code               7219346