Two Polymorphic Forms of 3-Hydroxy-2-methyl-4<i>H</i>-pyran-4-one (Maltol)
Burgess, J.; Fawcett, J.; Russell, D. R.; Hider, R. C.; Hossain, M. B.; Stoner, C. R.; van der Helm, D.; Acta Crystallographica Section C 52 (1996) 2917–2920; doi:10.1107/S0108270196007081

data_2005588
_publ_section_title
;
 Two Polymorphic Forms of 3-Hydroxy-2-methyl-4<i>H</i>-pyran-4-one
 (Maltol)
;
_journal_issue                   11
_journal_name_full               'Acta Crystallographica Section C'
_journal_page_first              2917
_journal_page_last               2920
_journal_paper_doi               10.1107/S0108270196007081
_journal_volume                  52
_journal_year                    1996
_chemical_formula_iupac          'C6 H6 O3'
_chemical_formula_moiety         'C6 H6 O3'
_chemical_formula_structural     'C5 H2 O (CH3) (OH) (O)'
_chemical_formula_sum            'C6 H6 O3'
_chemical_formula_weight         126.11
_chemical_name_common            Maltol
_space_group_IT_number           14
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-P 2ybc'
_symmetry_space_group_name_H-M   'P 1 21/c 1'
_audit_creation_method           SHELXL
_cell_angle_alpha                90.00
_cell_angle_beta                 109.79(3)
_cell_angle_gamma                90.00
_cell_formula_units_Z            12
_cell_length_a                   7.166(2)
_cell_length_b                   35.909(10)
_cell_length_c                   6.982(2)
_cell_measurement_reflns_used    24
_cell_measurement_temperature    163(2)
_cell_measurement_theta_max      25
_cell_measurement_theta_min      15
_cell_volume                     1690.5(9)
_computing_cell_refinement       'local program'
_computing_data_collection       'CAD4 Software (Enraf-Nonius, 1989)'
_computing_data_reduction        'local program'
_computing_molecular_graphics    'SHELXTL/PC XP'
_computing_publication_material  SHELXTL/PC
_computing_structure_refinement  'SHELXL93 (Sheldrick, 1993)'
_computing_structure_solution    'SHELXS86 (Sheldrick, 1990)'
_diffrn_ambient_temperature      163(2)
_diffrn_measurement_device       'Enraf-Nonius CAD-4'
_diffrn_measurement_method       \w-2\q
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           CuK\a
_diffrn_radiation_wavelength     1.54178
_diffrn_reflns_av_R_equivalents  0.0000
_diffrn_reflns_av_sigmaI/netI    0.0456
_diffrn_reflns_limit_h_max       8
_diffrn_reflns_limit_h_min       -8
_diffrn_reflns_limit_k_max       44
_diffrn_reflns_limit_k_min       0
_diffrn_reflns_limit_l_max       8
_diffrn_reflns_limit_l_min       0
_diffrn_reflns_number            3467
_diffrn_reflns_theta_max         74.98
_diffrn_reflns_theta_min         2.46
_diffrn_standards_decay_%        <1.5
_diffrn_standards_interval_count 200
_diffrn_standards_number         3
_exptl_absorpt_coefficient_mu    1.033
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.486
_exptl_crystal_density_method    none
_exptl_crystal_description       rod
_exptl_crystal_F_000             792
_exptl_crystal_size_max          0.40
_exptl_crystal_size_mid          0.15
_exptl_crystal_size_min          0.10
_refine_diff_density_max         0.28
_refine_diff_density_min         -0.31
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_all   1.071
_refine_ls_goodness_of_fit_obs   1.078
_refine_ls_hydrogen_treatment
'H atoms treated as riding, U~iso~ values refined'
_refine_ls_matrix_type           full
_refine_ls_number_parameters     244
_refine_ls_number_reflns         3467
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.071
_refine_ls_restrained_S_obs      1.078
_refine_ls_R_factor_all          0.0581
_refine_ls_R_factor_obs          0.0434
_refine_ls_shift/esd_max         0.007
_refine_ls_shift/esd_mean        0.001
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w = 1/[\s^2^(Fo^2^)+(0.067P)^2^+0.334P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_all         0.1274
_refine_ls_wR_factor_obs         0.1151
_reflns_number_observed          2830
_reflns_number_total             3467
_reflns_observed_criterion       >2sigma(I)
_cod_data_source_file            bm1083.cif
_cod_data_source_block           2
_cod_depositor_comments
;
The following automatic conversions were performed:
'_symmetry_cell_setting' value 'Monoclinic' changed to 'monoclinic'
according to '/home/saulius/struct/CIF-dictionaries/cif_core.dic'
dictionary named 'cif_core.dic' version 2.4.1 from 2010-06-29.

Automatic conversion script
Id: cif_fix_enum 1527 2010-12-29 10:47:43Z saulius 

The following automatic conversions were performed:

'_symmetry_cell_setting' value 'Monoclinic' changed to 'monoclinic'
according to /home/saulius/struct/CIF-dictionaries/cif_core.dic
dictionary named 'cif_core.dic' version 2.4.1 from 2010-06-29.

Automatic conversion script
Id: cif_fix_values 1715 2011-07-08 13:25:40Z adriana 

The following automatic conversions were performed:

'_refine_ls_weighting_scheme' value 'calc w =
1/[\s^2^(Fo^2^)+(0.067P)^2^+0.334P] where P=(Fo^2^+2Fc^2^)/3' was
changed to 'calc'. New tag '_refine_ls_weighting_details' was
created. The value of the new tag was set to 'w =
1/[\s^2^(Fo^2^)+(0.067P)^2^+0.334P] where P=(Fo^2^+2Fc^2^)/3'.

Automatic conversion script
Id: cif_fix_values 3143 2015-03-26 13:38:13Z robertas 
;
_cod_original_cell_volume        1690.5(8)
_cod_original_sg_symbol_H-M      'P 21/c'
_cod_database_code               2005588