A new polymorph of physcion
Hopf, Henning; Jones, Peter G.; Goclik, Eva; Aust, Pauline; Rödiger, Johanna; Acta Crystallographica Section C 68 (2012) o317–o319; doi:10.1107/S010827011203020X

data_2018580
_publ_section_title
;
 A new polymorph of physcion
;
_journal_coeditor_code           MX3079
_journal_issue                   8
_journal_name_full               'Acta Crystallographica Section C'
_journal_page_first              o317
_journal_page_last               o319
_journal_paper_doi               10.1107/S010827011203020X
_journal_volume                  68
_journal_year                    2012
_chemical_formula_iupac          'C16 H12 O5'
_chemical_formula_moiety         'C16 H12 O5'
_chemical_formula_sum            'C16 H12 O5'
_chemical_formula_weight         284.26
_chemical_name_common            physcion
_chemical_name_systematic
;
7-methoxy-2-methyl-4,5-dihydroxyanthracene-9,10-dione
;
_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'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_cell_angle_alpha                90.00
_cell_angle_beta                 95.370(4)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   6.1986(3)
_cell_length_b                   24.5470(12)
_cell_length_c                   8.1004(4)
_cell_measurement_reflns_used    17945
_cell_measurement_temperature    130(2)
_cell_measurement_theta_max      75.6800
_cell_measurement_theta_min      3.5982
_cell_volume                     1227.12(10)
_computing_cell_refinement
;
CrysAlis PRO (Agilent, 2012)
;
_computing_data_collection
;
CrysAlis PRO (Agilent, 2012)
;
_computing_data_reduction
;
CrysAlis PRO (Agilent, 2012)
;
_computing_molecular_graphics    'XP (Siemens, 1994)'
_computing_publication_material  'SHELXL97 (Sheldrick, 2008)'
_computing_structure_refinement  'SHELXL97 (Sheldrick, 2008)'
_computing_structure_solution    'SHELXS97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      130(2)
_diffrn_detector_area_resol_mean 10.3543
_diffrn_measured_fraction_theta_full 0.998
_diffrn_measured_fraction_theta_max 0.996
_diffrn_measurement_device_type  'Agilent Technologies Xcalibur (Atlas, Nova)'
_diffrn_measurement_method       ' \w scan'
_diffrn_radiation_monochromator  mirror
_diffrn_radiation_source         'Nova (Cu) X-ray Source'
_diffrn_radiation_type           CuK\a
_diffrn_radiation_wavelength     1.54184
_diffrn_reflns_av_R_equivalents  0.0356
_diffrn_reflns_av_sigmaI/netI    0.0103
_diffrn_reflns_limit_h_max       7
_diffrn_reflns_limit_h_min       -7
_diffrn_reflns_limit_k_max       30
_diffrn_reflns_limit_k_min       -30
_diffrn_reflns_limit_l_max       10
_diffrn_reflns_limit_l_min       -10
_diffrn_reflns_number            43156
_diffrn_reflns_theta_full        75.00
_diffrn_reflns_theta_max         75.87
_diffrn_reflns_theta_min         3.60
_exptl_absorpt_coefficient_mu    0.967
_exptl_absorpt_correction_T_max  1.00000
_exptl_absorpt_correction_T_min  0.64608
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   '(CrysAlis PRO; Agilent, 2012)'
_exptl_crystal_colour            orange
_exptl_crystal_density_diffrn    1.539
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       plate
_exptl_crystal_F_000             592
_exptl_crystal_size_max          0.25
_exptl_crystal_size_mid          0.10
_exptl_crystal_size_min          0.04
_refine_diff_density_max         0.311
_refine_diff_density_min         -0.246
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.052
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     200
_refine_ls_number_reflns         2553
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.052
_refine_ls_R_factor_all          0.0468
_refine_ls_R_factor_gt           0.0432
_refine_ls_shift/su_max          0.001
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0676P)^2^+0.6508P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1219
_refine_ls_wR_factor_ref         0.1256
_reflns_number_gt                2314
_reflns_number_total             2553
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            mx3079.cif
_cod_data_source_block           I
_cod_original_sg_symbol_H-M      'P 21/c'
_cod_database_code               2018580
_cod_database_fobs_code          2018580