#------------------------------------------------------------------------------
#$Date: 2026-05-14 00:24:51 +0200 (Thu 14 de May de 2026) $
#$Revision: 305959 $
#$URL: svn://saulius.grazulis.lt/cod-secondary/cif/1/57/72/1577254.cif $
#------------------------------------------------------------------------------
#
# This file is available in the Crystallography Open Database (COD),
# http://www.crystallography.net/
#
# All data on this site have been placed in the public domain by the
# contributors.
#
data_1577254
loop_
_publ_author_name
'Lennox, Cameron B.'
'Taylor, Christopher'
'Huskić, Igor'
'Vainauskas, Jogirdas'
'Nickels, Christopher'
'Stein, Robin S.'
'Borchers, Tristan H.'
'Lutton Gething, A.R. Bonnie J.'
'Marrett, Joseph M.'
'Day, Graeme Matthew'
'Friščić, Tomislav'
_publ_section_title
;
 The elusive endo-product of the archetypal Diels-Alder reaction of furan
 and maleic anhydride -- observed in the solid state at last
;
_journal_name_full               'Chemical Science'
_journal_paper_doi               10.1039/D5SC06724C
_journal_year                    2026
_chemical_formula_moiety         '2(C8 H6 O4)'
_chemical_formula_sum            'C16 H12 O8'
_chemical_formula_weight         332.26
_chemical_name_systematic
'7-oxabicyclo(2.2.1)-5-heptene-2,3-dicarboxylic anhydride cocrystal'
_space_group_crystal_system      monoclinic
_space_group_IT_number           7
_space_group_name_Hall           'P -2yac'
_space_group_name_H-M_alt        'P 1 n 1'
_atom_sites_solution_hydrogens   geom
_audit_creation_date             2024-06-11
_audit_creation_method
;
Olex2 1.5
(compiled 2024.01.12 svn.r2f8d729c for OlexSys, GUI svn.r6928)
;
_audit_update_record
;
2024-11-06 deposited with the CCDC.	2026-05-12 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 110.504(3)
_cell_angle_gamma                90
_cell_formula_units_Z            2
_cell_length_a                   11.9288(4)
_cell_length_b                   5.3945(2)
_cell_length_c                   11.9826(5)
_cell_measurement_reflns_used    2703
_cell_measurement_temperature    240
_cell_measurement_theta_max      144.6
_cell_measurement_theta_min      8.98
_cell_volume                     722.23(5)
_computing_cell_refinement       'SAINT V8.35A, Bruker-AXS'
_computing_data_collection       'APEX 2, Bruker-AXS'
_computing_data_reduction        'SAINT V8.35A, Bruker-AXS'
_computing_molecular_graphics    'Olex2 1.5 (Dolomanov et al., 2009)'
_computing_publication_material  'Olex2 1.5 (Dolomanov et al., 2009)'
_computing_structure_refinement  'SHELXL 2018/3 (Sheldrick, 2015)'
_computing_structure_solution    'olex2.solve 1.5 (Bourhis et al., 2015)'
_diffrn_ambient_temperature      240.00
_diffrn_measured_fraction_theta_full 0.997
_diffrn_measured_fraction_theta_max 0.997
_diffrn_measurement_device_type  'Bruker PHOTON 100 CMOS'
_diffrn_measurement_method       'omega and f scans'
_diffrn_radiation_type           CuK\a
_diffrn_radiation_wavelength     1.54178
_diffrn_reflns_av_R_equivalents  0.0972
_diffrn_reflns_av_unetI/netI     0.1055
_diffrn_reflns_Laue_measured_fraction_full 0.997
_diffrn_reflns_Laue_measured_fraction_max 0.997
_diffrn_reflns_limit_h_max       14
_diffrn_reflns_limit_h_min       -14
_diffrn_reflns_limit_k_max       6
_diffrn_reflns_limit_k_min       -4
_diffrn_reflns_limit_l_max       14
_diffrn_reflns_limit_l_min       -14
_diffrn_reflns_number            6464
_diffrn_reflns_point_group_measured_fraction_full 0.957
_diffrn_reflns_point_group_measured_fraction_max 0.944
_diffrn_reflns_theta_full        67.679
_diffrn_reflns_theta_max         72.277
_diffrn_reflns_theta_min         4.501
_exptl_absorpt_coefficient_mu    1.074
_exptl_absorpt_correction_T_max  0.7536
_exptl_absorpt_correction_T_min  0.5041
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'SADABS-2012/1, G. Sheldrick'
_exptl_crystal_colour            colorless
_exptl_crystal_colour_lustre     clear
_exptl_crystal_density_diffrn    1.528
_exptl_crystal_description       rhombic
_exptl_crystal_F_000             344
_exptl_crystal_size_max          0.6
_exptl_crystal_size_mid          0.4
_exptl_crystal_size_min          0.4
_refine_diff_density_max         0.193
_refine_diff_density_min         -0.183
_refine_diff_density_rms         0.049
_refine_ls_abs_structure_details
;
 Flack x determined using 526 quotients [(I+)-(I-)]/[(I+)+(I-)]
 (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
;
_refine_ls_abs_structure_Flack   -0.1(4)
_refine_ls_extinction_coef       0.021(4)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4^
_refine_ls_extinction_method     'SHELXL-2018/3 (Sheldrick 2018)'
_refine_ls_goodness_of_fit_ref   1.056
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     218
_refine_ls_number_reflns         2703
_refine_ls_number_restraints     2
_refine_ls_restrained_S_all      1.055
_refine_ls_R_factor_all          0.1039
_refine_ls_R_factor_gt           0.0566
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[σ²(Fo²)+(0.0568P)²+0.0760P] where P=(Fo²+2Fc²)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1374
_refine_ls_wR_factor_ref         0.1771
_reflns_Friedel_coverage         0.889
_reflns_Friedel_fraction_full    0.917
_reflns_Friedel_fraction_max     0.890
_reflns_number_gt                1684
_reflns_number_total             2703
_reflns_threshold_expression     'I > 2σ(I)'
_cod_data_source_file            d5sc06724c7.cif
_cod_data_source_block           (endo-1)(exo-1)-240K
_cod_database_code               1577254
_shelx_shelxl_version_number     2018/3
_shelx_space_group_comment
;
The symmetry employed for this shelxl refinement is uniquely defined
by the following loop, which should always be used as a source of
symmetry information in preference to the above space-group names.
They are only intended as comments.
;
_shelx_estimated_absorpt_t_max   0.673
_shelx_estimated_absorpt_t_min   0.565
_olex2_refinement_description
;
1.a Ternary CH refined with riding coordinates:
 C13(H13), C14(H14), C11(H11), C4(H4), C5(H5), C6(H6), C12(H12), C3(H3)
1.b Aromatic/amide H refined with riding coordinates:
 C15(H15), C7(H7), C16(H16), C8(H8)
;
_olex2_submission_special_instructions 'No special instructions were received'
loop_
_space_group_symop_operation_xyz
'x, y, z'
'x+1/2, -y, z+1/2'
loop_
_atom_site_label
_atom_site_type_symbol
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_U_iso_or_equiv
_atom_site_adp_type
_atom_site_occupancy
_atom_site_site_symmetry_order
_atom_site_calc_flag
_atom_site_refinement_flags_posn
_atom_site_refinement_flags_adp
_atom_site_refinement_flags_occupancy
_atom_site_disorder_assembly
_atom_site_disorder_group
O5 O 0.6592(5) 0.5436(10) 0.4992(5) 0.0603(13) Uani 1 1 d . . . . .
O6 O 0.6174(5) 0.4867(12) 0.3045(5) 0.0750(16) Uani 1 1 d . . . . .
O3 O 0.0716(5) 0.1325(13) 0.3400(5) 0.0804(19) Uani 1 1 d . . . . .
O8 O 0.9127(4) 0.3109(10) 0.5315(5) 0.0587(13) Uani 1 1 d . . . . .
O1 O 0.2680(5) 0.0860(10) 0.3823(5) 0.0623(13) Uani 1 1 d . . . . .
O4 O 0.2962(6) 0.6530(10) 0.6258(5) 0.0737(16) Uani 1 1 d . . . . .
O7 O 0.7175(6) 0.5087(14) 0.6959(6) 0.087(2) Uani 1 1 d . . . . .
O2 O 0.4647(5) 0.1313(12) 0.4376(7) 0.089(2) Uani 1 1 d . . . . .
C9 C 0.6596(6) 0.4030(14) 0.4025(7) 0.0538(17) Uani 1 1 d . . . . .
C2 C 0.1700(6) 0.2197(16) 0.3836(7) 0.0596(19) Uani 1 1 d . . . . .
C15 C 0.8993(6) -0.0971(15) 0.4754(8) 0.061(2) Uani 1 1 d . . . . .
H15 H 0.909769 -0.227976 0.428156 0.073 Uiso 1 1 calc R U . . .
C13 C 0.8478(6) 0.1526(14) 0.4336(6) 0.0536(17) Uani 1 1 d . . . . .
H13 H 0.850090 0.203617 0.355025 0.064 Uiso 1 1 calc R U . . .
C10 C 0.7105(6) 0.4153(16) 0.6030(7) 0.0600(19) Uani 1 1 d . . . . .
C14 C 0.8939(7) 0.1605(15) 0.6234(7) 0.0587(19) Uani 1 1 d . . . . .
H14 H 0.935817 0.216134 0.706327 0.070 Uiso 1 1 calc R U . . .
C7 C 0.3618(9) 0.2529(19) 0.6609(8) 0.080(3) Uani 1 1 d . . . . .
H7 H 0.416740 0.129011 0.700390 0.095 Uiso 1 1 calc R U . . .
C1 C 0.3710(6) 0.2206(16) 0.4313(7) 0.0598(19) Uani 1 1 d . . . . .
C11 C 0.7211(5) 0.1568(13) 0.4445(6) 0.0497(17) Uani 1 1 d . . . . .
H11 H 0.671184 0.012426 0.406293 0.060 Uiso 1 1 calc R U . . .
C16 C 0.9274(7) -0.0969(16) 0.5927(7) 0.062(2) Uani 1 1 d . . . . .
H16 H 0.960900 -0.227734 0.645725 0.074 Uiso 1 1 calc R U . . .
C4 C 0.2086(6) 0.4572(15) 0.4456(6) 0.0558(18) Uani 1 1 d . . . . .
H4 H 0.168520 0.599024 0.394800 0.067 Uiso 1 1 calc R U . . .
C5 C 0.3893(7) 0.4915(17) 0.6146(7) 0.067(2) Uani 1 1 d . . . . .
H5 H 0.472319 0.552290 0.652635 0.080 Uiso 1 1 calc R U . . .
C6 C 0.1997(6) 0.4763(16) 0.5728(6) 0.061(2) Uani 1 1 d . . . . .
H6 H 0.120382 0.526447 0.574356 0.073 Uiso 1 1 calc R U . . .
C12 C 0.7537(6) 0.1624(14) 0.5800(6) 0.0529(17) Uani 1 1 d . . . . .
H12 H 0.719487 0.023116 0.611436 0.063 Uiso 1 1 calc R U . . .
C3 C 0.3446(6) 0.4649(15) 0.4750(7) 0.0577(18) Uani 1 1 d . . . . .
H3 H 0.369587 0.606127 0.436435 0.069 Uiso 1 1 calc R U . . .
C8 C 0.2480(9) 0.2490(17) 0.6364(7) 0.071(2) Uani 1 1 d . . . . .
H8 H 0.204035 0.122342 0.656061 0.085 Uiso 1 1 calc R U . . .
loop_
_atom_type_symbol
_atom_type_description
_atom_type_scat_dispersion_real
_atom_type_scat_dispersion_imag
_atom_type_scat_source
C C 0.0181 0.0091 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4'
H H 0.0000 0.0000 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4'
O O 0.0492 0.0322 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4'
loop_
_geom_angle_atom_site_label_1
_geom_angle_atom_site_label_2
_geom_angle_atom_site_label_3
_geom_angle
_geom_angle_site_symmetry_1
_geom_angle_site_symmetry_3
_geom_angle_publ_flag
C10 O5 C9 110.6(6) . . ?
C13 O8 C14 96.1(5) . . ?
C1 O1 C2 110.8(6) . . ?
C5 O4 C6 94.6(6) . . ?
O5 C9 C11 110.2(6) . . ?
O6 C9 O5 119.5(7) . . ?
O6 C9 C11 130.3(7) . . ?
O3 C2 O1 119.6(8) . . ?
O3 C2 C4 130.3(7) . . ?
O1 C2 C4 110.1(6) . . ?
C13 C15 H15 127.0 . . ?
C16 C15 H15 127.0 . . ?
C16 C15 C13 106.1(7) . . ?
O8 C13 C15 102.8(6) . . ?
O8 C13 H13 115.1 . . ?
O8 C13 C11 100.5(5) . . ?
C15 C13 H13 115.1 . . ?
C15 C13 C11 106.4(6) . . ?
C11 C13 H13 115.1 . . ?
O5 C10 C12 111.3(6) . . ?
O7 C10 O5 119.7(8) . . ?
O7 C10 C12 129.0(7) . . ?
O8 C14 H14 115.8 . . ?
O8 C14 C16 101.7(6) . . ?
O8 C14 C12 100.1(5) . . ?
C16 C14 H14 115.8 . . ?
C16 C14 C12 105.4(6) . . ?
C12 C14 H14 115.8 . . ?
C5 C7 H7 126.8 . . ?
C8 C7 H7 126.8 . . ?
C8 C7 C5 106.5(8) . . ?
O1 C1 C3 110.5(6) . . ?
O2 C1 O1 119.5(8) . . ?
O2 C1 C3 130.0(7) . . ?
C9 C11 C13 110.8(6) . . ?
C9 C11 H11 113.2 . . ?
C9 C11 C12 104.4(6) . . ?
C13 C11 H11 113.2 . . ?
C12 C11 C13 101.3(5) . . ?
C12 C11 H11 113.2 . . ?
C15 C16 C14 105.4(7) . . ?
C15 C16 H16 127.3 . . ?
C14 C16 H16 127.3 . . ?
C2 C4 H4 111.4 . . ?
C2 C4 C6 115.6(7) . . ?
C2 C4 C3 105.0(6) . . ?
C6 C4 H4 111.4 . . ?
C3 C4 H4 111.4 . . ?
C3 C4 C6 101.6(5) . . ?
O4 C5 C7 102.1(7) . . ?
O4 C5 H5 115.6 . . ?
O4 C5 C3 99.6(6) . . ?
C7 C5 H5 115.6 . . ?
C7 C5 C3 106.4(7) . . ?
C3 C5 H5 115.6 . . ?
O4 C6 C4 98.9(6) . . ?
O4 C6 H6 115.3 . . ?
C4 C6 H6 115.3 . . ?
C8 C6 O4 102.5(6) . . ?
C8 C6 C4 107.8(7) . . ?
C8 C6 H6 115.3 . . ?
C10 C12 C14 109.7(6) . . ?
C10 C12 C11 103.5(6) . . ?
C10 C12 H12 113.7 . . ?
C14 C12 H12 113.7 . . ?
C11 C12 C14 101.3(5) . . ?
C11 C12 H12 113.7 . . ?
C1 C3 C4 103.4(6) . . ?
C1 C3 C5 114.8(7) . . ?
C1 C3 H3 112.4 . . ?
C4 C3 C5 100.6(6) . . ?
C4 C3 H3 112.4 . . ?
C5 C3 H3 112.4 . . ?
C7 C8 C6 107.4(9) . . ?
C7 C8 H8 126.3 . . ?
C6 C8 H8 126.3 . . ?
loop_
_geom_bond_atom_site_label_1
_geom_bond_atom_site_label_2
_geom_bond_distance
_geom_bond_site_symmetry_2
_geom_bond_publ_flag
O5 C9 1.386(9) . ?
O5 C10 1.366(9) . ?
O6 C9 1.193(9) . ?
O3 C2 1.200(9) . ?
O8 C13 1.438(9) . ?
O8 C14 1.447(9) . ?
O1 C2 1.378(9) . ?
O1 C1 1.370(9) . ?
O4 C5 1.455(10) . ?
O4 C6 1.458(10) . ?
O7 C10 1.198(9) . ?
O2 C1 1.195(9) . ?
C9 C11 1.515(10) . ?
C2 C4 1.472(12) . ?
C15 H15 0.9400 . ?
C15 C13 1.493(11) . ?
C15 C16 1.326(11) . ?
C13 H13 0.9900 . ?
C13 C11 1.562(9) . ?
C10 C12 1.517(11) . ?
C14 H14 0.9900 . ?
C14 C16 1.525(11) . ?
C14 C12 1.568(10) . ?
C7 H7 0.9400 . ?
C7 C5 1.483(14) . ?
C7 C8 1.285(13) . ?
C1 C3 1.492(12) . ?
C11 H11 0.9900 . ?
C11 C12 1.533(9) . ?
C16 H16 0.9400 . ?
C4 H4 0.9900 . ?
C4 C6 1.568(10) . ?
C4 C3 1.535(10) . ?
C5 H5 0.9900 . ?
C5 C3 1.574(11) . ?
C6 H6 0.9900 . ?
C6 C8 1.452(12) . ?
C12 H12 0.9900 . ?
C3 H3 0.9900 . ?
C8 H8 0.9400 . ?
loop_
_geom_torsion_atom_site_label_1
_geom_torsion_atom_site_label_2
_geom_torsion_atom_site_label_3
_geom_torsion_atom_site_label_4
_geom_torsion
_geom_torsion_site_symmetry_1
_geom_torsion_site_symmetry_2
_geom_torsion_site_symmetry_3
_geom_torsion_site_symmetry_4
_geom_torsion_publ_flag
O5 C9 C11 C13 -106.0(6) . . . . ?
O5 C9 C11 C12 2.2(7) . . . . ?
O5 C10 C12 C14 107.8(7) . . . . ?
O5 C10 C12 C11 0.4(8) . . . . ?
O6 C9 C11 C13 72.1(10) . . . . ?
O6 C9 C11 C12 -179.7(8) . . . . ?
O3 C2 C4 C6 71.5(11) . . . . ?
O3 C2 C4 C3 -177.5(8) . . . . ?
O8 C13 C11 C9 73.9(6) . . . . ?
O8 C13 C11 C12 -36.3(7) . . . . ?
O8 C14 C16 C15 -30.7(7) . . . . ?
O8 C14 C12 C10 -72.9(7) . . . . ?
O8 C14 C12 C11 36.0(7) . . . . ?
O1 C2 C4 C6 -106.7(7) . . . . ?
O1 C2 C4 C3 4.3(8) . . . . ?
O1 C1 C3 C4 0.4(8) . . . . ?
O1 C1 C3 C5 109.0(7) . . . . ?
O4 C5 C3 C1 -147.3(6) . . . . ?
O4 C5 C3 C4 -37.1(8) . . . . ?
O4 C6 C8 C7 -32.6(9) . . . . ?
O7 C10 C12 C14 -71.2(11) . . . . ?
O7 C10 C12 C11 -178.6(9) . . . . ?
O2 C1 C3 C4 -176.6(9) . . . . ?
O2 C1 C3 C5 -68.0(12) . . . . ?
C9 O5 C10 O7 -179.9(8) . . . . ?
C9 O5 C10 C12 1.1(8) . . . . ?
C9 C11 C12 C10 -1.5(7) . . . . ?
C9 C11 C12 C14 -115.1(6) . . . . ?
C2 O1 C1 O2 179.7(8) . . . . ?
C2 O1 C1 C3 2.4(8) . . . . ?
C2 C4 C6 O4 151.4(6) . . . . ?
C2 C4 C6 C8 45.2(9) . . . . ?
C2 C4 C3 C1 -2.8(8) . . . . ?
C2 C4 C3 C5 -121.6(7) . . . . ?
C15 C13 C11 C9 -179.3(6) . . . . ?
C15 C13 C11 C12 70.5(7) . . . . ?
C13 O8 C14 C16 48.4(6) . . . . ?
C13 O8 C14 C12 -59.9(6) . . . . ?
C13 C15 C16 C14 -0.8(7) . . . . ?
C13 C11 C12 C10 113.7(6) . . . . ?
C13 C11 C12 C14 0.0(7) . . . . ?
C10 O5 C9 O6 179.6(7) . . . . ?
C10 O5 C9 C11 -2.1(8) . . . . ?
C14 O8 C13 C15 -49.5(6) . . . . ?
C14 O8 C13 C11 60.1(6) . . . . ?
C7 C5 C3 C1 -41.7(8) . . . . ?
C7 C5 C3 C4 68.6(8) . . . . ?
C1 O1 C2 O3 177.3(7) . . . . ?
C1 O1 C2 C4 -4.3(8) . . . . ?
C16 C15 C13 O8 32.5(7) . . . . ?
C16 C15 C13 C11 -72.7(7) . . . . ?
C16 C14 C12 C10 -178.2(6) . . . . ?
C16 C14 C12 C11 -69.2(7) . . . . ?
C4 C6 C8 C7 71.1(9) . . . . ?
C5 O4 C6 C4 -62.5(7) . . . . ?
C5 O4 C6 C8 48.1(7) . . . . ?
C5 C7 C8 C6 1.3(10) . . . . ?
C6 O4 C5 C7 -46.9(7) . . . . ?
C6 O4 C5 C3 62.2(7) . . . . ?
C6 C4 C3 C1 118.0(7) . . . . ?
C6 C4 C3 C5 -0.9(8) . . . . ?
C12 C14 C16 C15 73.4(7) . . . . ?
C3 C4 C6 O4 38.4(7) . . . . ?
C3 C4 C6 C8 -67.8(8) . . . . ?
C8 C7 C5 O4 30.5(9) . . . . ?
C8 C7 C5 C3 -73.5(8) . . . . ?
