data_2003519 _journal_name_full 'Acta Crystallographica' _journal_year 1995 _journal_volume C51 _journal_page_first 1137 _journal_page_last 1139 _publ_section_title ; cis- and trans-Spiro[(4',4'-dimethyl-2',6'-dioxacyclohexane)-1',3- (4-methylenebicyclo[3.3.0]octane)]-2,2-dicarboxylate ; _chemical_formula_moiety 'C18 H26 O6' _chemical_formula_sum 'C18 H26 O6' _chemical_formula_structural 'C18 H26 O6' _chemical_formula_weight 338.39 loop_ _symmetry_equiv_pos_as_xyz 'x, y, z' '-x, -y, -z' _symmetry_space_group_name_H-M 'P -1' _cell_length_a 9.4915(11) _cell_length_b 11.5618(14) _cell_length_c 8.9687(9) _cell_angle_alpha 98.806(9) _cell_angle_beta 99.065(9) _cell_angle_gamma 112.364(9) _cell_volume 874.0(2) _cell_formula_units_Z 2 _exptl_crystal_density_diffrn 1.286 _exptl_crystal_density_meas ? _exptl_crystal_density_method ? _diffrn_radiation_type MoK\a _diffrn_radiation_wavelength 0.71073 _cell_measurement_reflns_used 25 _cell_measurement_theta_min 29.38 _cell_measurement_theta_max 29.97 _exptl_absorpt_coefficient_mu 0.096 _cell_measurement_temperature 296(2) _exptl_crystal_description 'prismatic' _exptl_crystal_size_max 0.60 _exptl_crystal_size_mid 0.30 _exptl_crystal_size_min 0.20 _exptl_crystal_colour 'colourless' _chemical_compound_source ? _diffrn_measurement_device 'AFC7R' _diffrn_measurement_method \w/2\q _exptl_absorpt_correction_type '\y scan' _exptl_absorpt_correction_T_min 0.972 _exptl_absorpt_correction_T_max 1.000 _diffrn_reflns_number 4033 _reflns_number_total 4033 _reflns_number_observed 2259 _reflns_observed_criterion >2sigma(I) _diffrn_reflns_av_R_equivalents 0.021 _diffrn_reflns_theta_max 27.49 _diffrn_reflns_limit_h_min 0 _diffrn_reflns_limit_h_max 12 _diffrn_reflns_limit_k_min -15 _diffrn_reflns_limit_k_max 13 _diffrn_reflns_limit_l_min -11 _diffrn_reflns_limit_l_max 11 _diffrn_standards_number 3 _diffrn_standards_interval_count 100 _diffrn_standards_interval_time ? _diffrn_standards_decay_% -0.41 _refine_ls_structure_factor_coef Fsqd _refine_ls_R_factor_obs 0.054 _refine_ls_wR_factor_obs 0.129 _refine_ls_wR_factor_all 0.159 _refine_ls_goodness_of_fit_obs 1.129 _refine_ls_goodness_of_fit_all 1.010 _refine_ls_number_reflns 4033 _refine_ls_number_parameters 295 _refine_ls_hydrogen_treatment refxyz _refine_ls_weighting_scheme 'calc w=1/[\s^2^(Fo^2^)+(0.0674P)^2^+0.1697P] wh _refine_ls_shift/esd_max 0.007 _refine_diff_density_max 0.17 _refine_diff_density_min -0.28 _refine_ls_extinction_method none _refine_ls_extinction_coef ? loop_ _atom_type_symbol _atom_type_description _atom_type_scat_source _atom_type_scat_dispersion_real _atom_type_scat_dispersion_imag 'C' 'C' 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4' 0.0033 0.001 'H' 'H' 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4' 0.0000 0.000 'O' 'O' 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4' 0.0106 0.006 ;MSC/AFC Diffractometer Control Software (Molecular Structure Corporation, 1992) ; loop_ _atom_site_label _atom_site_occupancy _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_U_iso_or_equiv O1 1 0.6834(2) 0.4923(2) 0.1059(2) 0.062 O2 1 0.5330(2) 0.4158(2) 0.2667(2) 0.053 O3 1 0.7428(2) 0.2375(2) -0.0715(2) 0.078 O4 1 0.9126(2) 0.3764(2) 0.1420(2) 0.050 O5 1 0.7414(2) 0.1542(2) 0.2715(2) 0.045 O6 1 0.7938(2) 0.3576(1) 0.4205(2) 0.044 C1 1 0.6454(3) 0.2841(2) 0.1524(3) 0.041 C2 1 0.6829(3) 0.2487(2) 0.3106(3) 0.040 C3 1 0.5219(3) 0.1830(2) 0.3443(3) 0.044 C4 1 0.4095(3) 0.1082(2) 0.1906(3) 0.048 C5 1 0.2482(4) 0.1124(4) 0.1586(4) 0.066 C6 1 0.2078(4) 0.1000(3) -0.0153(4) 0.065 C7 1 0.3617(3) 0.1890(3) -0.0449(3) 0.058 C8 1 0.4874(3) 0.1672(2) 0.0640(3) 0.046 C9 1 0.4860(4) 0.1915(3) 0.4811(4) 0.059 C10 1 0.6259(3) 0.4103(2) 0.1728(3) 0.042 C11 1 0.4975(4) 0.5269(3) 0.2844(4) 0.063 C12 1 0.7700(3) 0.2950(2) 0.0597(3) 0.046 C13 1 1.0408(4) 0.3854(4) 0.0688(4) 0.068 C14 1 0.8017(4) 0.1189(3) 0.4058(3) 0.054 C15 1 0.9370(3) 0.2341(3) 0.5164(3) 0.051 C16 1 0.8750(4) 0.3354(3) 0.5567(3) 0.050 C17 1 0.9890(5) 0.1969(4) 0.6646(4) 0.072 C18 1 1.0754(4) 0.2863(4) 0.4418(4) 0.069 H1 1 0.5195(37) 0.1034(32) 0.0045(37) 0.085 H2 1 0.3616(37) 0.1627(31) -0.1574(40) 0.085 H3 1 0.3769(37) 0.2801(34) -0.0173(36) 0.085 H4 1 0.1740(38) 0.0096(34) -0.0736(37) 0.085 H5 1 0.1161(39) 0.1238(31) -0.0495(36) 0.085 H6 1 0.1822(42) 0.0462(34) 0.1890(37) 0.085 H7 1 0.2585(38) 0.1990(33) 0.2166(37) 0.085 H8 1 0.3938(36) 0.0149(32) 0.1736(36) 0.085 H9 1 0.3764(40) 0.1422(31) 0.4877(36) 0.085 H10 1 0.5608(39) 0.2475(32) 0.5784(38) 0.085 H11 1 0.4252(39) 0.5181(31) 0.3518(39) 0.085 H12 1 0.4559(39) 0.5379(32) 0.1903(41) 0.085 H13 1 0.5961(39) 0.6045(34) 0.3259(37) 0.085 H14 1 1.0118(37) 0.3898(31) -0.0412(40) 0.085 H15 1 1.0488(39) 0.3071(34) 0.0513(38) 0.085 H16 1 1.1346(40) 0.4672(33) 0.1420(37) 0.085 H17 1 0.7142(39) 0.0786(30) 0.4638(37) 0.085 H18 1 0.8324(37) 0.0495(32) 0.3635(36) 0.085 H19 1 0.8030(39) 0.3117(30) 0.6259(38) 0.085 H20 1 0.9585(39) 0.4221(33) 0.6077(36) 0.085 H21 1 1.0450(38) 0.3081(31) 0.3477(40) 0.085 H22 1 1.1158(39) 0.2230(33) 0.4239(38) 0.085 H23 1 1.1627(40) 0.3709(33) 0.5132(38) 0.085 H24 1 1.0781(40) 0.2730(34) 0.7366(38) 0.085 H25 1 0.9027(39) 0.1650(31) 0.7150(38) 0.085 H26 1 1.0199(38) 0.1274(33) 0.6404(38) 0.085 loop_ _atom_site_aniso_label _atom_site_aniso_U_11 _atom_site_aniso_U_12 _atom_site_aniso_U_13 _atom_site_aniso_U_22 _atom_site_aniso_U_23 _atom_site_aniso_U_33 O1 0.0702(13) 0.0281(10) 0.0364(11) 0.0519(11) 0.0379(10) 0.0818(13) O2 0.0719(12) 0.0358(9) 0.0298(9) 0.0492(10) 0.0177(8) 0.0551(10) O3 0.0752(14) 0.0070(11) 0.0309(10) 0.0809(14) -0.0086(10) 0.0513(11) O4 0.0498(11) 0.0170(9) 0.0222(8) 0.0551(10) 0.0126(8) 0.0458(9) O5 0.0614(11) 0.0264(8) 0.0181(8) 0.0394(9) 0.0067(7) 0.0410(9) O6 0.0558(10) 0.0164(8) 0.0126(7) 0.0333(8) 0.0054(6) 0.0387(8) C1 0.0484(14) 0.0135(10) 0.0192(10) 0.0342(11) 0.0094(9) 0.0398(12) C2 0.0526(14) 0.0184(10) 0.0196(11) 0.0328(11) 0.0072(9) 0.0389(12) C3 0.0552(15) 0.0174(11) 0.0235(12) 0.0307(11) 0.0128(10) 0.0496(13) C4 0.052(2) 0.0120(11) 0.0205(12) 0.0367(12) 0.0094(11) 0.0510(14) C5 0.049(2) 0.016(2) 0.0231(15) 0.071(2) 0.016(2) 0.071(2) C6 0.056(2) 0.0145(15) 0.0097(15) 0.061(2) 0.0040(15) 0.065(2) C7 0.058(2) 0.0125(14) 0.0066(13) 0.051(2) 0.0080(13) 0.052(2) C8 0.0514(15) 0.0127(11) 0.0160(11) 0.0371(12) 0.0053(10) 0.0450(13) C9 0.065(2) 0.0212(15) 0.0333(15) 0.057(2) 0.0173(13) 0.058(2) C10 0.0455(14) 0.0144(11) 0.0100(11) 0.0370(12) 0.0106(10) 0.0401(12) C11 0.076(2) 0.044(2) 0.019(2) 0.060(2) 0.015(2) 0.069(2) C12 0.056(2) 0.0147(12) 0.0196(12) 0.0407(13) 0.0100(10) 0.0407(13) C13 0.065(2) 0.033(2) 0.041(2) 0.081(2) 0.025(2) 0.072(2) C14 0.081(2) 0.0376(15) 0.0208(14) 0.0470(15) 0.0155(12) 0.0480(15) C15 0.068(2) 0.0335(14) 0.0170(12) 0.0555(15) 0.0135(11) 0.0403(13) C16 0.064(2) 0.0226(13) 0.0134(12) 0.0469(14) 0.0072(11) 0.0376(13) C17 0.100(3) 0.051(2) 0.017(2) 0.078(2) 0.021(2) 0.052(2) C18 0.069(2) 0.043(2) 0.019(2) 0.093(3) 0.020(2) 0.056(2)