Dimethyl 2,2,6,6-Tetramethyl-3,5-dioxo-4-oxaheptanedioate
Graham, J. E.; Bunce, R. A.; Holt, E. M.; Acta Crystallographica Section C 52 (1996) 436–438; doi:10.1107/S0108270195012066

data_2004489
_publ_section_title
;
 Dimethyl 2,2,6,6-Tetramethyl-3,5-dioxo-4-oxaheptanedioate
;
_journal_issue                   2
_journal_name_full               'Acta Crystallographica Section C'
_journal_page_first              436
_journal_page_last               438
_journal_paper_doi               10.1107/S0108270195012066
_journal_volume                  52
_journal_year                    1996
_chemical_formula_moiety         'C12 H18 O7'
_chemical_formula_sum            'C12 H18 O7'
_chemical_formula_weight         274.3
_chemical_melting_point          .65E-64
_chemical_name_systematic
;
dimethyl 2,2,6,6-tetramethyl-4-oxa-3,5-dioxoheptanedioate
;
_space_group_IT_number           2
_symmetry_cell_setting           triclinic
_symmetry_space_group_name_Hall  '-P 1'
_symmetry_space_group_name_H-M   'P -1'
_cell_angle_alpha                72.38(2)
_cell_angle_beta                 73.20(2)
_cell_angle_gamma                88.54(2)
_cell_formula_units_Z            2
_cell_length_a                   8.052(2)
_cell_length_b                   9.627(3)
_cell_length_c                   10.017(3)
_cell_measurement_reflns_used    53
_cell_measurement_temperature    301
_cell_measurement_theta_max      20.0
_cell_measurement_theta_min      3.5
_cell_volume                     706.8(4)
_computing_cell_refinement       XSCANS
_computing_data_collection       'XSCANS (Siemens, 1991)'
_computing_molecular_graphics    'XP (Siemens, 1990)'
_computing_publication_material  XP
_computing_structure_refinement  SHELXS86
_computing_structure_solution    'SHELXS86 (Sheldrick, 1990)'
_diffrn_ambient_temperature      301
_diffrn_measurement_device       'Siemens P4 four-circle'
_diffrn_measurement_method       \q/2\q
_diffrn_radiation_monochromator  'highly oriented graphite crystal'
_diffrn_radiation_source         'X-ray sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0477
_diffrn_reflns_limit_h_max       7
_diffrn_reflns_limit_h_min       -7
_diffrn_reflns_limit_k_max       8
_diffrn_reflns_limit_k_min       -8
_diffrn_reflns_limit_l_max       9
_diffrn_reflns_limit_l_min       0
_diffrn_reflns_number            1667
_diffrn_reflns_theta_max         20
_diffrn_reflns_theta_min         1.75
_diffrn_standards_decay_%        7.71
_diffrn_standards_interval_count 97
_diffrn_standards_number         3
_exptl_absorpt_coefficient_mu    0.107
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.289
_exptl_crystal_density_meas      ?
_exptl_crystal_description       rhombic
_exptl_crystal_F_000             292
_exptl_crystal_size_max          0.25
_exptl_crystal_size_mid          0.25
_exptl_crystal_size_min          0.25
_refine_diff_density_max         0.21
_refine_diff_density_min         -0.15
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_obs   1.15
_refine_ls_matrix_type           full
_refine_ls_number_parameters     173
_refine_ls_number_reflns         1298
_refine_ls_R_factor_all          .0579
_refine_ls_R_factor_obs          .0406
_refine_ls_shift/esd_max         0.001
_refine_ls_shift/esd_mean        0.000
_refine_ls_structure_factor_coef F
_refine_ls_weighting_details     'w = 1/[\s^2^(F) + 0.008F^2^]'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_all         .0602
_refine_ls_wR_factor_obs         .0516
_reflns_number_observed          962
_reflns_number_total             1292
_reflns_observed_criterion       F>4.0\s(F)
_cod_data_source_file            cr1201.cif
_cod_data_source_block           1
_cod_depositor_comments
;
The following automatic conversions were performed:

'_exptl_crystal_density_meas' value 'not measured' was changed to '?'
- the value is perceived as not measured.

Automatic conversion script
Id: cif_fix_values 3008 2015-01-20 13:52:24Z robertas 

The following automatic conversions were performed:

'_refine_ls_weighting_scheme' value 'w = 1/[\s^2^(F) + 0.008F^2^]'
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^(F) +
0.008F^2^]'.

Automatic conversion script
Id: cif_fix_values 3143 2015-03-26 13:38:13Z robertas 
;
_cod_original_cell_volume        706.9(4)
_cod_database_code               2004489