(IUCr) Crystallography Journals Online checkcif report

[Contents scheme]

Acta Cryst. (2003). E59, o771-o772 [ doi:10.1107/S1600536803009590 ]

Trilobolide-6-O-isobutyrate, a eudesmanolide from Wedelia trilobata

X.-S. Huang, R.-W. Jiang and V.E.-C. Ooi

Online 9 May 2003

Key indicators

Single-crystal X-ray study
T = 293 K
Mean (C-C) = 0.009 Å
R factor = 0.051
wR factor = 0.153
Data-to-parameter ratio = 7.6

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


 Alert Level A:



TYPE_089  Alert A _refine_ls_abs_structure_Flack is not of type numb.           

REFI_021  Alert A _refine_ls_abs_structure_details is missing                   
          Absolute structure method and Friedel-pair number.                    
          This should be present as the _refine_ls_abs_structure_Flack or Roger 
          field has been filled out.                                            


 Alert Level C:



REFNR_01  Alert C Ratio of reflections to parameters is < 8 for a               
          non-centrosymmetric structure, where ZMAX < 18                        
          sine(theta)/lambda                0.5946                              
          Proportion of unique data used    0.5079                              
          Ratio reflections to parameters   7.5679                              

PLAT_737  Alert C D...A   Calc    2.985(7), Rep    2.986(3) ....       2.33 su-Ratio
                     O5   -O9      1.555   1.545

General Notes



REFLT_03                                                                        
         From the CIF: _diffrn_reflns_theta_max           25.00                 
         From the CIF: _reflns_number_total               4172                  
         Count of symmetry unique reflns         2123                           
         Completeness (_total/calc)            196.51%                          
         TEST3: Check Friedels for noncentro structure                          
         Estimate of Friedel pairs measured      2049                           
         Fraction of Friedel pairs measured     0.965                           
         Are heavy atom types Z>Si present           no                         
          ALERT: MoKa measured Friedel data cannot be used to                   
                 determine absolute structure in a light-atom                   
                 study EXCEPT under VERY special conditions.                    
                 It is preferred that Friedel data is merged in such cases.     


 2 Alert Level A = Potentially serious problem

 0 Alert Level B = Potential problem

 2 Alert Level C = Please check