(IUCr) Crystallography Journals Online checkcif report

[Contents scheme]

Acta Cryst. (2003). E59, o553-o554 [ doi:10.1107/S1600536803005609 ]

Methyl (E)-2-acetyl-3-amino-2-pentenoate

X. Chen and T. Chen

Online 31 March 2003

Key indicators

Single-crystal X-ray study
T = 294 K
Mean (C-C) = 0.004 Å
R factor = 0.048
wR factor = 0.087
Data-to-parameter ratio = 18.0

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


 Alert Level C:



STRVAL_01                                                                       
         From the CIF: _refine_ls_abs_structure_Flack   -0.500                  
         From the CIF: _refine_ls_abs_structure_Flack_su    1.600               
           Alert C Flack parameter is too small                                 

General Notes



REFLT_03                                                                        
         From the CIF: _diffrn_reflns_theta_max           27.55                 
         From the CIF: _reflns_number_total               2037                  
         Count of symmetry unique reflns         1134                           
         Completeness (_total/calc)            179.63%                          
         TEST3: Check Friedels for noncentro structure                          
         Estimate of Friedel pairs measured       903                           
         Fraction of Friedel pairs measured     0.796                           
         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.     


 0 Alert Level A = Potentially serious problem

 0 Alert Level B = Potential problem

 1 Alert Level C = Please check