(IUCr) Crystallography Journals Online checkcif report

[Contents scheme]

Acta Cryst. (2002). E58, o27-o29 [ doi:10.1107/S1600536801020839 ]

N,N'-Dicyclohexyl-N-(2-pyrazinoyl)urea

F. Chérioux, B. Therrien, H. Stoeckli-Evans and G. Süss-Fink

Online 14 December 2001

Key indicators

Single-crystal X-ray study
T = 153 K
Mean (C-C) = 0.002 Å
R factor = 0.028
wR factor = 0.058
Data-to-parameter ratio = 10.8

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


 Alert Level C:



ABSMU_01  Alert C The ratio of given/expected absorption coefficient lies       
          outside the range 0.99 <> 1.01                                        
          Calculated value of mu =     0.082                                    
          Value of mu given      =     0.080                                    

STRVAL_01                                                                       
         From the CIF: _refine_ls_abs_structure_Flack    0.800                  
         From the CIF: _refine_ls_abs_structure_Flack_su    0.900               
           Alert C Chirality of atom sites is inverted?                         

General Notes



REFLT_03                                                                        
         From the CIF: _diffrn_reflns_theta_max           26.00                 
         From the CIF: _reflns_number_total               3477                  
         Count of symmetry unique reflns         2016                           
         Completeness (_total/calc)            172.47%                          
         TEST3: Check Friedels for noncentro structure                          
         Estimate of Friedel pairs measured      1461                           
         Fraction of Friedel pairs measured     0.725                           
         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

 2 Alert Level C = Please check