(IUCr) Crystallography Journals Online checkcif report

[Contents scheme]

Acta Cryst. (2002). E58, o1381-o1383 [ doi:10.1107/S1600536802020639 ]

Bis(pyridine)iodonium(I) tetrafluoroborate

C. Álvarez-Rúa, S. García-Granda, A. Ballesteros, F. González-Bobes and J. M. González

Online 22 November 2002

Key indicators

Single-crystal X-ray study
T = 120 K
Mean (C-C) = 0.007 Å
R factor = 0.036
wR factor = 0.141
Data-to-parameter ratio = 14.7

checkCIF results

No syntax errors found


 Alert Level B:



PLAT_112  Alert B ADDSYM Detects Additional (Pseudo) Symm. Elem.          S

Author response: The ADDSYM procedure detects this pseudo symmetry element when the distance criterion for coinciding atoms is not fulfilled. The default value for this parameter is 0.45 Angstrom. In this crystal structure, only four pairs of atoms (F11 - F24; C313 - C122; C124 - C314; F13 - F12) and the iodine atoms are related by a non-crystallographic translation of coordinates (0.511, 0.754, 0.008), which make them lie less than 0.45 Angstrom far apart. Noteworthy, only the iodine atoms are clearly close to each other after this translation (approximately 0.15 Angstrom), the rest of atoms being more than 0.43 Angstrom far apart. When the default value of the distance criterion is reset to 0.43 Angstrom, the automatic procedure ADDSYM does not detect this pseudo symmetry. Furthermore, the PLATON/CHECKCIF procedures ADDSYM EXACT and NEWSYM indicate that no obvious spacegroup change is needed. As indicated in the main text, the iodine atoms in the crystal structure seem to be defining a higher symmetry than the actual one which, on the other hand, is not supported by the remainder unit cell contents.


 Alert Level C:



ABSTM_02  Alert C The ratio of expected to reported Tmax/Tmin(RR) is > 1.10     
          Tmin and Tmax reported:      0.416     0.673                          
          Tmin and Tmax expected:      0.350     0.673                          
          RR =      1.189                                                       
          Please check that your absorption correction is appropriate.          


 0 Alert Level A = Potentially serious problem

 1 Alert Level B = Potential problem

 1 Alert Level C = Please check