A Some Introductory Data

It is reasonable to discuss firstly the main results obtained by the vibrational spectroscopy in studying some other types of carbenium ions . 

Olah and co-workers 39,44 ) recorded the IR and Raman spectra of alkyl- 

Comparison of the IR and Raman spectra of the trimethylcarbenium ion with those of its isoelectric analogue — trimethylboron — has conflrmed the planar structure of alkylcarbenium ions. The planar structure of the carbenium fragment —C was also concluded from the IR spectra of salts of the triphenylmethyl cation (CgH5)3C 449-451) analogues having different substituents at the para positions of the 

Information has been obtained on the C—C stretching vibrations of various enyl carbenium ions. The IR spectrum of [CClj CCl CCl2] shows this penta-chloroallyl cation to have a planar structure, the antisymmetric stretching vibration of its C—C bonds displaying itself at 1350 cm and the symmetric, at 1040 cm  

To judge by the frequencies of this cation, the C—C bond order is close to the expected value 1.5. The stretching vibrations of the bonds between the sp -hybridized carbon atoms of 4-X-l,2,3,4-tetramethylcyclobutenyl cations (59) are responsible for the very strong bands in the range of 1465-1475 cm (for polymethyl- 

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