Criteria for the Formation of Nonclassical Carbocations

According to Sargent, the following criteria indicate the intervention of a bridged 

1) enhanced rate of solvolysis relative to a similar model deprived of a-delo-calization capacity  

4) loss or retention of optical activity in cases when formation of the classical ion would lead to opposite results  

5) the phenomenon of ion-pair return to isomeric starting material. 

The well-known American chemist H. C. Brown has come out against the concept of nonclassical ions his main arguments will be discussed on the 

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