The history of carbocations dates back to 1891 when G. Merling reported that he added bromine to tropylidene ( cycloheptatriene ) and then heated the product to obtain a crystalline , water-soluble material , C 7H 7Br .
In 1891 , G. Merling reported that he added bromine to tropylidene ( cycloheptatriene ) and then heated the product to obtain a crystalline , water soluble material , C7H7Br .