Introduction

Abstract

Every chemist concerned with the study of carbon compounds is confronted at intervals with the problem of identifying the substances with which he is working. These may be the reactants, the products, or the by-products. In some cases the problem is one of recognition, that is, the identification of substances previously isolated or prepared and described in the literature. At other times the problem is one of cognition or the determination of the constitution and structure of entirely new, hitherto unknown compounds. Since only rarely is sufficient information available to justify the assumption that the substance under investigation belongs to the first group, the approach must be broad enough to permit identification of compounds in either group. In either problem the chemist should be prepared to use any and all techniques available.