The conversion of a @R05025@ into a pure @E02069@ or into a mixture in which one @E02069@ is present in excess, or of a @D01679@ mixture into a single diastereoisomer or into a mixture in which one diastereoisomer predominates. This is sometimes called deracemization. If the two enantiomers of a @C01057@ substrate A are freely interconvertible and if an equal amount or excess of a non-racemizing second enantiomerically pure chemical species, say (R)-B, is added to a solution of @R05026@ A, then the resulting equilibrium mixture of adducts A · B will, in general, contain unequal amounts of the @D01679@ (R)-A · (R)-B and (S)-A · (R)-B. The result of this @E02175@ is called @A00478@ @T06446@ of the first kind. If, in such a system, the two diastereoisomeric adducts differ considerably in @S05740@ so that only one of them, say (R)-A · (R)-B, crystallizes from the solution, then the @E02175@ of @D01679@ in solution and concurrent @C01434@ will continue so that all (or most) of the substrate A can be isolated as the crystalline diastereoisomer (R)-A · (R)-B. Such a '@C01434@-induced @A00478@ @T06446@' is called an @A00478@ @T06446@ of the second kind.