A simple generic structural formula

We present a simple example of a generic structural formula and construct the search space that is obtained by combining the molecular formula and reaction-based struc- 

Variation of substituents There are different possibilities for substituent R. Variation of homology For R we can choose any element of a specified homologous series. Alkyl groups are all structures with a molecular formula of the form n 2n+l U IN.  

Variation of position Substituent R can be in one of several positions. In the structural formula above this is illustrated with a bond of R placed between two connected C atoms. The position that is not taken by the substituent is occupied by a H atom. 

Variation of chain length Up to three chain links of the form CH2 may be added to 

In reality, generic structural formulas are often much more complicated. In particular the complexity can increase considerably by combination and recursion of the principles described above. For example, variation of substituents and positions can occur, while the various substituents R can themselves be described by generic structural formulas. Variations resulting from homology especially can result in the possibility of an infinite structure space. In our example, we assume that only alkyl groups with 1 - 6 C atoms are allowed. Such restrictions are certainly both reasonable and necessary. 

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