Many aromatic compounds have an odor, but some compounds are aromatic but do not have a distinct odor. A compound can be classified as an aromatic compound if it has the properties mentioned previously and if it follows Huckel's rule, which we will discuss in the next section. !!!Huckel's rule: definition and examplesFor a compound to be aromatic, it must also satisfy Huckel's rule. __Huckel's Rule__ states that an aromatic compound must have a certain number of pi electrons. The number of pi electrons must be equal to 4n+2, where n is equal to zero or any positive integer (n = 0, 1, 2…). What is a pi electron? A __pi__ electron are the electrons present in double bonds. To check if a compound follows Huckel's rule, we first need to count the number of pi electrons – these are the electrons in the double bonds in the ring. In our example below, benzene, there are six pi electrons. Count the Pi electrons in