essence of aromatic carbon?

An aromatic hydrocarbon or arena  
1 (sometimes also called aryl hydrocarbon) 
2 is a hydrocarbon with a single bond or a double bond, and between carbon atoms. Configuration 6 carbon atoms in an aromatic compound called benzene rings. Aromatic hydrocarbons can be monocyclic or polycyclic.
these compounds follow Hückel Rule. In these compounds, at least one carbon atom is replaced by another atom, such as oxygen, nitrogen, or sulfur. One contohn compound is furan, a heterocyclic ring compound having 5 members, one oxygen atom. Another example is pyridine, a heterocyclic ring compound with 6 members, one nitrogen atom.

 Simple aromatic rings, also known as a simple arena or simple aromatic compounds, is an aromatic organic compound that consists only of conjugate planar ring structure with a berdelokalisasi pi electron cloud. Many of simple aromatic ring compounds which have trivial names. Typically, it is found as a substructure of the molecules are more complex. Simple aromatic compounds are commonly found benzene and indole.
Aromatic rings can be a simple heterocyclic compound if it contains non-carbon atoms. It can be monocyclic such as benzene, naphthalene such bicyclic, or polycyclic like anthracene. Simple monocyclic aromatic ring is usually a five-membered ring, as pirola, or six-membered rings, such as pyridine

 Terms aromaticity
  Main article: Aromaticity
• Molecules must be a cyclic.
• Each atom in the ring must have pi orbital, forming a conjugate.
• The molecule must be planar.
• The number of pi electron molecule must be odd and satisfy Hückel rule: (4n +2) pi electrons.
The molecules containing 4n pi electrons are antiaromatik.
Hückel rule determines a planar ring molecules have aromatic properties. This rule was proposed by the German chemist Erich Hückel in 1931.
A planar ring molecules meet Hückel rule, if it has as many as π electron-4N +2, where n is an integer.
From the data aromatics hydrogenation of alkenes are more stable than expected, the stability of the "extra" is caused by a cloud of delocalized electrons, called resonance energy. Criteria for simple aromatic compounds:
1. Meet Hückel rule, have much 4N π electron cloud +2 in the delocalized p-orbital.
2. Shaped planar and cyclic.
3. Each atom in the ring must be able to participate in the delocalization of electrons by having a p-orbital or lone pair.