Bond, chemical types sigma

Beyond predicting what types of bonds are present in a molecule, however, the Lewis structure tells us fairly little about the details of a chemical bond. To understand just how electrons are shared, we must reahze that electrons behave as waves and that when waves overlap, they interfere with each other. When the waves buildup they are said to interfere constructively and the chemical implication is the formation of a chemical bond. Overlap can be achieved in more than one way, so that we can distinguish types of bonds as either sigma or pi bonds. 

Sigma Bond—a type of covalent chemical bond that is formed from the sharing of electrons in s or s-hybrid orbitals. 

Supramolecular chemistry has been defined by the winner of Nobel Prize in Chemistry J.M. Lehn as Intermolecular chemistry, focusing on the structure and function of the entities formed by the association of two or more chemical species [7]. Supramolecular chemistry has provoked a substantial shift in chemistry from its interest in the molecule (atoms and bonds that form them) to focus on the association between the molecule and bonds between molecules. This concepmal change impacted all areas of chemistry. The intermolecular term is a synonym of non-covalent, which is explained by interactions of the type electrostatic, hydrogen bonding, and van der Waals [8, 9]. The expression non-covalent implies that the association type between two or more molecules is not explained by the traditional chemical bond concept, e.g., sigma bond with two electrons. 

Covalent bonds are characterized by shared electrons between atoms. Sigma bonds are the strongest type of covalent bonds and are formed by overlapping between atomic orbitals. Pi bonds are weaker covalent chemical bonds where two lobes of an atomic orbital overlap two lobes of another atomic orbital. 

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