University:
Purdue University
Course:
CHM 62100 | Advanced Analytical Chemistry
Academic year:

2019
Views:

127

Pages:

10
Author:

ilikemyicons0y5

p-p overlapping • In this condition, one half-filled p orbital from each participating atom undergoes head-on overlapping along the internuclear axis. This type of overlapping is illustrated below. P to P overlap • A Cl2 molecule features a p-p overlap of the 3pz orbitals of two chlorine atoms. It is important to note that the head-to-head overlapping of two p orbitals gives a sigma bond whereas the lateral overlap of these orbitals leads to the formation of pi bonds. The Pi (π) Bond • Pi bonds are formed by the lateral (sidewise / positive (same phase) overlap of atomic orbitals along a direction perpendicular to the internuclear axis. During the formation of π bonds, the axes of the atomic orbitals are parallel to each other whereas the overlapping is perpendicular to the internuclear axis. This type of covalent bonding is illustrated below. Weakness of pi bonds • Pi Bonds are generally weaker than sigma bonds, owing to the significantly lower degree of overlapping. • Generally, double bonds consist of one sigma and one pi bond, whereas • a typical triple bond is made up of two π bonds and one σ bond. • It is important to note that a combination of sigma and pi bonds is always stronger than a single sigma bond. Amount of sigma and Pi Bonds that exists exists in Double and Triple Bonds? • A triple bond consists of two pi bonds and one sigma bond. • A double bond contains one sigma and one pi bond. • Single bonds are always sigma bonds. Free rotation • Sigma bonds are defined as having their electron density along the bond axis, while pi bonds have their electron density above and below the bond axis. What this mean is that pi bonds cannot rotate the same way as sigma bonds since rotation would break the pi bond interaction. Question would there be rotation across a single, double and triple bond?