Nowadays, simulation methods changed chemistry from being a purely empirical science to be semi empirical science. Azides compounds are characterized as highly unstable compounds with an explosive nature so for sure exploring their physical properties through an experimental work is a risky job and now we can appreciate the importance of computational chemistry as a vital tool in helping chemists to reach to their destinations with minimum losses (time, chemicals and personal safety). This book therefore, represents a typical systematic approach to any new comer to the field of computational chemistry. This book starts with a very simplified approach for explaining the fundamental concepts of Quantum Chemistry, followed by studying the azides compounds; halocarbonylazides, halovinylazides, dihalovinylazides, nitrosoazide, nitroazide and halosulfonylazidies. The ab initio calculations by the extended basis set 6-311++G** extended basis set at the DFT-B3LPY was utilized into this study.