Degree of Unsaturation / Double Bond Equivalent (DBE)

$$\text{DBE} = C + 1 - \frac{H}{2} + \frac{N}{2} - \frac{X}{2}$$

Concept: Determines the total number of rings and/or $$\pi$$ -bonds present in an organic compound based on its molecular formula.

Notation & Interpretation:

• $$C$$ = Number of carbon atoms
• $$H$$ = Number of hydrogen atoms
• $$N$$ = Number of nitrogen atoms
• $$X$$ = Number of halogen atoms ($$\text{F, Cl, Br, I}$$)
• $$\text{DBE} = 1 \implies 1 \text{ Ring or } 1 \, \pi\text{-bond}$$
• $$\text{DBE} = 4 \implies \text{Benzene ring } (1 \text{ Ring } + 3 \, \pi\text{-bonds})$$