How To Use -

This is a simple tool to calculate the number of rings and/or pi bonds in an organic molecule. First count how many carbon atoms there are in the given molecule and enter it into the text-box accordingly. Do the same for Hydrogen atoms, Nitrogen atoms, and Halogen atoms(F, Cl, Br, I, At). The value that is returned should be a whole positive number representative of, again, the number of rings and/or pi bonds.

Degrees of Unsaturation Calculator -

TI83 - Source Code -

:ClrHome
:Disp "DEGREES OF"
:Disp " UNSATURATION"
:Prompt C,H,N,X
:((2*C + 2 + N - X - H)/2)->D
:Disp "Pi/Rings: ", D
:Delvar D
:Delvar C
:Delvar H
:Delvar N
:Delvar X

Additional -

This simple calculation is used many times in Organic Chemistry. It's useful in HNMR/IR characterization of molecules and many other processes. Or any problem where you need to draw isomers from an empirical formula. I use it so much I even programmed it into my calculator. The code is provided above. Feel free to rip the javascript from this page. Please give credit if you do rip it. Not that this is challenging mathematically by any means, but us scientists in general are lazy people.