Index of Hydrogen Deficiency (IHD) Calculator

Formula

The formula to calculate the Index of Hydrogen Deficiency (IHD) is:

\[ \text{IHD} = \frac{2C + 2 + N - X - H}{2} \]

Where:

\( \text{IHD} \) is the Index of Hydrogen Deficiency
\( C \) is the Number of Carbon Atoms
\( N \) is the Number of Nitrogen Atoms
\( X \) is the Number of Halogen Atoms
\( H \) is the Number of Hydrogen Atoms

What is an Index of Hydrogen Deficiency?

The Index of Hydrogen Deficiency (IHD) is a count of how many molecules of hydrogen a compound is missing compared to the maximum possible number of hydrogen atoms it could contain. It is used in organic chemistry to help identify and classify organic compounds. The IHD can indicate the presence of unsaturated bonds (double or triple bonds) or rings in the molecule, as these features reduce the number of hydrogen atoms a compound can hold.

Example Calculation

Let's consider an example:

Number of Carbon Atoms (C): 6
Number of Nitrogen Atoms (N): 1
Number of Halogen Atoms (X): 0
Number of Hydrogen Atoms (H): 12

Using the formula to calculate the Index of Hydrogen Deficiency:

\[ \text{IHD} = \frac{2 \times 6 + 2 + 1 - 0 - 12}{2} = \frac{13}{2} = 1.5 \]

This demonstrates that with the given number of carbon, nitrogen, halogen, and hydrogen atoms, the IHD would be 1.5, indicating the presence of unsaturation in the molecule.