Book Cover Organic Chemistry 4e Carey
Online Learning Center

Chapter 13: Spectroscopy



Infra Red | Nuclear Magnetic Resonance | Ultra-violet/visible | Mass Spectrometry | Getting Structures from Spectra | Index of Hydrogen Deficiency |


Index of Hydrogen Deficiency (IHD)

Chapter 13: Spectroscopy

The Index of Hydrogen Deficiency (IHD), is a count of how many molecules of H2 need to be added to a structure in order to obtain the corresponding saturated, acyclic species.
Hence it takes a count of how many rings and multiple bonds are present in the structure, so IHD can also be thought of as (multiple bonds + rings) or (p + r).

When you look at a structure, just count them up (but take care not to count any rings twice !)
If you have a molecular formula, CcHhNnOoXx, then the following equation can be derived:

IHD = 0.5 * [2c+2-h-x+n]

Where does this equation come from?

Determining the IHD for molecules can be useful for the following reasons: What is the IHD of the following molecular formula?
 
C6H10
C6H6
C4H8O
C4H9N
C2Cl2
IHD = 2
IHD = 4
IHD = 1
IHD = 1
IHD = 2


HOME UP PREVIOUS

Begin a search: Catalog | Site | Campus Rep

MHHE Home | About MHHE | Help Desk | Legal Policies and Info | Order Info | What's New | Get Involved


Copyright ©2000 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use and Privacy Policy.
McGraw-Hill Higher Education is one of the many fine businesses of The McGraw-Hill Companies.
For further information about this site contact mhhe_webmaster@mcgraw-hill.com.


Corporate Link