JCE Online Journal of Chemical Education
 | Subscriptions  | Software Orders  | Support  | Contributors  | Advertisers  | 

JCE Print
   Current Issue
 Previous Issues
 Supplements
 Search JCE Index

JCE Digital Library
   DigiDemos
 QBank
 SymMath
 WebWare

JCE Software
   Latest Releases
 Software & Video
 Downloads
 Support

Only@JCE Online
   JCE Online Store
 JCE HS CLIC
 JCE Discussion Forums
   Biographical Snapshots
 ChemEd Resource Shelf
 Featured Molecules
 Hal's Picks
 Project Chemlab
 Reviewed WWW Sites
 "Web-Ed" Articles

About JCE
   Features
 Publications
 Operations
 Outreach
 Contact Us


  Home > JCE Print > Journal of Chemical Education > Issues > 1999  > September  >
In the Laboratory
Geometry of Benzene from the Infrared Spectrum
Elisabetta Cané, Andrea Miani, and Agostino Trombetti
Università di Bologna, Dipartimento di Chimica Fisica e Inorganicia, Viale Risorgimento 4, 40136 Bologna, Italy
Cover
September 1999
Vol. 76 No. 9
p. 1288
Abstract
The structure of benzene is fully determined once the interatomic distances rcc and rCH are obtained from experimental data. This infrared spectroscopy experiment allows the determination of rcc and rCH from the rotational analysis of an infrared active band of C6H6 and one of its isotopomers, C6D6. Here the P and R branches of the n4 parallel band of C6H6 (674 cm-1) and of C6D6 (496 cm-1) are analyzed to determine the rotational constants B0 of the ground state of both isotopomers. From B0 values the moments of inertia are calculated and the rCC and rCH distances are obtained. The requirements of the experiment are availability of an IR spectrometer equipped with a KBr beam-splitter working at 0.2 cm-1 of resolution and a short cylindrical cell fitted with KBr windows. High-performance infrared detectors are not required because the bands recorded are the strongest in the spectrum. To fit the experimental wavenumbers of the R and P branch lines at least a second degree polynomial is needed. Such a mathematical tool is generally available on a PC. The values obtained agree fairly well with the literature data for the rotational analysis of high-resolution spectra. The aim of the experiment can be extended to allow the calculation of centrifugal distortion constants, transition moments, and anharmonic constants.
More Information
*  Citation
 CanŽ, Elisabetta; Miani, Andrea; Trombetti, Agostino. J. Chem. Educ. 1999 76 1288.
*  Keywords
 Physical Chemistry; IR Spectroscopy; Molecular Properties / Structure; benzene; Laboratory Instruction
*  History
 Created:
Last Updated:		 July 30, 1999
June 23, 2005
<< Previous Article Table of Contents Next Article >>
  Home > JCE Print > Journal of Chemical Education > Issues > 1999 > September > Page 1288


Subscriptions
 Subscription Info
 Order Forms

JCE HS CLIC

Our Secondary School editors work hard to distill all the JCE materials to produce a fraction of particular interest to high school teachers. We call it CLIC.
 JCE HS CLIC

Contributions Welcome
JCE welcomes your submission
 Contributors' Corner

Advertisers
In recent years we have worked hard to better match our advertisers with our readers. When shopping for chemistry education materials, visit our advertisers' WWW sites first.
 Recent Advertisers

Be An Ambassador
Take JCE along on your outreach missions. Copies of the Journal, guest access to JCE Online, our publications catalog, and more are available for your participants.
 Outreach with JCE

Comments to
jceonline@chem.wisc.edu		 Copyright © Division of Chemical Education, Inc., American Chemical Society.
All rights reserved.