October 24, 2020, 04:44:11 AM
Forum Rules: Read This Before Posting


Topic: Questions about IR spectrum of acetonitrile  (Read 166 times)

0 Members and 1 Guest are viewing this topic.

Offline OrganicH2O

  • Regular Member
  • ***
  • Posts: 40
  • Mole Snacks: +0/-0
Questions about IR spectrum of acetonitrile
« on: September 21, 2020, 04:45:09 PM »
I found this IR spectrum for acetonitrile on the Japanese Spectral Database: https://sdbs.db.aist.go.jp/sdbs/cgi-bin/direct_frame_top.cgi

I am wondering why acetonitrile has two stretching vibrations at about 2200. I don't think the CN triple bond would have a symmetric and asymetric stretch.

Also, it has stretching vibrations above 3000, including a sharp one at about 3200. It also has something that looks like a carbonyl overtone around 3500, but there is no corresponding strong stretch at about 1700. What's the deal there?

Offline mjc123

  • Chemist
  • Sr. Member
  • *
  • Posts: 1778
  • Mole Snacks: +252/-11
Re: Questions about IR spectrum of acetonitrile
« Reply #1 on: September 22, 2020, 04:54:42 AM »
That link just takes me to the database, not the spectrum.

The two peaks at ca. 2200 are due to a Fermi resonance, I think with the combination 1376 + 918. 3164 could perhaps be the combination 2253 + 918. 3500 sounds like water - the sample is not dry.

Sponsored Links