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Chemistry LibreTexts

Isotopes: Br and Cl

  • Page ID
    4182
  • bromoethane.gif
    Figure MS5. Mass spectrum of chlorobenzene.

    Source: SDBSWeb : http://riodb01.ibase.aist.go.jp/sdbs/ (National Institute of Advanced Industrial Science and Technology of Japan, 22 August 2008)

    • Chlorinated compounds show an M+2 peak that is 1/3 as large as the M+ peak.

    Note also that halogens are easily lost during mass spectrometry. If you subtract the mass of the halogen from the molecular ion mass, you will often find a peak that corresponds to the remainder of the structure.

    Problem MS4.

    Draw one possible structure for the compound in each of the following mass spectra.

    ms iso2.gif

    ms iso3.gif

    ms iso4.gif

    Source: SDBSWeb : http://riodb01.ibase.aist.go.jp/sdbs/ (National Institute of Advanced Industrial Science and Technology of Japan, 25 August 2008)

    Problem MS5.

    In the following mass spectrum, more than one halogen atom is present.

    1. What is a possible structure of the compound?
    2. Show why this pattern of molecular ions is observed.

    ms iso5.gif

    Source: SDBSWeb : http://riodb01.ibase.aist.go.jp/sdbs/ (National Institute of Advanced Industrial Science and Technology of Japan, 25 August 2008)