Molecular ion: Difference between revisions

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An ion formed simply by the removal from (positive ions) or addition to (negative ions) a molecule of one or more electrons. For molecules containing multi-isotope elements, a number of different isotopologue ions will be formed, but the term molecular ion is restricted to the ion formed by the most abundant naturally occurring isotopes of all atoms that make up the molecule. For instance, electron ionization of BF<sub>3</sub> gives two isotopologue ions, <sup>10</sup>B<sup>19</sup>F<sub>3</sub><sup>+.</sup> of <i>m/z</i> 67 and <sup>11</sup>B<sup>19</sup>F<sub>3</sub><sup>+.</sup> of <i>m/z</i> 68, the heavier one being the molecular ion since <sup>11</sup>B is more abundant than <sup>10</sup>B. The mass of the molecular ion should be calculated by the sum of the masses of the most abundant naturally occuring isotopes of all its atoms with a correction for the masses of the electron(s) that were added or removed.
An ion formed simply by the removal from (positive ions) or addition to (negative ions) a molecule of one or more electrons. For molecules containing multi-isotope elements, a number of different isotopologue ions will be formed, but the term molecular ion is restricted to the ion formed by the most abundant naturally occurring isotopes of all atoms that make up the molecule. For instance, electron ionization of BF<sub>3</sub> gives two isotopologue ions, <sup>10</sup>B<sup>19</sup>F<sub>3</sub><sup>+.</sup> of <i>m/z</i> 67 and <sup>11</sup>B<sup>19</sup>F<sub>3</sub><sup>+.</sup> of <i>m/z</i> 68, the heavier one being the molecular ion since <sup>11</sup>B is more abundant than <sup>10</sup>B. The lighter ion is sometimes termed an isotopic molecular ion. The mass of the molecular ion should therefore be calculated by the sum of the masses of the most abundant naturally occuring isotopes of all its atoms with a correction for the masses of the electron(s) that were added or removed.


[[Category:Ions]]
[[Category:Ions]]
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[[Isotopologue Ion]]
[[Isotopologue Ion]]
[[Isotopic Molecular Ion]]
[[Base Isotope Cluster Ion]]

Revision as of 15:34, 3 February 2005

An ion formed simply by the removal from (positive ions) or addition to (negative ions) a molecule of one or more electrons. For molecules containing multi-isotope elements, a number of different isotopologue ions will be formed, but the term molecular ion is restricted to the ion formed by the most abundant naturally occurring isotopes of all atoms that make up the molecule. For instance, electron ionization of BF3 gives two isotopologue ions, 10B19F3+. of m/z 67 and 11B19F3+. of m/z 68, the heavier one being the molecular ion since 11B is more abundant than 10B. The lighter ion is sometimes termed an isotopic molecular ion. The mass of the molecular ion should therefore be calculated by the sum of the masses of the most abundant naturally occuring isotopes of all its atoms with a correction for the masses of the electron(s) that were added or removed.

Related Terms

Isotopologue Ion Isotopic Molecular Ion Base Isotope Cluster Ion