Radical ion

DRAFT DEFINITION
Radical ion
An ion, either a cation or anion, containing unpaired electrons in its ground state. The unpaired electron is denoted by a superscript dot alongside the superscript symbol for charge, such as for the molecular ion of a molecule M, that is, M+?????????????????????. Radical ions with more than one charge and/or more than one unpaired electron are denoted such as M(2+)(2?????????????????????).Unless the positions of the unpaired electron and charge can be associated with specific atoms, superscript charge designation should be placed before the superscript dot designation.
Considered between 2004 and 2006 but not included in the 2006 PAC submission
This is an unofficial draft definition presented for information and comment. Recommended terms | Full list of terms

Orange Book Entry

This is an ion containing an unpaired electron, which is thus both an ion and a radical. In mass spectroscopy an unpaired electron is denoted by a superscript dot alongside the superscript symbol for charge, thus C₂H₆^{+?????????????????????} or SF₆ ^{-?????????????????????}. An alternative form (IUPAC Compendium of Chemical Terminology, 1987) used in inorganic and organic chemistry literature uses the symbolism as in X^{?????????????????????+}. For species with more than one charge and/or more than one unpaired electron the styles X^{(2+) (2?????????????????????)} or X^{(2?????????????????????) (2+)} are recommended.

Gold Book Entry

A radical that carries an electric charge. A positively charged radical is called a ' radical cation ' (e.g. the benzene radical cation C₆H₆ ^{?????????????????????+1} ); a negatively charged radical is called a ' radical anion ' (e.g. the benzene radical anion C₂H₆ <sup????????????????????? - or the benzophenone radical anion Ph₂C-O^{????????????????????? -} ). Commonly, but not necessarily, the odd electron and the charge are associated with the same atom. Unless the positions of unpaired spin and charge can be associated with specific atoms, superscript dot and charge designations should be placed in the order ^{?????????????????????+1} or ^{?????????????????????-} suggested by the name 'radical ion'. (e.g. C₃H₆^{?????????????????????+1} ).

Notes:

In the previous edition of this Compendium, it was recommended to place the charge designation directly above the centrally placed dot. However, this format is now discouraged because of the difficulty of extending it to ions bearing more than one charge, and/or more than one unpaired electron. In mass spectroscopic usage the symbol for the charge precedes the dot representing the unpaired electron.