|MadSci Network: Chemistry|
You are correct in having identified both NO, nitric oxide, and NO2, nitrogen dioxide or nitrogen peroxide, as paramagnetic due their both having an unpaired electron.
Both species lose this electron relatively easily, their respective ionization potentials being 9.23 eV and 9.91 eV. On this basis, NO is the slightly more reactive.
What is more interesting is the chemistry of the species thus formed: NO+ (the nitrosonium ion) and NO2+ (the nitronium ion). Both form ionic salts, such as NO+HSO4- and NO2+ClO4-. NO2+ is the "active" species in nitration reactions of organic compounds.
NO and NO2 do differ, however, in their propensity to dimerize. NO only does so feebly, but NO2 forms N2O4 readily at room temperature and below. The latter readily forms radicals NO. and NO.3 thereby contributing to (NO2) 2 having a greater reactivity than NO towards susceptible materials.
I hope that answers your question. Thanks for using the Mad Scientist Network.
Bibliography: Advanced Inorganic Chemistry, F.A.Cotton & G. Wilkinson, Interscience Publishers, 3rd ed., 1972, ISBN 0-471-17560-9
Webography:Chemistry 242 - Inorganic Chemistry II Chapter 16 - Nitrogen
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