An electron spin resonance study of the dinitrogen tetroxide radical cation

Abstract

Exposure of dilute solutions of dinitrogen tetroxide in CFCl₃ to ⁶⁰Co γ-rays at 77 K gave the radical cation [N₂O₄]⁺. The e.s.r. spectrum of this cation closely resembles that for NO₂˙, except that A_iso(¹⁴N) is slightly increased. Small extra splittings are discussed in terms of very weak hyperfine coupling to the second nitrogen. The structure can be thought of as being NO₂˙ strongly perturbed by linear NO₂⁺ cations. This conclusion is in agreement with recent ab initio calculations. The results are compared with previous studies of irradiated crystalline dinitrogen tetroxide.