Helionitronium trication (NO(2)He(3+)) and helionitrosonium trication (HeNO(3+))

The structures and stabilities of helionitronium trication NO(2)He(3+) and helionitrosonium trication HeNO(3+) were calculated at the ab initio MP2/6–31G** level. The C(s) symmetry structure was found to be a minimum for the NO(2)He(3+) trication, which is isoelectronic and isostructural with the previously studied NO(2)H(2+). Dissociation of the C(s) symmetry structure into NO(+) and OHe(2+) is thermodynamically preferred by 183.1 kcal/mol (1 cal = 4.18 J), although a kinetic barrier of 12.4 kcal/mol has to be overcome. The C(∞v) symmetry structure was also found to be a minimum for the HeNO(3+) trication.