The low electrical conductivity (1.3 1013 1 cm 1 at 273 K) of liquid N2O4
is inconsistent with the presence of ions in the neat liquid. However, when [Et4N][NO3]
(which has a very low lattice energy) dissolves in liquid
N2O4, [NO3] ions rapidly exchange between the solute
and solvent. This confirms that [NO3] ions can form in
liquid N2O4. In terms of a solvent-oriented acid-base definition,
basic behaviour in N2O4 is characterized by the formation
of [NO3], and acidic behaviour by the production of
[NO]+. Thus, equilibrium 9.74 is useful for understanding
reactions in liquid N2O4, even though self-ionization does
not occur in the pure liquid.