A team of researchers argues that the nitrate anion can display a counterintuitive Lewis acidity. Their findings may serve as a (retrospective) guide to interpret data involving the chemical ...

However, when larger or more complex anions enter, like nitrate or formate, their shapes can disrupt the pocket structure, and the ions stick out into the surrounding solvent.

Vicente Martí-Centelles, Paul D. Beer. Nitrate Anion Recognition in Organic-Aqueous Solvent Mixtures by a Bis(triazolium)acridine-Containing [2]Rotaxane. Chemistry - A European Journal , 2015; 21 ...