Sodium, potassium, rubidium, caesium, ammonium and tetramethylammonium tetraphenylborates were studied by both positive and negative ion electrospray mass spectrometry. An affinity order of Cs+> Rb+> K+∼ Na+ was obtained. The results obtained were compared with both calculations and solid-state structures, where available. The previously reported high affinity of caesium for tetraphenylborate concluded from NMR ...
