“…Finally, a low abundance, but above background ion was measured at m/z 2944.4, which would correspond to [16,23, [13,12,29] -, using the notation of this paper. Exactly seven dehydration reactions of [13,12,29] -would produce the observed [13,19,15] -; however, if this were occurring then the absence of any of the higher hydrates is puzzling. An alternative concept might be direct LA formation of a [13,19,15] -Ce Keggin that can accommodate additional water molecules, but is not further hydrated because of slow addition kinetics and weak binding, perhaps suggesting datively bound water, in which case the hydrated version should be rather written as [13,15,19,(H 2 O) 7 ] -.…”