1:2, 1:1, 3:2 and 6:2 AgX:L adducts (where L is a tridentate phosphine, in detail: 1,1,1-tris(diphenylphosphinomethyl)ethane (Metriphos) and bis(2-diphenylphosphinoethyl)phenylphosphine (Ph-triphos), X = O3SCF3, O3SCH3, BF4 or O2CCF3) have been synthesized and characterized by IR, NMR (H-1, P-31 and F-19) and ESI MS spectroscopy. The stoichiometry of the complexes is strongly dependent on the ligand to metal ratio employed and also on the nature of the counterion. P-31 NMR (solution) data also show the complexes existing in solution, in some cases, however, disproportionating to adducts of different nuclearity. Oligonuclear species have been detected through ESI MS spectroscopy that has been demonstrated as a powerful tool for the identification of the solution species. AgBF4:Me-triphos (1:2) has been structurally characterized as [Ag(P,P'-Me-triphos)(2)](BF4) (.) H2O (.) 7/2 MeOH, while Ag(O3SCF3): Ph-triphos: H2O (6:2:4) is a spectacular two-dimensional polymer. (c) 2005 Elsevier B.V. All rights reserved.