Experimental reports on mono-substituted Keggin, [M(Ligand)XW11O39] q-, and Wells-Dawson, [M(Ligand)X2W17O61] q-, syntheses are extensive. However, characterisation of these compounds and their corresponding ligands have proven difficult. An early example corresponds to the mono-substituted Ru-based Keggin involving the treatment of [SiW11O39] 8-with hydrated ruthenium(III) chloride, RuCl3•xH2O. Later, cyclic voltametric experiments suggested a mixture of undefined products as the hydrated ruthenium(III) chloride contained an assortment of ruthenium species present in different oxidation states. Since then, more labile precursors i.e. [Ru(dmso)4Cl2] and [Ru(H2O)6] 2+ 12 are employed with well-defined terminal ligands (aqua or sulfoxide ligands).