Inertness of the [Re6Se5Cl3](5+) cluster core to substitution by OH- in organic solutions: synthesis, structural and liquid secondary ion mass spectroscopy characterization of K(H2O)(2)[Re6Se5Cl9] and (n-Bu4N)[Re6Se5Cl9] andthe crystal structure of (n-Bu4N)(2)[Re6Se6Cl8]

When ethanol solutions of K[Re6Se5Cl9] are allowed to crystallize, the comp ound formulated K(H2O)(2)[Re6Se5Cl9] (1) is obtained. Extensive characteriz ation, which includes chemical analysis, X-ray structure determination and liquid secondary ion mass spectrometry (LSIMS), supports this formulation, which differs from that proposed earlier, K[Re6Se5(OH)(2)Cl-7].H2O. This co nclusively demonstrates that no substitution of an inner mu -core halogen b y OH- occurs within the cluster core. This is discussed and shown to be ful ly consistent with the present well-documented chemistry, which requires th at substitutions of halogen by divalent elements only are allowed. The pape r is complemented by the crystal structures of (n-Bu4N)[Re6Se5Cl9] and (n-B u4N)(2)[Re6Se6Cl8], which had not yet been properly reported.