The synthesis and structure of lithium and silver tetrakis(pentafluorophenyl)borate salts have been studied in different solvents ranging from polar (CH 2 Cl 2 , diethyl ether) to nonpolar (toluene, pentane). While Li[B(C 6 F 5 ) 4 ] is stable in all studied solvents and crystallizes with four ether molecules from ether and with two toluene molecules from toluene, the silver salt is only stable when the Ag þ ion is strongly coordinated such as in [Ag(tolueneIn weakly coordinating solvents such as CH 2 Cl 2 Ag[B(C 6 F 5 ) 4 ] decomposes, yielding AgC 6 F 5 and B(C 6 F 5 ) 3 . The overall process of the AgC 6 F 5 synthesis starting from B(C 6 F 5 ) 3 and LiC 6 F 5 can formally be regarded as a B(C 6 F 5 ) 3 -catalyzed reaction. The salt [Ag(toluene) 3 ][B(C 6 F 5 ) 4 ] presents an easily accessible, ether-free, stable silver salt of the [B(C 6 F 5 ) 4 ]anion. All compounds have been fully characterized. § Dedicated to Prof. Dr. Uwe Rosenthal on the occasion of his 60th birthday.

Double duty: The series of salts containing the bissilylated halonium cation [Me3SiXSiMe3]+ (X=F, Cl, Br, and I; see picture) has been generated and fully characterized in the super Lewis acidic silylating medium Me3SiX (as solvent and reactant) and [Me3Si][B(C6F5)4] (as silylating reagent).

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