Hexameric polyoxotantalate with proton conduction properties.

The first Fe-implanted polyoxotantalate (POTa), K 12 Na 14 H 7.4 [Fe 10.7 Ta 1.3 O 8 (OH) 8 (H 2 O) 2 (Ta 6 O 19 ) 6 ]·114.5H 2 O (1), has been obtained by self-assembly in alkaline solution. The polyanion consists of six Lindqvist-type {Ta 6 } units linked together by {Fe 10.7 Ta 1.3 }. The compound not only possesses the highest nuclearity transition metal-oxygen cluster, but also has the highest degree of polymerization in the POTa field to date. And 1 possesses remarkable proton conduction.