Compositional studies of electrode films based on RuO2-TiO2 mixts., prepd. by pyrolytic oxidn. of RuCl3.3H2O-diisopropoxybis(2,4-pentanedionato)titanium deposits show that these materials contain large amts. of carbon and hydrogen impurities. This evidence supports the idea that crystallites of the RuO2-TiO2 solid soln. are sepd. by large amorphous areas where chem. impurities are accumulated. The porosity of these areas is responsible for the relatively high charge-storage capacity of the mixed-oxide electrodes found by voltammetry. [on SciFinder (R)]