Ultrafine particles of IrO2-SnO2 binary oxides have been prepared by a
sol-gel process consisting of hydrolysis and condensation of metal al
koxide alcoholic solutions. The rutile-type oxide solid solution of bi
nary oxides, (Ir, Sn)O2 was formed after the calcination at 450-degree
s-C. The a and c lengths of the lattice parameters linearly decreased
with the increase of the iridium content. The Ir-Sn binary oxides were
crystallized to the (Ir, Sn)O2 rutile-type phase at lower temperature
than the iridium oxide to IrO2.