Abstract Tin doped In 2TeO 6 is prepared at 700° C as a n-type semiconductor. Its carrier mobility is less than 10 −3 cm 2/Vs. From photo-electrochemical experiments the optical transition across the band gap is determined to be direct forbidden at 1.56 eV. A further indirect allowed transition occurs at 2.93 eV. The electron affinity of In 2TeO 6 is 4.5 eV.