Solid-state synthesis of compositions from the Bi2O3-TeO2 system show that, under an oxygen atmosphere, Te4+ oxidizes to Te6+ and yields four room-temperature stable compounds: Bi2Te2O8, Bi2TeO6, Bi6Te2O15, and new a compound with the nominal composition 7Bi2O3.2TeO2. Dense ceramics can be prepared from all these compounds by sintering between 650 degrees and 800 degrees C under an oxygen atmosphere. The permittivity of these compounds varies from 30 to 54, the Q x f value from 1.100 to 41.000 GHz (5 GHz), and the temperature coefficient of resonant frequency from -43 to -144 ppm/K. Bi6Te2O15 and 7Bi2O3.2TeO2 do not react with silver, and, therefore, they have the potential to be used for applications in low-temperature cofired ceramic (LTCC) technology. PUBLICATION ABSTRACT