The differential scanning calorimetry diagram of [Li-0.2(NH4)(0.8)](2)TeCl6 showed one anomaly at 526 K accompanied with a shoulder at 505 K. The conductivity plot exhibits two anomalies at 496 and 526 K, which characterize the beginning and the end of the crossing to superionic conductor state. The low temperature conduction is ensured essentially by Li+. A sudden jump confirms the presence of a superionic protonic transition related to the fast motion of Li+ and H+ ions. Above 526 K, the high temperature phase is characterized by high electrical conductivity (10(-3) Omega(-1) m(-1)) and low activation energy (E-a < 0.3 eV). The dielectric constant evolution as a function of frequency and temperature revealed the same anomaly. Transport properties in this material appear to be due to Li+ and H+ ions' hopping mechanism. (c) 2005 Elsevier B.V. All rights reserved.