Time-differential perturbed angular correlations investigation of the (NH4)2ZrF6 thermal decomposition

Via the TDPAC technique and complementary x-ray diffraction analysis, the thermal decomposition of (NH4)2ZrF6 has been observed to occur in the range 400–800 K according to the thermolysis scheme (NH4)2ZrF6→485 KNH4ZrF5→560 KNH4Zr2F9 →620 KZrF4→760 KZrO2. Assuming that the first transformation takes place through the simple chemical reaction (NH4)2ZrF6→NH4ZrF5+NH4F, the corresponding activation energy has been determined to be Ea=(82±6) kJ/mol. The hyperfine parameters of the NH4Zr2F9 decomposition product have been determined between 14 and 560 K. A complete analogy with the isomorphous compound NH4Hf2F9 was observed.