The thermal decomposition of a ZrTi2[(OC2H4)2NH]3(OC3H7)6 precursor by the RAPET (reaction under autogenic pressure at elevated temperature) method provided the formation of crystalline zirconium titanate nanoparticles. These as-prepared nanoparticles are embedded in a carbon shell, which can be removed completely by calcination at 500 °C under air for 3 h, resulting in pure white crystalline nanoparticles. At a reaction temperature of 700 °C, the nanoparticles are mainly ZrTi2O6 (srilankite), whereas at 800 °C, the product is predominately Zr5Ti7O24. The structural, morphological, compositional, magnetic, and AC electrical properties are measured for the as-prepared ZrTi2O6 embedded in carbon (ZTEC), as well as the crystalline ZrTi2O6 nanoparticles (ZTN) obtained after sintering. The reaction mechanism is based on the decomposition products containing pyrrol and pyrazine. The presence of these compounds provides an understanding of the decomposition of the diethanolamine ligands and the formation of the nanoparticles in general.