Aminoguanidinium Fluorozirconates: Improved Synthesis and Thermal Decomposition of CN4H8ZrF6, CN4H8ZrF6·1/2H2O, CN4H8ZrF6·H2O, (CN4H7)2ZrF6, and CN4H7ZrF5

Synthesis of the title compounds by present literature methods produces compositional mixtures that are difficult to separate. Controlled temperatures, times, and reactant concentrations produce gram quantities of pure, colorless, transparent crystals. Thermogravimetry and differential scanning calorimetry show that heating to 400 °C in a nitrogen atmosphere causes stepwise decomposition involving first the loss of water (for the hydrated compounds), followed by liberation of HF, then decomposition to ZrF4.