Simultaneous DSC/TGA studies of CsNO

CsNO₃ is one of a group of Nitrates that have been studied extensively due to their interesting polymorphic transformations at various temperatures. It is also of interest as an oxidizer for pyrotechnic compositions and exhibits pyroelectric behavior at low temperatures. Literature information on its melting point as well as its solid to solid transition varies as much as 10 degrees Celsius.  In this work, high purity (99.99%) CsNO₃ were studied using a TA Instruments SDT Q600 Simultaneous Differential Calorimeter/Thermogravimetric Analyzer (DSC/TGA).  The DSC/TGA measured the heat flow simultaneously with mass changes of the CsNO₃ as a function of temperature from room temperature to 520 C˚ at heating rates varying between 2.5 and 25 C˚/min.  Two observed points of interest are the solid to solid transition and a melting transition occurring around 154 C˚ and 406 C˚ respectively.  The Universal Analysis software was used to obtain the onset and peak transition temperatures, and other values. The Zero heating rate method, in which the transition temperatures are obtained by extrapolation to zero heating rate, was used to ascertain more precise transition temperatures.  These results and some observed events at the melting point will be the primary focus of the presentation.