The thermoanalytical curves of (C6H5)4AsCl (I) and (C6H5)4PCl (II) were generated simultaneously by using a Netzsch simultaneous thermal analyser 409 under static air and dynamic argon
atmospheres. The ranges of thermal stability of I and II were found to be 145–310°C and 137–365°C, respectively, and their
melting points to be 261 and 278°C. The DTA profiles of I and II differ and can be used for their distinction.