Thermal hazard of iron picrate.

Iron picrate (FePic) was synthesized under conditions similar to those that result in the natural deterioration of chemical weapons. Its thermal hazard was investigated by comparing it with iron picrate obtained by the chemical synthesis method (FePic(Ba)). FePic has eight or more water molecules of crystallization and consists of a mixture of various hydrates. It shows low sensitivity to friction and drop hammer tests due to the large number of water molecules of crystallization. Under the experimental conditions of the thermal analysis, the hydrated iron picrates began to decompose before being dehydrated to form the anhydrous salt. Prolonged holding under natural environmental conditions does not appear to result in formation of the dangerous anhydrous salt. Based on the observed heating rate dependence, it is thought that the hydrated iron picrate should start to decompose before dehydration to the anhydrous salt occurs when subjected to a large heating rate.