Based on testing of different cation salts of the three main anion species (nitrates, chlorates and perchlorates) and supported by external references, the main points are:
1. Nitrates, chlorates and perchlorates are generally differentiated from each other based on the anion class. Both CBRNE and IABTI lists appear to recognize this and only list the general anion class with cations in brackets as general types. For example: an instrument identifies nitrates (K/Ca).
2. The identification of the nitrates, chlorates and perchlorates may not be selective with the specific cation as some of these may not be differentiated due to changes in physical parameters, limitations of resolution of portable instruments, or sources of noise in the scan or sample. As well for a subclass of cation salts with cation effect is just not sufficient to shift the peaks and allow differentiation.
3. Ammonium nitrate is a special case which makes it difficult to selectively identify with Raman spectroscopy. The additional spectral peaks due to the N-H are small and easily dominated by changes due to physical changes. While identified as a nitrate, selectivity of the cation is not always possible due to peak shifts/changes.
4. When building a library to identify chlorates, perchlorate or nitrate material for safety and security applications, it is recommended that library quality, traceable salts are obtained. As most nitrates, chlorates and perchlorates actually tested in the field are not of the same quality, the results should be used in such a way that recognizes the specific type of anion, but does not assume selectivity of the cation. For example, results should state nitrate salts, but allow for possible cations (calcium, potassium, or ammonium).