Quantitative determination of ε-phase in polymorphic HNIW using X-ray diffraction patterns

An X-ray diffraction method was applied for the quantitative determination of the e-Hexanitrohexaazaisowurtzitane (HNIW) in polymorphs of HNIW. The XRD patterns of four polymorphs illustrate the unique nonoverlapping peak at 19.9" which belongs to ε-HNIW. The intensity ratio of the peak at 19.9° of ε-HNIW to the peak at 79.6° of α-Al ₂O₃ is proportional to the weight ratio of standard ε-HNIW to the internal standard of α-Al₂O₃, which enables the internal standard method. When the particle size of the sample is less than 10 μm, the content of ε-HNIW ranging from 70 to 100 wt.-% can be determined with an absolute error below 2.0%.