This article presents the evidence of possible route to the formation of ε-and α-polymorphic phases of 2, 4,6,8,10,4,6,8,10, studied through CL-20 solution using reverse and normal precipitation method. Reverse precipitation with instant addition facilitated with the opportunity to track the crystal phases from their immediate formation to end of phase stabilization. Precipitation under apparent conditions to achieve α-or ε-phases, showed initial occurrence of metastable β-phase and subsequent transformation to the intended stable phases. The β-phase showed sufficiently longer stability while under specified conditions for ε-than in a hydrated medium set to obtain the α-phase.Transformation of fine needle shaped β-CL-20 crystals to uniform diamond shaped α-or bipyramidal ε-habit had been observed to pass through an equilibrium state of dissolution and reprecipitation. This work also elaborates the effect of crystallization methodology on conversion time. Vibrational spectroscopy and microscopic techniques were employed to track the time dependent polymorphic conversions. Drastic reduction in β → ε conversion time, from 160 minutes to 10 minutes could have been affected by using ultra dispersed seed crystals. We thus also demonstrated a hazard free non-grinding method to prepare ε-CL-20 with particle size <10 µm through precipitation and their effect on thermal stability & mechanical sensitivity.

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