Hexanitrohexaazaisowurtzitane (CL-20) and CL-20-based formulations (review)

This paper reviews the research and development work on CL-20, the most powerful high-energy material of today, as well as CL-20-based formulations. Methods of CL-20 synthesis and processes for obtaining a desired particle size are discussed. Particular attention is paid to optimization of conditions for obtaining the most stable high-density polymorph. The Fourier Transform Infrared spectroscopy and X-ray diffraction appear to be effective means for distinguishing CL-20 polymorphs. The thermal decomposition pattern of CL-20 as well as the proposed decomposition and combustion mechanisms also form part of this manuscript. Investigations performed by various researchers show that its relatively high sensitivity needs special attention from the viewpoint of CL-20 preparation and processing of formulations based on this substance. Salient features of CL-20-based explosives and gun/rocket propellants studied are included into this review. CL-20 may be ranked as the most attractive compound for futuristic explosive and propellant formulations. The research activities performed by the authors on synthesis and characterization of CL-20 are briefly described.