Wikipedia
Hexanitrohexaazaisowurtzitane , also called HNIW and CL-20, is a nitroamine explosive with the formula CHNO. The structure of CL-20 was first proposed in 1979 by Dalian Institute of Chemical Physics. In 1980s, CL-20 was developed by the China Lake facility, primarily to be used in propellants. It has a better oxidizer-to- fuel ratio than conventional HMX or RDX. It produces 20% more energy than traditional HMX-based propellants, and is widely superior to conventional high-energy propellants and explosives.
Industrial production of CL-20 was achieved in China in 2011, and it was soon fielded in propellant of solid rockets. While most development of CL-20 has been fielded by the Thiokol Corporation, the US Navy (through ONR) has also been interested in CL-20 for use in rocket propellants, such as for missiles, as it has lower observability characteristics such as less visible smoke.
CL-20 has not yet been fielded in any production weapons system, but is undergoing testing for stability, production capabilities, and other weapons characteristics.