Hexanitrohexaazaisowurtzitane

2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane, also called HNIW and CL-20, is a nitroamine explosive, 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.

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 (e.g., less visible smoke).

CL-20 has not yet been fielded in any production weapons system, but is presently undergoing testing for stability, production capabilities, and other weapons characteristics.

All testing up to date indicates that despite great power, CL-20 is hyperactively sensitive, to the point that almost no American explosive manufacturer will produce it in bulk. Accidental initiation is very common, and before CL-20 gains prominence this issue must be addressed.

It is made from N,N-dimethylformamime, acetic anhydride, HBIW and white fuming nitric acid by combining these chemicals.