G2ZT is a bistetrazole. It is an explosive approximately as powerful as RDX, but releases biodegradable reaction products when detonated: ammonia and hydrogen cyanide. When combined with ADN or AN oxidizers, the amount of HCN produced by a deflagration may be reduced. The compound is thus considered by its advocates to be an environmentally friendlier explosive than traditional nitroamine-based explosives. G2ZT is otherwise known as bis(3,4,5-triamino-1,2,4-triazolium) 5,5'-azotetrazolate.
References
Further reading Klapötke, Thomas M.; Sabaté, Carles Miró (2008). "Bistetrazoles: Nitrogen-Rich, High-Performing, Insensitive Energetic Compounds". Chemistry of Materials. 20 (11): 3629. doi:10.1021/cm703657k.