catena-Poly[[bis­(di­aqua­lithium)]-μ4-3,3′,5,5′-tetra­nitro-4,4′-bi­pyrazole-1,1′-diido]: a new moisture-insensitive alkali-metal energetic salt with a well-defined network structure

In the title salt, the 3,3′,5,5′-tetra­nitro-4,4′-bi­pyrazole-1,1′-diide dianion [{TNBPz}2−] is situated across the twofold axis. The distorted coordination octa­hedra around Li+ involve four short bonds with two pyrazolate N atoms and two aqua ligands and two longer contacts with nitro-O atoms. When combined with μ4-{TNBPz}2−, this generates a mono-periodic polymeric structure incorporating discrete centrosymmeric [(H2O)2Li–(di­nitro­pyrazolato)2–Li(H2O)2] units. The three-dimensional stack of mutually orthogonal coordination chains is reminiscent of a Lincoln log pattern.