4-[4-(4-Amino-1,2,5-oxadiazol-3-yl)-1,2,5-oxadiazol-3-yl]-1,2,5-oxadiazol-3-amine

The complete molecule of the compound, C₆H₄N₈O₃, is generated by a crystallographic twofold rotation axis that runs through the central ring. The flanking ring is twisted by 20.2 (1)° with respect to the central ring. One of the amino H atoms forms an intra­molecular N—H...N hydrogen bond; adjacent mol­ecules are linked by N—H...N hydrogen bonds forming a chain running along [10-2].

2-tert-Butyl-1-(4-nitro­amino-1,2,5-oxadiazol-3-yl)diazene 1-oxide

In the title compound, C₆H₁₀N₆O₄, the nitro­amine –NHNO₂ substituent and the C–N=N(→ O) unit of the other substituent of the oxadiazole ring are nearly coplanar with the five-membered ring [dihedral angles = 5.7 (1) and 3.0 (1)°]. The amino group of the –NHNO₂ substituent is a hydrogen-bond donor to the two-coordinate N atom of the C—N=N(→ O) unit.