Bis(5-amino-3-carb-oxy-1H-1,2,4-triazol-4-ium) dihydrogenphosphate nitrate 5-amino-1H-1,2,4-triazol-4-ium-3-carboxyl-ate.

In the title compound, 2C(3)H(5)N(4)O(2) (+)·H(2)PO(4) (-)·NO(3) (-)·C(3)H(4)N(4)O(2), three independent 5-amino-1H-1,2,4-triazol-3-carb-oxy-lic acid moieties are observed. Two are in the form of cations, while the third is in the zwitterionic form. The triazole rings in the two cations are almost coplanar, making an angle of 4.11†(7)°. Layers parallel to the (20-1) plane, resulting from hydrogen bonding of the organic mol-ecules and the nitrate anions, are linked via H(2)PO(4) (-) infinite zigzag chains running parallel to the c axis. The crystal studied was an inversion twin, with refined components of 0.33†(7) and 0.67†(7).