2-Aminoanilinium phosphite.

The solid-state structure of the title compound, alternatively called 2-aminoanilinium hydrogen phosphonate, C(6)H(9)N(2)(+).H(2)PO(3)(-), shows the monoprotonated diamine molecule to be multiply hydrogen bonded to HPO(3)H(-) anions. There is no inter-phosphite hydrogen bonding, contrary to previous solid-state observations of the species.