Abstract
In the anion of the title compound, C(5)H(12)N(+)center dot C(10)H(8)NO(5)S(-), the thiazine ring adopts a distorted half-chair conformation and the enolic H atom is involved in an intramolecular O-H center dot center dot center dot O hydrogen bond, forming a six-membered ring. The anions and cations are connected via N-H center dot center dot center dot N and N-H center dot center dot center dot O interactions.