Crystal structure and Hirshfeld surface analysis of 2-amino-3-hy-droxy-pyridin-1-ium 6-methyl-2,2,4-trioxo-2H,4H-1,2,3-oxa-thia-zin-3-ide.

The asymmetric unit of the title compound, C5H7N2O+·C4H4NO4S-, contains one cation and one anion. The 6-methyl-2,2,4-trioxo-2H,4H-1,2,3-oxa-thia-zin-3-ide anion adopts an envelope conformation with the S atom as the flap. In the crystal, the anions and cations are held together by N-H⋯O, N-H⋯N, O-H⋯O and C-H⋯O hydrogen bonds, thus forming a three-dimensional structure. The Hirshfeld surface analysis and fingerprint plots reveal that the crystal packing is dominated by O⋯H/H⋯O (43.1%) and H⋯H (24.2%) contacts.