title: Hydro-nium 4-oxo-1,4-dihydro-pyridine-3-sulfonate dihydrate.
abstract: 2-Hydroxy-pyridine when treated with concentrated sulfuric acid is sulfonated at the 3-position to yield the title hydrated salt, H(3)O(+)·C(5)H(4)NO(3)S(-)·2H(2)O. In the crystal structure, the cations, anions and uncoordinated water mol-ecules are linked by extensive O-H⋯O and N-H⋯O hydrogen bonds into a three-dimensional network. The crystal studied is a non-merohedral twin with a twin component of 36%.
authors.forename: Zhi-Biao
authors.initials: ZB
authors.lastname: Zhu
authors.forename: Shan
authors.initials: S
authors.lastname: Gao
authors.forename: Seik Weng
authors.initials: SW
authors.lastname: Ng