Key indicators: single-crystal X-ray study; T = 100 K; mean (C-C) = 0.001 Å; R factor = 0.034; wR factor = 0.096; data-to-parameter ratio = 15.5.In the title compound, ExperimentalCrystal data

In the title compound, 2C3H5N2S+·C4H4O4 2−·C4H6O4, the thia­zolium ring is almost planar, with the maximum deviation from planarity being 0.0056 (8) Å for the C atom carrying the amine substituent. The N atom of the 2-amino­thia­zole mol­ecule is protonated. Both the anion and the acid lie across inversion centres. The crystal packing is consolidated by inter­molecular O—H⋯O, N—H⋯O and C—H⋯O hydrogen bonds. Mol­ecules are stacked down the b axis.

In the title salt, C5H7N2 +·C4H5O4 −, the asymmetric unit comprises an amino­pyridinium cation and a hydrogen succinate anion as protonation of the aromatic N atom of the 4-amino­pyridine mol­ecule has occurred. The crystal packing is stabilized by inter­molecular O—H⋯O and N—H⋯O hydrogen bonds that lead to a two-dimensional array. Short C—H⋯O contacts are also present.

Maleic acid and fumaric acid, the Z and E isomers of butenedioic acid, form 1:1 adducts with 2-amino-1,3-thiazole, namely 2-amino-1,3-thiazolium hydrogen maleate (2ATHM), C(3)H(5)N(2)S(+) x C(4)H(3)O(4)(-), and 2-amino-1,3-thiazolium hydrogen fumarate (2ATHF), C(3)H(5)N(2)S(+) x C(4)H(3)O(4)(-), respectively. In both compounds, protonation of the ring N atom of the 2-amino-1,3-thiazole and deprotonation of one of the carboxyl groups are observed. The asymmetric unit of 2ATHF contains three independent ion pairs. The hydrogen maleate ion of 2ATHM shows a short intramolecular O-H...O hydrogen bond with an O...O distance of 2.4663 (19) A. An extensive hydrogen-bonded network is observed in both compounds, involving N-H...O and O-H...O hydrogen bonds. 2ATHM forms two-dimensional sheets parallel to the ab plane, extending as independent parallel sheets along the c axis, whereas 2ATHF forms two-dimensional zigzag layers parallel to the bc plane, extending as independent parallel layers along the a axis.

The asymmetric unit of the title compound, [Ag(C5H6N2)2]NO3, consists of one and a half each of both cations and anions, the other halves being generated by crystallographic inversion centres. One of the AgI atoms lies on an inversion center and one of the nitrate ions is disordered across an inversion center. Each AgI atom is bicoordinated in a linear geometry by two N atoms from two 2-amino­pyridine ligands. In the crystal structure, the cations and anions are linked into a two-dimensional network parallel to (001) by N—H⋯O and C—H⋯O hydrogen bonds.