Reaction of thiamine chloride hydrochloride (TCl . HCl) (vitamin B 1 hydrochloride) with SnMe 2 Cl 2 and SnPh 2 Cl 2 in 9:1 v/v ethanol-water afforded the salts (HT)[SnMe 2 (H 2 O)Cl 3 ]Cl (I) and (HT)[SnPh 2 Cl 4 ]H 2 O (II) respectively. Both compounds were characterized by mass spectrometry and by IR and Raman spectroscopy, and the crystal structures of both were determined by X-ray diffraction. I crystallizes in the monoclinic space group P2 1 n; the thiaminium cation adopts the F conformation, and in the anion the tin atom co-ordinates to two trans C atoms of methyl groups, three Cl atoms and the O atom of a water molecule in a distorted octahedral arrangement. II crystallizes in the triclinic space group P1; the thiaminium cation adopts the S conformation, and there are two kinds of [SnPh 2 Cl 4 ] 2 - anion, one placed between two cations with its phenyl groups stacking over their pyridine rings, and the other without a close relationship with any cation. The two Sn atoms lie on a crystallographic inversion centre and have a separation of (0.5, 0.5, 0.0). Several hydrogen bonds are present in both structures, as well as S ... O electrostatic interactions in II.