C 10 H 9 I 3 N 2 S 2 ,monoclinic, C 12/c 1(no. 15), a =16.4841(9) Å, b =9.6845(7) Å, c =13.0227(9) Å, b =127.309(2)°, V =1653.6 Å 3 , Z =4, R gt (F) =0.068, Source of materialThe title compound was preparedbythe mixture of pyridine-2-thiol (PySH,1mmol) and nickel iodide (0.5 mmol) was dissolved in hot ethanol-water (25 ml; 3:2, v / v )a nd stirred at 353 Kfor 30 min and then filtered. After allowing the solution to stand for about two weeks, brown block-like crystalsofthe title compound were formed unexpectedly. DiscussionThe title crystal structure consists of [C 10H 9 N 2 S 2 ] + cations and [I 3 ] -anions. Two PySH ligands couple together through the Satoms with S-Sdistance of 2.04(2) Åand the angle of two pyridinering planes is 29.7°. [I 3 ] -anions are regularly arranged around the cations. Inaddition, there are relativelyshort distances (centroid separation of 3.648(4) Å,interplanar spacing of 3.542(4) Å)between the pyridine-ring plane and the symmetry-related plane at ( 3 ¤ 2 -x, 3 ¤ 2 -y ,1-z )inanadjacent cation, implying weak p -p interactions in this structure. The structure of the title compound represents asecond modification to aknown phase crystallizing in P 2 1 [1], which was synthesized by oxidation/dimerization of pyridine-2-thiol with diiodine in dichloromethane. The reason for the two modifications is adifferent crystal packing caused by different intermolecular bonds. Inthe title structure, each terminal Iatom of the [I 3 ] -anion forms two hydrogen bonds with the 4-site and 6-site pyridyl Catoms with C···Idistances of 3.952(2) Åand 4.008(2) Å,respectively. Inthe already published structure[1], the 6-site Catoms of the four independent [C 10 H 9 N 2 S 2 ] + cations form Hbonds to the central Iatoms with