4-Bromo-pyridinium tri-chlorido-stannate(II)

Single crystals of the title salt, (C₅H₅BrN)[SnCl₃] or [4-BrPyH][SnCl₃], were prepared from aqueous solutions of 4-bromo-pyridinium hydro-chloride, [4-BrPyH]Cl, and tin dichloride, SnCl₂. The cation has bond lengths and angles similar to those found in its other salts. In its first coordination sphere, the anion has a trigonal-pyramidal, tpy, structure with the Sn^II atom at the apex and the three chlorine atoms at the base. The tin-chlorine bond lengths are all greater than 2.5 Å and the bond angles are all less than 92°, which indicates the presence of tetrel bonds. These occur along the twofold screw-axis in the b-axis direction and extend the coordination sphere of the tin atom to a highly distorted, 3₃-aaa octa-hedron. In the crystal, the cations are stacked parallel to one another at varying distances along the a-axis direction, with weak π-π inter-actions occurring on both sides. Additional N-H⋯Cl hydrogen bonds are bifurcated and weak.