Crystal structure of bis(3-carboxy-1-methylpyridinium) octabromide

The crystal structure of the title salt, bis(3-carboxy-1-methylpyridinium) octa-bromide, 2C(7)H(8)NO(2)(+) center dot Br-8(2-), consists of 3-carboxy- 1-methylpyridinium (N-methylnicotinic acid) cations, which are stacked between relatively rare [Br8]2- anions. The polybromide [Br-8](2-) anion has point group symmetry 1 ($) over bar and can be described as being composed of two [Br-3](-) anions connected with a Br-2 molecule in a Z-shaped manner. Contacts between neighboring octabromide anions ensure the creation of pseudo-polymeric chains propagating along [111]. The organic cations are located between anionic chains and are connected to each other through O-H center dot center dot center dot O hydrogen bonds and to the [Br-8](2-) anions through pi center dot center dot center dot Br interactions that induce the creation of a supramolecular triperiodic network. In addition, the presence of weak C-H center dot center dot center dot Br contacts leads to the creation of layers, which align parallel to (112 ($) over bar).