The crystal structure of Ca(II) (pyrazine-2,3-dicarboxylate) tetrahydrate chloride

Crystals of catena-[(tetraqua-O)(μ-hydrogen pyrazine-2,3-dicarboxylate-N,O,N′,O′)calcium(II)] chloride contain molecular ribbons composed of polycations and chloride Cl− anions. Two adjacent Ca(II) atoms are bridged by a ligand molecule which uses both its N,O bonding moieties. One of the carboxylic groups retains its hydrogen atom which takes part in a short [D–H···A 2.378(2) A] intramolecular hydrogen bond. The coordination polyhedron around Ca(II) is a distorted pentagonal bipyramid with two apices on one side of the pentagonal equatorial plane and one apex on the other. Chloride anions are located in the interstitial space between the ribbons.