Structures of Sodium Hydrogen l-Tartrate Monohydrate and Potassium Hydrogen l-Tartrate

Abstract

Abstract Crystals of sodium hydrogen l-tartrate monohydrate (NaHC4H4O6·H2O) were grown from the aqueous solution, while potassium hydrogen l-tartrate (KHC4H4O6) crystallized as anhydrate. Their crystal structures were determined by X-ray diffraction method. The hydrogen bonds between the carboxyl and carboxylate groups in these crystals are rather long; O···O 2.533(3) and 2.531(1) Å for the sodium and potassium compounds, respectively. The sodium and potassium ions are coordinated by eight O atoms at the corners of distorted square antiprism, Na+···O 2.404(2)—2.826(3) Å and K+···O 2.718(1)—3.059(1) Å. The crystal and molecular structures have been compared with those of the corresponding rubidium, caesium, and ammonium salts, and discussed with the aid of semiempirical and ab initio MO methods.