STRUCTURES OF THE HYDROGEN (+)-TARTRATES OF SODIUM, THALLIUM(I) AND SILVER(I)

The crystal structures of the sodium, thallium(I) and Silver(I) salts of hydrogen (+)-tartrate, Na+(HC4H4O6)-, (1), Tl+ (HC4H4O6)-, (2) and Ag+ .(HC4H4O6)-.H2O, (3) have been determined by X-ray diffraction and refined to residuals R = 0.033, 0.028 and 0.019 for 2038, 1009 and 651 observed reflections respectively. All structures are network polymers with metal centres involved in coordination to both carboxylate and hydroxyl oxygens of tartrate residues, and in the case of (3), to a single water. The anhydrous sodium compound, (1) differs from the common monohydrate in having distorted octahedral coordination about the metal, linking six different tartrate residues [4 carboxyl, 2 hydroxyl: Na-O range, 2.319(1)-2.460(1) angstrom]. The thallium(I) salt (2) is a member of an isomorphous series (which includes the NH4+, K+, Rb+ and Cs+ salts), with square antiprismatic coordination about Tl [5 carboxyl, 3 hydroxyl: Tl - O range 2.805(8)-3.188(8) angstrom]. The monohydrated silver hydrogen tartrate salt (3) is similar to but not isomorphous with Na+ (HC4H4O6)- . H2O, with the water and five tartrate oxygens coordinated [3 carboxyl, 2 hydroxyl: Ag - O range, 2.353(4) - 2.801(3) angstrom]. The stereo-chemistry about silver in (3) is distorted skew trapezoidal bipyramidal.