Structures of racemic lithium tartrate hydrates

Racemic dimetal tartrate hydrates were obtained from the reaction of D,L-tartaric acid with LiOH and MOH, where M = Li, Na, K, Rb, Cs, NH4. Dilithium trihydrate Li-2(C4H4O6) center dot 3H(2)O (1) consists of two distinct two-dimensional coordination networks [Li-6(C4H4O6)(3)(H2O)(9)](n) (A) and [Li-2(C4H4O6)(H2O)(3)](2n) (B) which are arranged parallel in BAABAA fashion. Lithium sodium dihydrate LiNa(C4H4O6) center dot 2H(2)O (2) is as a three-dimensional coordination network in which discrete centrosymmetric [Li(C4H4O6)(H2O)](2) units are linked by NaO6 polyhedra. The monohydrates LiM(C4H4O6) center dot H2O with M = K (3), Rb (4), Cs (5) are three-dimensional coordination networks which are isostructural with the hydrogen-bonded ammonium analogue, M = NH4 (6). These structures are composed of [LiM(C4H4O6)(H2O)](n) layers linked by MO8 and MO10 polyhedra. Different patterns of hydrogen bonding between tartrate ions and water molecules are observed in structures 1, 2 and the series of 3-6