The first dinuclear nonperoxido tartrato complexes of vanadium(V), (NMe4)(2)[V2O4((2R,3R)-H(2)tart)(2)]center dot 6H(2)O (1), (NMe4)(2)[V2O2((2R,3R)-tart)((2S,3S)-tart)] (2), (NEt4)(2)[V2O2((2R,3R)-tart)((2S,3S)-tart)] (3) (tart = tartrato(4-) = C4H2O64-) have been prepared from water-ethanol medium and characterized by X-ray structure analysis and spectral methods. The formation of the complexes has been found to be stereospecific; the composition and structure of anions containing one or both enantiomers of the ligand are profoundly different. The structure of anions in 1-3 also differs significantly from the structure of other dinuclear vanadium(V) alpha-hydroxycarboxylato complexes, but, interestingly, the geometry of the [V2O2((2R,3R)-tart)((2S,3S)-tart)](2-) ion resembles the structure of the [(VO)(2)((2R,3R)-tart)((2S,3S)-tart)](4-) ion which has a vanadium(IV) center. Using Raman and V-51 NMR spectroscopy the solvent dependent mutual transformations of [V4O8((2R,3R)-tart)(2)](4-) (V4L2-RR), [V4O8((2S,3S)-tart)(2)](4-) (V4L2-SS), [V2O4((2R,3R)-H(2)tart)(2)](2-) (V2L2-RR), [V2O4((2S,3S)-H(2)tart)(2)](2-) (V2L2-SS), and [V2O2((2R,3R)-tart)((2S,3S)-tart)](2-) (V2L2-rac) have been established. In aqueous solution the following reactions take place; 2 V2L2-rac -> V2L2-RR + V2L2-SS followed by partial decomposition, V2L2-RR -> V4L2-RR + 2L (V2L2-SS -> V4L2-SS + 2L). On the other hand V2L2-rac is stable in CH3CN solution while V2L2-RR (V2L2-SS) decomposes into several species.