A New Perspective On Vanadyl Tartrate Dimers. Part Ii. Structure And Spectroscopic Properties Of Calcium Vanadyl Tartrate Tetrahydrate

The calcium vanadyl tartrate complex [Ca(VO)(d,/-C₄H₂O₆)(H₂O)₄] has been synthesized and characterized by spectroscopic methods. Its crystal structure was solved by X-ray methods. The compound is monoclinic, space group P2₁/c, with a = 8.0282(5), b= 17.1568(8), c= 7.6113(3) A, β= 94.269(4)° and Z = 4. The structure consists of centrosymmetric vanadyl tartrate dimers, [(VO)(d,/-C₄H₂O₆)]₂^4-, and calcium cations placed between them. As a result, dimers form chains in the [101] direction. Neighbouring chains are linked by the coordination of the calcium ion to the oxygen atom of a vanadyl group of a different chain, thus forming a two-dimensional structure. Different layers are linked by hydrogen bonds. Spectroscopic studies show the existence of intra-dimeric interactions between vanadium atoms.