Tantalum -Tartaric acid

General methods for the preparation of niobium(v) and tantalum(v) complexes have been discussed and better synthetic routes to some known compounds have been described. [Nb(bpha) Cl], [Ta(bpha) Cl], and [NbO(t)3] (where bpha and t are the anions of benzoylphenylhydroxylamine and tropolone, respectively) have been prepared for the first time. NbClj or TaClj in methanol react with Hbpha to form the [M(bpha)4Cl] complexes. An aqueous solution of niobiumfv) which contains tartaric acid to prevent condensation of the hydrolysed metal species affords [NbO(t)3] with tropolone." " ... 

Instead of lixiviating with water, the pyrosulphate fusion is followed in a recent process 7 by extraction with tartaric acid solution the insoluble residue contains silica, tin, and lead, and the solution, after being saturated with hydrogen sulphide for the precipitation of copper, antimony, etc., contains the hydroxides of niobium and tantalum as well as tungsten, titanium, zirconium, rare earth metals, etc. 

Addition of ammonium hydroxide or ammonium sulphide to solutions of niobic acid and tantalic acid in mineral acids reprecipitates the niobic and tantalic acids, which may, however, retain some of the ammonia. This test does not distinguish between niobium and tantalum, and it does not proceed in the presence of tartaric acid. 

Niobium is kept in solution by the addition of tartaric acid, whose presence prevents the hydrolysis of tantalum and the consequent occlusion of niobium in the precipitate. 

Talspeak, 959 Talspeak process. 960 Tantalum complexes applications, 1014 Tartaric acid metal complexes geochemistry, 867 Tcchnatcs... 

Silica, If present, separates with the lead sulfate as does tungsten, niobium, tantalum, barlvun and less completely strontliim and calcium. Bismuth, antimony and silver contaminate the lead to some extent. The copreclpltatlon of antimony Is decreased by addition of tartaric acid. Addition of alcohol to the sulfate solution decreases the solubility of lead sulfate but Increases contamination by silver, bismuth or calcium. The normal separation based on the sulfate Involves dissolution of the lead sulfate In ammonium acetate solution. Hydroxide... 

Panda et al. prepared an aqueous solution precursor for a ferroelectric tantalum com-poimd, SrBi2Ta209 (Panda etal., 2003). This solution was synthesized using tantalum(V)-tartarate complex, which were prepared by slowly dissolving the hydrous tantalum(V) oxide in an aqueous solution of tartaric acid on heating. Into the aqueous solution of the tantalmn-tartarate complex, the other components (Sr-EDTA and Bi-triethanolamine) and an excess amoimt of triethanolamine were added. The resultant solution was red colored and homogeneous. The solution was dried and then calcined, crystallization occurring at 700°C. 

F. W. E. Strelow and T. N. van der Walt. Separation of lead from tin. antimony, niobium, tantalum, molybdenum and tungsten by cation exchange chromatography in tartaric-nitric acid mixtures. Anal Chem. 47,2272,1975. 

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