[en] Photometric methods for determination of zirconium, niobium and tantalum in bla algae. Algae ash has been subjected to analysis. Zirconium has been determined by formation of colored complex with arsenazo 3, niobium - by reaction with orthonitrophenylfluoron. Separation from interfering elements has been performed by coprecipitation on Fe(OH)₃ and subsequent extraction by chloroform solution of tribenzylamine. Tantalum has been separated by extraction of its fluoride complex from sulphate fluoride medium by the mixture of acetone with isobutanol in presence of ammonium sulfate. Tantalum has been determined in the form of sahcylfluoron in presence of ammonium oxalate Zr content in the algae ash by order corresponds to its content in the plankton ash

[en] Works on analytical chemistry of tantalum published in 1970-1988 have been systematized and generalized. Attention is concentrated on the recent achievements in the field of chemical, physicochemical and physical (including neutron-activation) methods of tantalum determination. Spectrophotometric and atomic-emission methods of tantalum determination, especially in the presence of niobium, have been considered in greater detail

[en] Dibromogallein is obtained - a new organic reagent of the trioxyfluorone series: 2,7 dibrom - 3,4,5 trioxy-9-(2'-carboxy-phenyl)-6-fluorone. Its spectral, acid-alcaline complexing, and analytical properties are studied. The reaction of gallein and dibromogallein with a number of ions of 3-4 group metals is investigated. The improvement is noted in analytical properties of metal complexes with gallein and dibromogallein in the presence of long-chain quaternary ammonium bases. Shown are analytical advantages of the new reagent as compared with gallein, and prospects of using dibromgallein in the photometric determination of molybdenum, tungsten, niobium, and tantalum

[en] A new analytical form for non-extraction photometric determination of Ta microamounts in the presence of niobium is obtained. For the purpose Ta interaction with salicylfluorone (2-hydroxyphenylfluorone, SF) in citratesulphuric acid mediUm in the presence of surfactants is studied. Formation conditions and spectrophotometric characteristics of Ta complex with SF in the presence of gelatin, cetylpyridinium, syntanol and triton, X-100 are presented. It is established that in the system with syntanol H₂O₂ introduction results in efficient disguising of niobium, which is more considerable in acid medium (pH 1.3-1.5). When H₂SO₄ content is 0.4-0.5 mol/l, sodium citrate - 1.2-1.6%, H₂O₂ - 0.01-0.02%, syntanol (triton X-100) and 0.01-0.02% H₂O₂ up to 5 mg of niobium do not interfere with the determination of 1-5 μg Ta. In the process of tantalum determination the presence of 1-2 mg of Zr, Hf, Al is admissible. Interfering effect of 30 μg of Sn(4) and 50 μg of Ti (4) can be eliminated by means of introduction of 1x10^-2 M EDTA into solution. Techniques of tantalum, impurities determination in metal Nb and Nb₂O₅ are developed

[en] Technique for determination of zirconium microimpurity in gallium gadolinium garnet was developed. Lithium methaborate was used for garnet decomposition, then gallium was separated by extraction with diethyl ether from hydrochloric acid solution zirconium was extracted during 15 min with isoamyl alcohol in the form of a complex with morin and determined by photometry. The developed technique enables to determine up to 0.5 μg Zr in 1 g of garnet. The period of sample analysis together with decomposition equals 2.5 to 3 h

[en] It has been carried out the investigation of the mosaic structure of ZnO crystals by two methods providing the information on mosaic structure and inner stresses (γ-ray diffraction and conoscopic method). It has been observed a certain correlation between the results obtained by the two methods. (author)