13451-11-1Relevant articles and documents
Preparation and crystal structure of new one-dimensional Ta selenide: [Ta(Se2)2]2TaBr6
Sokolov, Maxim,Imoto, Hideo,Saito, Taro,Fedorov, Vladimir
, p. 3735 - 3738 (1998)
Compound [Ta(Se2)2]2TaBr6 was prepared from elements by high temperature (450°C) stoichiometric reaction in high yield. The structure has been determined by single crystal X-ray diffraction. It contains infinite positively charged chains Ta(Se2)2. . . separated by octahedral TaBr6- anions. The slightly alternating Ta-Ta distances within the chains [3.182(2)-3.234(2) A] show a considerable degree of metal-metal interaction along the chain.
Synthesis and structure of Ta4S9Br8. An emergent family of early transition metal chalcogenide clusters
Sokolov, Maxim N.,Gushchin, Artem L.,Abramov, Pavel A.,Virovets, Alexandr V.,Peresypkina, Eugenia V.,Kozlova, Svetlana G.,Kolesov, Boris A.,Vicent, Cristian,Fedin, Vladimir P.
, p. 8756 - 8761 (2005)
Single crystals of Ta4S9Br8 are obtained by heating Ta, S, and Br2 at 400°C in a 4.0:9.0:4.0 molar ratio in a 44% yield. The structure was determined by X-ray analysis and consists of molecular clusters [Ta4(μ4-S)(μ-S2) 4Br8]. The tantalum atoms form a square with long Ta...Ta distances (3.30 A), with four S2 ligands bridging the Ta-Ta edges and one capping the square. Each Ta atom has two terminal bromine atoms. The compound is diamagnetic and has only two electrons for metal-metal bonding. IR and Raman spectral studies with the use of 34S allow to identify characteristic vibrations S-S (537 cm -1) and Ta4-μ4-S (407 cm-1). The compound is soluble in CH3CN, giving a dark-red solution with a characteristic electronic spectrum, which was assigned on the base of DFT calculations. ESI-MS spectra of the solutions show formation of {[Ta 4S9Br8]Br}- associates.
Krishnaswami, K. R.
, p. 845 (1928)
Chemistry of polynuclear metal halides. I. Preparation of the polynuclear tantalum halides Ta6X14
Kuhn, Phyllis J.,McCarley, Robert E.
, p. 1482 - 1486 (1965)
The anhydrous halides (Ta6X12)X2 (X = Br, I) have been produced in good yields by the reduction of the tantalum(V) halides with aluminum foil in a temperature gradient according to the reaction 18TaX5(g,l) + 16Al(s) = 3(Ta6X12)X2(s) + 16AlX3(g,l). Final products having atom ratios X/Ta smaller than the calculated 2.33 were shown to contain some tantalum metal. A lower tantalum chloride mixture was prepared by the same procedure, but evidence indicated the principal phase present was TaCl2.5 (Ta6Cl15). However, good yields of the ion Ta6Cl122+ could be obtained in solution from the anhydrous solids. Reflectance spectra of the anhydrous solids and absorption spectra of aqueous solutions were determined. The spectra were found to exhibit bands very characteristic of the Ta6X122+ structure.
Clark, R. J. H.,Kepert, D. L.,Lewis, J.,Nyholm, R. S.
, (1965)
Skinner, H. A.,Sutton, L. E.
, p. 668 - 680 (1940)
Reactivity of transition metal fluorides. III. Higher fluorides of vanadium, niobium, and tantalum
Canterford,O'Donnell
, p. 1442 - 1446 (2008/10/08)
A series of oxidation-reduction and halogen-exchange reactions has been used to compare the chemical reactivities of the pentafluorides of vanadium, niobium, and tantalum. Vanadium pentafluoride is extremely reactive and its reaction pattern with many reagents is extremely complex, depending largely on relative proportions of reagents and other experimental conditions. The pentafluorides of niobium and tantalum are very much less reactive than that of vanadium and are similar to each other. There is some evidence that of the two, the niobium compound is slightly more reactive. The reactivities of these three pentafluorides are discussed in terms of their physical properties and in relation to the higher fluorides of neighboring transition elements.
