Tantalum tetrachloride

Tantalum Tetrachloride, TaCl4.—The formation of a green substance the composition of which agreed with that of a tetrachloride was observed during the preparation of the trichloride, but from the data available it was impossible to deeide if it was a simple compound or a mixture of the pentachloride and the trichloride.4... 

TaCI4 TANTALUM TETRACHLORIDE 1597 niCI4[g] THORIUM TETRACHLORIDE (GAS) 1646... 

TaCI4[g] TANTALUM TETRACHLORIDE (GAS) 1598 ThF2[g] THORIUM DIFLUORIDE (GAS) 1647... 

The performance of different types of chlorination processes is discussed comprehensively in overview [31]. It should be mentioned that carbon tetrachloride can also be applied successfully in the chlorination of rare refractory metal oxides, including tantalum oxide. 

Silver difluoride, 0014 Silver fluoride, 0013 Sodium chloride, 4036 Sodium iodide, 4623 Tantalum pentachloride, 4185 Tellurium tetrabromide, 0296 Thallium, 4922 Tin(II) chloride, 4116 Tin(IV) chloride, 4174 Tin(II) fluoride, 4331 Titanium(II) chloride, 4117 Titanium dibromide, 0284 Titanium diiodide, 4630 Titanium tetrachloride, 4176 Titanium tetraiodide, 4638 Titanium trichloride, 4158... 

The action of carbon tetrachloride or a mixture of chlorine with a hydrocarbon or carbon monoxide on the oxide.—H. N. Warren 9 obtained aluminium chloride by heating the oxide to redness with a mixture of petroleum vapour and hydrogen chloride or chlorine, naphthalene chloride or carbon tetrachloride was also used. The bromide was prepared in a similar manner. E. Demarpay used the vapour of carbon tetrachloride, the chlorides of chromium, titanium, niobium, tantalum, zirconium, cobalt, nickel, tungsten, and molybdenum H. Quantin, a mixture of carbon monoxide and chlorine and W. Heap and E. Newbery, carbonyl chloride. 

These are usually reactions of anhydrous transition and B metal halides with dry alkali metal salts such as the sulphides, nitrides, phosphides, arsenides etc. to give exchange of anions. They tend to be very exothermic with higher valence halides and are frequently initiated by mild warming or grinding. Metathesis is described as a controlled explosion. Mixtures considered in the specific reference above include lithium nitride with tantalum pentachloride, titanium tetrachloride and vanadium tetrachloride, also barium nitride with manganese II iodide, the last reaction photographically illustrated. 

Tantalum(V) bromide forms pale yellow, tabular crystals of specific gravity 4.67. It is extremely hygroscopic and is decomposed in cold or hot water. It dissolves with reaction in methanol and ethanol, with the evolution of heat, forming clear solutions which give no precipitate upon dilution with water.2 Its solubility in carbon tetrachloride is 0.3921 and 1.4651 g./lOO ml. of solution at 20° and 30°,... 

The form of molybdenum(IV) chloride obtained by the above method has been labeled the low-temperature a-isomer because of its structural similarity with the other tetrachlorides of tungsten, niobium, and tantalum and to distinguish it from the higher-temperature /8-isomer prepared from molybdenum(III) chloride and molybdenum(V) chloride. The /3-isomer may be obtained by heating the low-temperature form at 250°C. in a sealed tube with molybdenum(V) chloride for 24 hours. The excess molybdenum (V) chloride is sublimed away at 125°C. Because of its structural difference, the /S-isomer possesses a considerably higher paramagnetism and thermal stability than the a-isomer. 

Xenon difluoride reacts also with some halosubstituted alkanes18,19 at room temperature in chloroform, carbon tetrachloride, dichloromethane or bromoform, and depending on the nature of the solvent used chloro or bromo derivatives are isolated with imidazo-(l,2-fr)-pyridazine18. Carbon tetrachloride reacts with xenon difluoride at 180°C, while room-temperature transformations are achieved when various catalysts [antimony trifluoride, tantalum(V) fluoride or silica dioxide] are used, whose structure also influences the product distribution20. Tris(fluorosulfonyl)methane gives a fluoro-substi-tuted product in its reaction with xenon difluoride in difluorodichloromethane21. 

Oxidizer, Poison, Corrosive SAFETY PROFILE Poisonous and corrosive. Very reactive, a powerful oxidizer. Explosive or violent reaction with organic materials, water, acetone, ammonium halides, antimony, antimony trichloride oxide, arsenic, benzene, boron, bromine, carbon, carbon monoxide, carbon tetrachloride, carbon tetraiodide, chloromethane, cobalt, ether, halogens, iodine, powdered molybdenum, niobium, 2-pentanone, phosphoms, potassium hexachloroplatinate, pyridine, silicon, silicone grease, sulfur, tantalum, tin dichloride, titanium, toluene, vanadium, uranium, uranium hexafluoride. 

The method described above has been found suitable for the synthesis of Nb(NCSe)4(CioH8N2)2, Nb(NCS)4(dmbipy)2, and Nb(NCSe)4(dmbipy)2, where dmbipy is4,4 -dimethyl-2,2 -bipyridine. These niobium (IV) compounds can also be prepared from the hexakis(isothiocyanate)niobate(V) complex. The sensitivity of the materials to air and moisture makes the method somewhat more time-consuming, but the use of niobium tetrachloride as a starting material is avoided. The tantalum(V) complexes, Ta(NCS)6(CioH8N2)... 

This procedure has been used to prepare many other chlorides, e.g., tungsten hexachloride, vanadium tetrachloride, and the pentachlorides of niobium and tantalum. However, it is normally much easier to prepare chlorides than fluorides. This method will therefore find application only where this generalization is not applicable. In particular, it will find application where the chloride is thermally unstable under normal chlorination conditions and must be prepared at or below room temperature. This method has been used to advantage for the preparation of ReCle and the new compound osmium pentachloride. ... 

Even fewer complexes with nitrogen donor ligands have been reported and all are methyl cyanide adducts (Tables X and XI). Protactinium pentabromide forms a soluble 1 3 complex in contrast to the 1 1 complexes formed by niobium and tantalum pentahalides (46). Other actinide pentahalide-methyl cyanide complexes are still unknown. Protactinium tetrachloride, tetrabromide, and tetraiodide react with anhydrous, oxygen-free methyl cyanide to form slightly soluble 1 4 complexes (44, 48) which are isostructural with their actinide tetrahalide analogs. 

The bathophenanthroline method was used for determining iron in blood plasma [157], in plant materials [158], in waters [159], in niobium, tantalum, molybdenum, and tungsten [42,160], in molybdenum compounds [161], in cobalt [162], in cadmium and cadmium telluride [5], platinum [163], synthetic rubies and sapphires [164], silicon tetrachloride [165], and in boiler water [166]. 

TaCI3[g] TANTALUM TRICHLORIDE (GAS) 1597 fhCW THORIUM TETRACHLORIDE 1645... 

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