Tungsten tribromide

Tungsten tribromide [15163-24-3] WBr, prepared by the action of bromine on WBr2, in a sealed tube at 50°C (17), is a thermally unstable black powder that is insoluble in water. 

The boron so obtained is an amorphous powder. It can be obtained in the crystalline state by reducing the vapour of boron tribromide with hydrogen, either in an electric arc or in contact with an electrically-heated tungsten filament ... 

Undoubtedly, the best method for the production of pure anhydrous lanthanide trihalides involves direct reaction of the elements. However, suitable reaction vessels, of molybdenum, tungsten, or tantalum, have to be employed silica containers result in oxohalides (27). Trichlorides have been produced by reacting metal with chlorine (28), methyl chloride (28), or hydrogen chloride (28-31). Of the tribromides, only that of scandium has been prepared by direct reaction with bromine (32). The triiodides have been prepared by reacting the metal with iodine (27, 29, 31, 33-41) or with ammonium iodide (42). 

Acrylic acid, Initiator, Water, 1148 Aluminium chloride, Water, 0062 Barium peroxide, Propane, 0216 1,3-Benzodithiolium perchlorate, 2677 1,1 -Bis(fluorooxy)tetrafluoroethane, 0641 Borane-tetrahydrofuran, 0138 Boron tribromide, Water, 0122 Bromine, Aluminium, Dichloromethane, 0261 Bromine, Tungsten, Tungsten trioxide, 0261 f 1,3-Butadiene, 1480 Calcium oxide, Water, 3937 Chlorine trifluoride, Refractory materials, 3981 Chromium trioxide, Acetic acid, 4242 Copper(II) oxide, Boron, 4281 Diazoacetonitrile, 0675 Dihydroxymaleic acid, 1447 Ethyl azide, 0872... 

Following this chemical transport, the tube is immediately placed in a temperature gradient of 250°C./room temperature in order to vaporize the more volatile species, W02 Br2, WOBr4, WBr6. The yield is approximately 13 g. of pure tungsten(V) tribromide oxide (98%). Anal. Calcd. for WOBr3 W, 41.83 Br, 54.53 O, 3.64. Found W, 42.03 Br. 54.56 O, 3.39. 

Differential thermal analysis has shown that tungsten(V) tribromide oxide decomposes above 420°C. without melting. The density, determined pycnometrically, is 5.87 g./cc. 

See Boron tribromide Tungsten trioxide See related METAL HALIDES... 

It was also of interest to us how changes in the organic residue of the carbyne ligand influence the stability and the behavior of carbyne complexes. Hence, we treated with boron tribromide a series of pentacarbonyl-[methoxy (aryl) carbene tungsten (0) complexes which were substituted at... 

The synthesis of cyclopropyl carbyne complexes follows the general Fischer synthesis of carbyne complexes from alkoxycarbene complexes typical of transition metals of group 6 (Cr, Mo, W). Thus, addition of cyclopropyllithium to chromium and tungsten hexacar-bonyl followed by alkylation of the acylmetallate intermediate with triethyloxonium fluo-roborate gave cyclopropyl ethoxycarbene complexes which, upon subsequent reaction with boron tribromide at -25 °C, afforded the corresponding /ra 5 -bromotetracarbonyl cyclopropylcarbyne complexes (equation 91). However, whereas the monotungsten... 

Deposition Utilizing Alternating Current. Hydrogen and boron tribromide vapors were used to obtain a coating of boron on 1-mil tungsten wire in a corona developed with 60-c.p.s. alternating current. At... 

Deposition on 0.5-mil Tungsten Wire. The corona was maintained continuously in Runs 30-1 and 30-2. The power input was discontinued in all remaining runs until the boron tribromide and the cell had attained the desired temperature. The currents and voltages indicated for all runs below 35 are approximate since no adjustments were made once the run had begun. 

The effects of operating conditions are similar to those observed for deposition on 1.0-mil tungsten wire. However, the decreased heating effects of the 0.5-mil wire necessitated heating the cell to about 200°C. to prevent condensation of the boron tribromide. 

U0Br3 URANIUM TRIBROMIDE OXIDE 1749 W(CO)6 TUNGSTEN HEXACARBONYL 1789... 

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