Molybdenum tribromide

Molybdenum hexafluoride. 3,1412 Molybdenum-iron-sulfur complexes, 4,241 Molybdenum oxide amino acid formation prebiotic systems, 6, 872 Molybdenum storage protein microorganisms, 6, 681 Molybdenum telluride, 3, 1431 Molybdenum tetraalkoxides physical properties, 2, 347 Molybdenum tribromide, 3,1330 Molybdenum trichloride, 3,1330 Molybdenum trifluoride, 3, 1330 Molybdenum trihalides, 3, 1330 bond lengths, 3, 1330 magnetic moments, 3,1330 preparation, 3,1330 properties, 3, 1330 structure, 3,1330 Molybdenum triiodide, 3,1330 Molybdenum trioxide complexes, 3, 1379 Molybdenum triselenide, 3, 143)... 

Two other bromides are also obtained from the elements. These are molybdenum tribromide, MoBrs, and molybdenum tetrabromide, MoBr4. MoBrs, a black sobd, is obtained by heating the elements at 350 to 400°C. 

Molybdenum Tribromide, MoBrj, is formed w hen bromine-vapour is passed over moderately heated molybdenum or over a mixture of the dioxide with carbon. The compound sublimes, recondensing to dark green erj stals, which tend on heating to decompose into bromine and the dibromide, and which are insoluble in water, dilute acids, or alkalies they dissolve, however, in concentrated alkalies, the bromide undergoing hydrolysis. ... 

Molybdenum(III) complexes include the molybdenum trihaUdes. Molybdenum trichoride [13478-18-7], trifluoride [20193-58-2], tribromide [13446-57-6], and ttiiodide [14055-75-5] are all known. The oxide dimolybdenum trioxide [1313-29-7], M02O2, and the seldom-studied sulfide analogue [12033-33-9], M02S2, are formally trivalent. 

Under the conditions described above, the formation and extraction of molybdenum (IV) bromide proceed at the rate of ca. 0.086 g. hour-1 or 2.1 g. day-1. For example, 6.85 g. of the tribromide afforded 7.53 g. of tetrabromide after an extraction... 

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). 

Molybdenum Dibromide, MoBtj, is obtained by heating the tribromide, or by strongly heating the metal in bromine vapour. It is a reddish-yellow substance, stable in air, insoluble in water and in acids in dilute alkalies it is soluble with formation of a hydrate, but by concentrated alkalies it is decomposed. For reasons similar to those applying in the case of the chloride (see p. 123), the formula of the bromide is considered to be (MojBr4)Br2. ... 

Molybdenum Tetrabromide, MoBr4.—During the preparation of the tribromide, a certain quantity not only of oxybromides q.v.) but also of the tetrabromide is formed, the latter forming black fusible needles soluble in water and hydrolysed by alkalies. ... 

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