Molybdenum oxychlorides

Molybdenum pentachloride is used as a catalyst in chlorination reactions. It also is used in fire-retardant resins for soldering of flux for deposition of molybdenum coating and to prepare several other molybdenum compounds, including molybdenum oxychlorides and hexacarbonyl. 

Combination with bipyridyl hgand in carbon tetrachloride followed by hydrolysis yields a molybdenum oxychloride bipyridyl complex of formula MoOCR(bipy). When mixed with ammonium chloride in acetonitrile and water, an oxychloride-acetonitrile complex, NIRfMoOCRCHsCN], is obtained. 

A molybdenum oxychloride-based catalyst system, MoOCl4- -Bu4Sn-EtOH, is more active than Mods ones. " In the polymerization of 1-chloro-l-octyne by the oxychloride-based catalyst, propagation rate is improved to be faster and MWD of the formed polymer is smaller. This ternary catalyst also induces living polymerization of... 

Infrared spectral analysis9 is employed as a check for other impurities which might be present in the molybdenum(IV) chloride. Molybdenum oxychlorides can be easily identified by their characteristic absorptions in the 900-1000-em.-1 region, which is typical of Mo—O groups. In addition, an examination of the far infrared spectrum should show only the characteristic bands of molybdenum(IV) chloride at 404, 350, and 268 cm.-1. These can be distinguished from those of other molybdenum halide species. A test for the presence of molybdenum (III) chloride, which often occurs as a side product in other preparations of molybdenum(IV) chloride, is treatment with 6 N hydrochloric acid. Complete solubility indicates the absence of this chloride. 

Molybdenum hexafluoride, MoFj (mp 17 °C, bp 35 °C) [528], and molybdenum oxychloride, M0OCI3, which is prepared by the partial hydrolysis of molybdenum pentachloride [528], are suitable for the recovery of ketones from their dimethylhydrazones and tosylhydrazones under very mild conditions [525]. 

Molybdenum oxytetrachloride is a dark green crystalline compound with a melting point of 100 to 101°. Infrared absorption (KBr disk) has been used to establish the absence of OH- and H20 in verification of the anhydrous state. A broad band appears in the 970-em.-1 region and reveals molyb-denum-to-oxygen bonding. The oxychloride reacts with thoroughly dried Nujol so that satisfactory infrared spectra cannot be obtained with this as a dispersion medium. When exposed to light, molybdenum oxytetrachloride forms a brown film on the surface of the ampule. Since this film is not formed when the ampules are stored in the dark, molybdenum oxytetrachloride is concluded to be photosensitive. 

VI. Reactions of difluorodithiophosphinic acid with chlorides and oxychlorides of chromium, molybdenum and tungsten. Inorg. Chem. 11, 2011 (1972). 

Molybdenum(Vl) oxide behaves as a basic oxide in reactions with strong acids. Thus it forms an oxychloride, MoO(OH)2Cl2, with hydrochloric acid. Sulfuric acid forms an oxysulfate, M0O2SO4. 

Molybdenum pentachloride is hydrolyzed readily in water forming an oxychloride, M0OCI3. The reaction proceeds with hissing noise and evolution of heat. 

Molybdenum pentachloride forms mixed complexes and oxychloride adducts with several donors. Thus, the adducts with pyridine, bipyridyl and alkyl nitriles are MoCl4(py)2, MoCRObipy) and MoCR(RCN)2, respectively. 

Fill the apparatus with chlorine and perform chlorination of the molybdenum, heating the place of the tube where the metal is with the flame of a burner to 200-300 °C. What colour do molybdenum pentachloride and tungsten hexachloride have If oxychlorides are produced together with the molybdenum(V) or tungsten(VI) chlorides, distil them off in a chlorine stream. Transfer the product into a weighed test tube with a stopper, weigh it, and hand it in to your instructor. Calculate the yield in per cent. 

All operations must be performed in an inert atmosphere or in vacuo to prevent contamination by oxychlorides. The apparatus used for the preparation of molybdenum(IV) chloride consists of an all-Pyrex-glass vessel which can be attached to a standard vacuum line for easy manipulation of the reactants and products. This is shown in Fig. 17. 

Element 106. The chemical properties of element 106 (eka-tungsten) are predicted to be similar to those of tungsten, molybdenum and to some extent chromium, offering an even richer chemistry of complex ions than these elements. The hexafluoride should be quite volatile and the hexachloride, pentachloride and oxychloride should be moderately volatile. Penneman and Mann predict a -)-4 oxidation state in aqueous solution. Jprgensen s selection of k is for the hydrated cation and is not intended to account for the effects of complex ion formation. However, since tungsten is stabilized in the oxidation state of -t-6 by the tungstate ion, an analogous situation may be expected for element 106. 

Molybdenum dichloride, that is, the chloracid HMo3Cl,.4H20, dissolves in aqueous alkali hydroxides forming yellow solutions which, on boiling, deposit the black dihydroxide Mo(OH)2. The alcoholic solution conducts electricity, the molecular conductivity increasing on dilution hydrogen, the oxychloride Mo3Cl4(OH )2, and sometimes molybdenum are liberated at the cathode, w hilst acetaldehyde and ethyl chloride are formed at the anode. 

Molybdenum tetrachloride forms a semi-crystalline deliquescent powder, unstable in air, in which, if heated, it aelds the oxychloride MoOaCl and dichlormolybdic acid M0O3.2HCI it is also stated to be converted spontaneously into the pentachloride and trichloride. If sufficiently heated—though below 1380° C.—it is reduced to the metal. In water, alcohol, ether, and in dilute sulphuric acid it gives unstable solutions. 

The oxychloride MoO Clg is obtained when chlorides of molybdenum are heated in the air, and, among other compounds, when the dioxide, or a mixture of the trioxide with carbon, is heated in chlorine, or when molybdenum trioxide and phosphorus trichloride are heated together it is not formed, however, when a mixture of common salt, sulphuric acid, and molybdenum trioxide is heated cf. p. 28). A pale yellow amorphous substance, soluble in water and alcohol, it is easily sublimed, and is reduced on heating in hydrogen or carbon monoxide to the dioxide. 

The oxychloride MoOClj is formed on heating in chlorine a mixture of molybdenum pentachloride and the compound MoOgClj ... 

A number of elements form volatile chlorides that are partially or completely lost from hot hydrochloric acid solutions. Among these are the chlorides of tin(IV), germanium(IV), antimony(III), arsenic(III), and mercury(II). The oxychlorides of selenium and tellurium also volatilize to some extent from hot hydrochloric acid. The presence of chloride ion in hot concentrated sulfuric or perchloric acid solutions can cau.se volatilization losses of bismuth, manganese, molybdenum, thallium, vanadium, and chromium. 

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