Tungsten general properties

He was the first to observe the very stable adsorbed monatomic hints on tungsten and platinum filaments, and was able, alter experiments with oil films on water, lo formulaic a general theory ol adsorbed films. He also studied the catalytic properties of such films. 

The carbides and nitrides of the early transition metals have attracted considerable attention. Much of this can be attributed to the catalytic properties of these materials. Levy and Boudart1 were the first to note the Pt-like catalytic behavior of WC, which for many reactions is more catalytically active than metallic tungsten.2 Others have noted that the early transition metal carbides and nitrides, in general, are excellent catalysts for reactions characteristic of the more expensive noble metals.3,4 For example, WC has been found to catalyze the isomerization of neopentane to isopentane,1 a reaction that previously had been known to be catalyzed only by iridium and platinum.5... 

Chemical analysis of the supported tungsten carbides allows quantification of the amount of carbidic and amorphous carbon,8 and in addition XPS measurements permit calculation of the carbide stoichiometry before and after FT reaction. This determination is not very accurate but it allows general trends to be discerned and correlations with catalytic properties. The bulk and surface compositions of supported tungsten carbides are shown in Table 18.3 in addition to their BET surface areas. 

In the sixth group, chromium, molybdenum, tungsten, and uranium constitute Family A. In their trioxides they show the characteristic valence of the sixth group and resemble in properties the non-metals of Family B, of which sulphur is the type. In their lower oxides they possess none of the characteristics of Group VI but show the general base-f orming properties of the heavy metals. 

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