Of tungsten compounds

Yous, B., Robin, S., Robin, J., and Donnadieu, A., Effects of Structure on the Optical Properties of Thin Films of Tungsten Compounds, Thin Solid Films, 130(3-7) 181-197 (Aug. 1985)... 

Wender and Hershkowitz [237] used the sensitivity of the recoil-free fraction in tungsten Mossbauer spectroscopy to deduce the effect of irradiation of tungsten compounds by Coulomb excitation of the resonance levels (2 states of I82,i84,i8 y with 6 MeV a-particles. While no effect of irradiation on the/-factors could be observed for tungsten metal in agreement with [233], a decrease of/was measured for WC, W2B, W2B5, and WO3 after irradiation. 

Fig. 7.51 Isomer shift versus formal electron configuration of tungsten compounds (from [226]). The triangles are data taken from [230], the circles from [226]...

Tungsten dust, powder, and fine particles will explode, sometimes spontaneously, in air. The dust of many of tungstens compounds is toxic if inhaled or ingested. 

The related family of tungsten compounds [W(t -H-SiR2CH2CH2PPh2)(CO)4] (44) was prepared analogously by a photochemical reaction of [W(CO)3] with HSiR2CH2CH2PPh2 ... 

By far the greatest number of tungsten compounds are those in which the element is hexavalent. These include all common halides except the iodide, i.e.. WF. WCl, as well as a number of oxvhalrdes, WOF4, WOCI4, WO Cl , WOBr4, and WO Br2, the Irioxide. trisullide, dibonde, and diphosphide already mentioned, various complexes and organometallic compounds, and the anions. 

The principal uses of tungsten compounds lie outside the scope of this chapter (e.g. catalysts for oil refining). WS2 is an effective additive for lubricating oils.41 CaW04 is used as a phosphor for X-ray screens.42 W03 is almost as effective as Mo03 as a flame retardant for poly(vinyl chloride).5... 

Reliable electrolytic methods for the analysis of tungsten compounds are not known. 

Figure 8.7. A selection of representative MAS NMR spectra of tungsten compounds, from Knight et al. (1986), by permission of the American Chemical Society.

Use Intermediate in preparation of tungsten compounds, (e.g., phosphotungstate), reagent, fireproofing fabrics and cellulose, alkaloid precipitant. 

A short, general discussion at the beginning emphasizes that the chemistry of tungsten compounds is rather complicated and complex. The following important facts must be taken into account. 

TABLE 4.1. Typical Examples of Tungsten Compounds for the Diiferent Valence States [4.1]. 

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