Tungsten and Sulfur

PR Direct synthesis of W and S at 800-900 °C in pure nitrogen atmosphere (P-WS2). Sulfur vapor over WO3 at 1400 °C 2WO3 + 4S 2WS2 + 3O2 (a-WSj). Thermal decomposition of WS3. 

WS2 has a layer structure, each metal atom being surrounded by a trigonal, prismatic array of S atoms WS2 is a diamagnetic semiconductor. 

It is insoluble in water, diluted nitric and sulfuric acid. It dissolves in HF-aqua regia mixture, molten alkalis, and alkali carbonates. It decomposes by heating in air, but its thermal stability is 90 C higher than that of M0S2. 

FIGURE 4.15. Inteigrowth tungsten bronze structure of the pyrochlore type (double tunnel) [4.30]. 

A Forms adherent, soft, continuous films on different surfaces and exhibits good 

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