Preparation and X-Ray Study of Mixed-Anion Tungsten Dichalcogenides.

摘要

Mixed-anion systems of the tungsten dichalcogenides have been prepared by direct synthesis from the elements. X-ray investigations have been carried out as a function of composition. In the WS(2-x)SE(x) system, there is a continuous series of solid solutions, all having the 2H structure. The unit-cell parameters increase monotonically as x increases but there is a maximum in the c/a ratio at x = 1.3. In the WS(2-x)Te(x) system, monophasic regions occur for 0 < x < 0.62, where the structure is 2H, and 1.48 < x < or = 2.00 where the structure is that of WTe2. In the WS(2-x)Te(x) system, corresponding monophasic regions occur for 0 < x < 0.3 and 1.8 < x < or = 2.0.