The Re–Mo–S system: new data on phase relations between 400 and 1200 °C

Phase relations in the Re–Mo–S system were studied by the technique of evacuated silica tubes in the temperature range of 400–1200 °C. At 1000 °C, the following assemblages are stable: MoS₂ + ReS₂ + S₂(v); MoS₂ + ReS₂ + (Re,Mo)_ss + v; MoS₂ + Mo₂S₃ + (Re,Mo)_ss + v; Mo₂S₃ + χ + (Re,Mo)_ss + v, Mo₂S₃ + χ + (Mo,Re)_ss + v. Experiments aimed at the determination of the MoS₂-ReS₂ solid state solubility reveal an asymmetrical behaviour: molybdenite dissolves 2.7(9) wt% Re at 1000 °C, 2.6(4) wt% Re at 800 °C, and 2.2(6) wt% Re at 400 °C, whereas ReS₂ shows negligible Mo contents at all temperatures. The experimental solubility of ReS₂ in MoS₂ far exceeds Re contents in natural molybdenite, for which literature reports hundreds to thousands ppm.