A method is described for the preparation of chalcogenides of ruthenium, rhodium, osmium and iridium transition metals of the Periodic Table of the Elements which comprises mixing in the absence of an aqueous solvent a Group VIII transition metal salt with a source of chalcogenide, said chalcogenide being selected from the group consisting of sulfur, selenium, tellurium and mixtures thereof, yielding a precipitate of the formula MX.sub.y wherein M is selected from the group consisting of ruthenium, rhodium, osmium and iridium, X is sulfur, selenium, tellurium and mixtures thereof and y is a number ranging from about 0.1 to about 3, preferably 0.1 to about 2.5. By the practice of the nonaqueous synthesis technique, Group VIII chalcogenides are prepared which are finely divided, have a high surface area, small particle size and small crystallite size which are also free of excess sulfur, water and/or hydrolysis products. Layered stoichiometric osmium disulfide is prepared by this technique. The precipitates may be cleansed of any anion salt coproduct by any technique common to the art.
Compounds of the formula MX.sub.y thus prepared are superior sulfur-tolerant catalysts in catalytic processes, for example, hydrodesulfurization, hydrodenitrogenation, hydroconversion, hydrogenation.