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. This technique also permits the preparation of a heretofore unobtainable composition, layered stoichiometric osmium disulfide. The precipitates which result as a consequence of the instant process may be cleansed of any anion salt coproduct by any technique common to the art, pumping under vacuum being one such technique, washing with a suitable solvent being another.Compounds of the formula MX.sub.y wherein M, X and y are as defined above, prepared by the low temperature, nonaqueous precipitation technique herein disclosed are superior sulfur-tolerant catalysts in catalytic processes, for example, hydrodesulfurization, hydrodenitrogenation, hydroconversion, hydrogenation.