The volatility, toxicity, and complex isolation procedures of osmium make small scale laboratory isolations nearly impossible. The process of osmium isolation begins with treating the ore or byproduct that was formed from processing other metals in order to remove silver, palladium, platinum, and gold from the mixture. For this process, the residue is heated with sodium bisulphate until it melts. Water extractions yield a solution that contain rhodium sulfate; insoluble osmium residues are collected and then melted with sodium peroxide. Extraction of this solution in water yields osmium salts, iridium oxides, and ruthenium. Salt and chlorine gas treatments results in the formation of osmium oxides. These oxides are then dissolved through treatment with alcoholic sodium hydroxide to form a sodium hydroxide osmium complex. The complex is then treated with ammonium chloride to precipitate out the osmium chloride oxygen compound. Further evaporation and drying under hydrogen gas yields the pure osmium product.
