Abstract:
Osmium (Os) is the seventh element in Group VIII in the periodic table. It has an atomic number of 76, an atomic weight of 190.2, and valences of 3, 4, and 6, and less commonly 1, 2, 5, 7, and 8. The average abundance of Os in the earth’s crust is probably <0.005 ppm, and in groundwaters it is <0.01 mg/L. Osmium occurs in iridosime and in platinum-bearing river sands. Osmium is used as a hardener with iridium and as a catalyst with platinum.
The aqueous chemistry is controlled by complex compounds, although the solubility in natural waters is relatively unknown. Analyze by flame atomic absorption methods (Sections 3111 D and E).