Sodium Osmyl Oxynitrite, Na₂(OsO₃)(NO₂)₂

Sodium Osmyl Oxynitrite, Na₂(OsO₃)(NO₂)₂, is apparently formed by the action of sodium nitrite on osmium tetroxide. It has not been isolated from the resulting solution, as evaporation yields merely a syrupy liquid. Addition of ammonium chloride to the solution changes its colour from deep brown to yellow, and a yellow crystalline powder, namely, Ammonium Osmyl Oxynitrite, (NH₄)₂OsO₃.(NO₂)₂, is deposited.

The corresponding silver, barium, and strontium salts have been prepared, crystallising with one, four, and three molecules of water respectively. The osmyl oxy oxalates of potassium and ammonium have also been prepared.