Chemical Properties
Osmium (IV) oxide is a dark bluish black powder(s), with rutile crystal(s) form [KIR82] [ALD94]. Insoluble in water and acids. Forms OsO4 on heating in air; readily reduced to the metal by H2.
Uses
The osmium oxide/hexacyanoruthenate films modified electrodes plays an important role for the electrocatalytic reaction of catecholamines and sulfur oxoanions. Used as catalyst. Metallic osmium or an osmium oxide-ruthenium cyanide film modified graphite electrodes plays an essential role for the determination of biogenic amines from electrocatalytic responses.
Preparation
Osmium (VIII) oxide is reduced in the cold by a stream of H2. If, however, the OsO4 is heated in the H2 stream, the product is the metal. Osmium (IV) oxide can also be prepared by heating a fine powder consisting of a mixture of K2OsCl3 and three times its amount of Na2C03. The temperature should be lower than red heat; the cooled product is extracted with water which is slightly acidified with dilute hydrochloric acid. The product is perfectly pure OsO2.
Safety Profile
Brown or black crystals. Amorphous form can explode spontaneously in air. When heated to decomposition it emits toxic fumes of Os.
Structure and conformation
Crystal structure of Osmium (IV) oxide: rutile type.
