ptoxide

Ptoxide refers to platinum oxides, compounds of platinum with oxygen. The term often encompasses several discrete species, the most well-characterized being PtO (platinum(II) oxide), PtO2 (platinum(IV) oxide), and PtO3 (platinum(VI) oxide). Platinum is unusual among transition metals in forming stable high-oxidation-state oxides, and many platinum oxides are less stable than oxides of other metals.

Preparation and stability: PtO is typically prepared by controlled oxidation of platinum metal at relatively low temperatures or by chemical routes that transfer oxygen to Pt(0). PtO is thermally unstable and tends to decompose to Pt and O2 upon heating. PtO2 can be formed at higher oxidation pressures and temperatures; it too is unstable at ambient conditions and tends to decompose to PtO or to metallic Pt with release of oxygen. PtO3, corresponding to Pt(VI), has been reported only in specialized conditions and often as a transient or surface species rather than a bulk, stable solid. Many platinum oxides exist as non-stoichiometric phases or as surface species on metallic platinum, particularly under oxidizing catalytic environments.

Applications and occurrence: Platinum oxides are mainly of interest in surface and catalytic chemistry, where they can appear transiently on platinum electrodes and catalysts during oxidation or reduction cycles. They are not widely used as bulk materials due to their instability, but their formation and reduction are relevant to understanding platinum-catalyzed oxidation reactions.

See also: Platinum, Oxide, Oxidation states of platinum.