The syntheses of several ternary platinum oxides are reported. The Na and Cd bronzes Na x Pt 3 O 4 and Cd x Pt 3 O 4 as well as the bronze-like CaPt 2 O 4 were prepared in powder form under atmospheric pressure. The existence of Pt 3 O 4 is discussed. Syntheses for Cd x Pt 3 O 6 and a poorly defined new simple oxide of platinum with stoichiometry Pt 5 O 6 are given. The stability of these various oxides is discussed and their lattice parameters are given. The crystal chemistry of these oxides is systematized using stability fields for the platinum bronzes and for A 3 BX 4 compounds. The close structural relationship between the bronzes and Ag 3 PO 4 and Ag 3 AsO 4 is discussed. Photoelectron spectroscopic, magnetic susceptibility, and electrical conductivity data for the bronzes and various other platinum oxides are reported. From these data it is concluded that most bronzes are metallic oxides and a qualitative one-electron energy-band scheme is given explaining this metallic character. The nonexistence of CaPt 3 O 4 is discussed in terms of both this scheme and thermodynamics. The tendency of the bronzes to incorporate large quantities of foreign cations is explained in terms of the cage-like bronze structure.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Inorganic Chemistry