Magnetic and other studies of ruthenium dioxide and its hydrate

The magnetic behaviour of ruthenium dioxide up to 1000°K is interpreted in terms of J being ca.– 3000 cm.–1 in dioxo-bridged chains of ruthenium atoms. The high electrical conductivity as well as certain structural features imply that the average oxidation state of the ruthenium atoms is substantially greater than +4.The oxide hydrate has a high surface area; it is formulated as RuO2 +x, yH2O since there can be an excess (chemisorbed) of oxygen particularly after removal of some of the water. Values of x up to 0·12 have been found whereas y is often 1 to 1·3. The susceptibility, though generally similar to that of RuO2, varies from sample to sample: its behaviour is discussed in relation both to the influence of adsorbed groups and also to some terminal ruthenium atoms behaving as mononuclear Ru(V), i.e., being in the d3 state. Expected spectral bands in the infrared have not been detected owing to the presence of electronic conductance bands.