Group 8 Ruthenium

A member of the platinum group, ruthenium occurs native with other members of the group in ores found in the Ural mountains and in North and South America. It is also found along with other platinum metals in small but commercial quantities in pentlandite of the Sudbury, Ontario, nickel-mining region, and in pyroxinite deposits of South Africa. 

Titanium- and tungsten-based catalysts tend to react with olefinated ketones and esters, whereas molybdenum-based counterparts are more reactive toward olefins (though they can also react with aldehydes and other polar or protic groups). Ruthenium-based catalysts react preferentially with C=C double bonds over most other moieties, a feature that makes them unusually stable toward alcohols, amides, aldehydes, and carboxylic acids. Because of this trend, the functional-group tolerance of an olefin metathesis catalyst can be increased by focusing on a later class of transition metal such as ruthenium [8]. 

Although, as already mentioned, the iron II and III oxidation states are so dominant, we will nevertheless attempt to equally treat in this chapter, the electrochemistry of iron complexes in every documented oxidation state. Besides, despite the fact that iron will be considered almost exclusively, the redox chemistry of the other metals of the iron group, ruthenium and osmium, will also be discussed, together with its applications in bioelectrochemistry. 

With catalysts of the second group (ruthenium-rich) steady state is established more quickly - after 2-3 min (Fig. 3). The catalysts can be placed in the following order according to the time taken for establishment of steady state Pt > Pt - Ru > Ru — Pt. 

Platinum occurs native, accompanied by small quantities of iridium, osmium, palladium, ruthenium, and rhodium, all belonging to the same group of metals. These are found in the alluvial deposits of the Ural mountains, of Columbia, and of certain western American states. Sperrylite, occurring with the nickel-bearing deposits of Sudbury, Ontario, is the source of a considerable amount of metal. 

---