Ruthenium is a rare metal (less than 0.01 parts per million in the earth's crust). It is generally described as gray-white, hard and brittle. At room temperature it is resistant to virtually all acids. It's high melting point and brittle nature make casting difficult. Its chief commercial use is as a hardening agent in platinum jewelry.
History of Ruthenium
Element 44 (named from the Latin, ruthenia, for Russia) was originally discovered in 1807 by the Polish chemist Sniadecki, but the claim from a relative unknown was not accepted by a Paris commission and he withdrew it. It was not until 1828 that Gottfried Osann claimed to have found three new elements in his platinum samples that interest in the metal increased. Although the he could not substantiate the claim, he did not withdraw it. In 1844 Karl Klaus showed that two of Osann's metals were not new elements at all, but the third he was able to isolate and characterize.
Palladium is part of the the Platinum Group Metals (PGM) whic is located in the 5th and 6th rows of the transition metal section of the periodic table and includes Ruthenium, Rhodium, Palladium, Osmium, Iridium, and Platinum. Common characteristics include resistance to wear, oxidation, and corrosion, high melting points, and oxidation states of +2 to +4. They are generally non-toxic.
Applications of Ruthenium
Recently interest has grown in some compounds of ruthenium which possess the ability to convert visible light into a suitable energy source for splitting water into hydrogen and oxygen (for fuel). Work in this field is ongoing.
Stephen R. Marsden (ChemTopics)