| Symbol | Ru |
| Atomic number | 44 |
| Group | 8 (Iron group) |
| Period | 5 |
| Block | d |
| Classification | Transition Metal |
| Appearance | Silvery white metallic |
| Color | Silver |
| Number of protons | 44 p+ |
| Number of neutrons | 57 n0 |
| Number of electrons | 44 e- |
| Phase at STP | Solid |
| Density | 12.45 g/cm3 |
| Atomic weight | 101.072 u |
| Melting point | 2607 K 2333.85 °C 4232.93 °F |
| Boiling point | 4423 K 4149.85 °C 7501.73 °F |
| Heat of vaporization | 567.77 kJ/mol |
| Electronegativity (Pauling Scale) | 2.2 |
| Electron affinity | 100.96 kJ/mol |
| Oxidation states | −4, −2, 0, +1, +2, +3, +4, +5, +6, +7, +8 (a mildly acidic oxide) |
| Ionization energies |
|
| Discovery and first isolation | Karl Ernst Claus (1844) |
Discovery of ruthenium Though naturally occurring platinum alloys containing all six platinum-group metals were used for a long time by pre-Columbian Americans and known as a material to European chemists from the mid-16th century, not until the mid-18th century was platinum identified as a pure element. That natural platinum contained palladium, rhodium, osmium and iridium was discovered in the first decade of the 19th century. It is possible that the Polish chemist Jędrzej Śniadecki isolated element 44 (which he called "vestium" after the asteroid Vesta discovered shortly before) from South American platinum ores in 1807. He published an announcement of his discovery in 1808. His work was never confirmed, however, and he later withdrew his claim of discovery. Jöns Berzelius and Gottfried Osann nearly discovered ruthenium in 1827. They examined residues that were left after dissolving crude platinum from the Ural Mountains in aqua regia. Berzelius did not find any unusual metals, but Osann thought he found three new metals, which he called pluranium, ruthenium, and polinium. This discrepancy led to a long-standing controversy between Berzelius and Osann about the composition of the residues. As Osann was not able to repeat his isolation of ruthenium, he eventually relinquished his claims. In 1844, Karl Ernst Claus, a Russian scientist of Baltic German descent, showed that the compounds prepared by Gottfried Osann contained small amounts of ruthenium, which Claus had discovered the same year. Claus isolated ruthenium from the platinum residues of rouble production while he was working in Kazan University, Kazan. Choosing the name for the new element, Claus stated: "I named the new body, in honour of my Motherland, ruthenium. I had every right to call it by this name because Mr. Osann relinquished his ruthenium and the word does not yet exist in chemistry." In doing so, Claus started a trend that continues to this day - naming an element after a country. | |