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| Atomic symbol: Ru |
| Atomic number: 44 |
| Atomic weight: 101.07 |
| Atomic volume: 8.3 cm3/mol |
| Density: 12.2 g/cm3 |
| Period Number: 5 |
| Group number: 8 |
| Group name: Trans. Met. |
| Element classification: Metal |
| Phase at room temperature: Solid |
| Melting Point: 2583.2 K |
| Boiling point: 4323 K |
| Heat of fusion: 24.0 kJ/mol |
| Heat of vaporization: 595.0 kJ/mol |
| Ionization Energy: 7.361 eV |
| 1st ionization energy: 711.1 kJ/mole |
| 2nd ionization energy: 1617.1 kJ/mole |
| 3rd ionization energy: 2746.9 kJ/mole |
| Electronegativity: 2.2 |
| Electron affinity: 101 kJ/mole |
| Specific heat: 0.238 J/gK |
| Heat atomization: 643 kJ/mole atoms |
| Shells: 2,8,18,15,1 |
| Electron Shell Configuration: [Kr] 4d7 5s1 |
| Minimum oxidation number: -2 |
| Maximum oxidation number: 8 |
| Minimum common oxidation number: 0 |
| Maximum common oxidation no: 4 |
Appearance & Characteristics |
| Structure:: hcp: hexagonal close pkd |
| Color: silvery-white |
| Hardness: 6.5 mohs |
| Toxicity: ? |
| Characteristics: hard |
| Uses: catalysts |
| Reaction with air: none below 800 deg.C |
| Reaction with 6M HCl: none |
| Reaction with 15M HNO3: none |
| Reaction with 6M NaOH: none |
| Number of isotopes: 7 |
| Oxide(s): RuO2 RuO4 |
| Hydride(s): none |
| Chloride(s): RuCl2 RuCl3 |
| Atomic Radius: 134 pm |
| Ionic radius (1- ion): pm |
| Ionic radius (1+ ion): pm |
| Ionic radius (2- ion): pm |
| Ionic radius (2+ ion): pm |
| Ionic radius (3+ ion): 82 pm |
| Thermal conductivity: 117 J/m-sec-deg |
| Electrical conductivity: 131.579 1/mohm-cm |
| Polarizability: 9.6 A^3 |
| Source: nickel ores (sulfides) |
| Relative abundance solar system: 0.270 log |
| Abundance earth's crust: -3 log |
| Estimated crustal abundance: 1×10-3 milligrams per kilogram |
| Estimated oceanic abundance: 7×10-7 milligrams per liter |
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| (L. Ruthenia: Russia) In 1827, Berzelius and Osann examined the residues left after dissolving crude platinum from the Ural mountains in aqua regia. While Berzelius found no unusual metals, Osann thought he found three new metals, one of which he named ruthenium. In 1844 Klaus, generally recognized as the discoverer, showed that Osann's ruthenium oxide was very impure and that it contained a new metal. Klaus obtained 6 g of ruthenium from the portion of crude platinum that is insoluble in aqua regia. |
| 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 in the Sudbury, Ontario nickel-mining region, and in the pyroxinite deposits of South Africa. |
| Ruthenium is a hard, white metal and has four crystal modifications. It does not tarnish at room temperatures, but oxidizes explosively. It is attacked by halogens, hydroxides, etc. Ruthenium can be plated by electrodeposition or by thermal decomposition methods. The metal is one of the most effective hardeners for platinum and palladium, and is alloyed with these metals to make electrical contacts for severe wear resistance. A ruthenium-molybdenum alloy is said to be superconductive at 10.6 K. The corrosion resistance of titanium is improved a hundredfold by addition of 0.1% ruthenium. It is a versatile catalyst. Hydrogen sulfide can be split catalytically by light using an aqueous suspension of CdS particles loaded with ruthenium dioxide. It is thought this may have application to removal of H2S from oil refining and other industrial processes. Compounds in at least eight oxidation states have been found, but of these, the +2, +3, and +4 states are the most common. Ruthenium tetroxide, like osmium tetroxide, is highly toxic. In addition, it may explode. Ruthenium compounds show a marked resemblance to those of cadmium. |
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