Ruthenium
Symbol: Ru
Atomic Number: 44
Atomic Weight: 101.07
Uses: Ruthenium is one of the best hardeners for addition to palladium or platinum. It is alloyed with these metals to make electrical contacts with extreme wear resistance. One ruthenium-molybdenum alloy is superconductive at 10.6 K. Adding 0.1% ruthenium to titanium improves its corrosion resistance a factor of a hundred. Ruthenium oxides are versatile catalysts.
Sources: Ruthenium occurs with other members of the platium group of metals in the Ural mountains and in North and South America. It is also found in the Sudbury, Ontario nickel-mining region and in the pyroxinite deposits of South Africa. A complex process is used to isolate ruthenium. The final step is hydrogen reduction of ammonium ruthenium chloride to yields a powder that is consolidated by powder metallurgy or argon-arc welding.
Element Classification: Transition Metal
Discovery: Karl Klaus 1844 (Russia)
Density (g/cc): 12.41
Melting Point (K): 2583
Boiling Point (K): 4173
Appearance: silvery-gray, extremely brittle metal
Atomic Radius (pm): 134
Atomic Volume (cc/mol): 8.3
Covalent Radius (pm): 125
Ionic Radius: 67 (+4e)
Specific Heat (@20°C J/g mol): 0.238
Fusion Heat (kJ/mol): (25.5)
Pauling Negativity Number: 2.2
First Ionizing Energy (kJ/mol): 710.3
Oxidation States: 8, 6, 4, 3, 2, 0, -2
Electron Configuration: [Kr] 4d7 5s1
Lattice Structure: Hexagonal
Lattice Constant (Å): 2.700
Lattice C/A Ratio: 1.584
References: Los Alamos National Laboratory (2001), Crescent Chemical Company (2001), Lange's Handbook of Chemistry (1952), CRC Handbook of Chemistry & Physics (18th Ed.)
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