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Element Fact
Americium is one of the few radioactive elements that find its use in homes as a smoke detector.

Ruthenium, Ru

ruthenium sample

Atomic number: 44
Atomic mass: 101.07(2)
Natural abundance: 0.0001 ppm
96Ru (95.907598) -5.52%
98Ru (97.905287) - 1.88%
99Ru (98.905939) - 12.7%
100Ru (99.904220) - 12.6%
101Ru (100.905582) - 17.0%
102Ru (101.904350) - 31.6%
104Ru (103.905430) - 18.7%

History and Production

From Latin Ruthenia, meaning Russia. It was discovered in the residues left after crude platinum has been dissolved in aqua regia by K. Klaus in 1844. The metal is obtained commercially from the 'platinum concentrates' which are commonly obtained as anode slimes in the electrolytic refinement of nickel. The extraction involves a series of complex chemical treatments and the final product is obtained in powder form. It is used to harden platinum and palladium to make wear-resistant electrical contacts. The corrosion resistance of titanium is also improved significantly by adding a minute amount of ruthenium. It is also used as a catalyst in hydrogenation process.

Physical Data

The metal is white, hard and does not tarnish in room temperature. It is resistant to attack by acids or aqua regia. Ruthenium is very rare in crustal rocks, it is usually found in metallic elemental state along with other platinum metals.

Interatomic distance: 265 pm
Melting point: 2334C
Boiling point: 4150C
Thermal conductivity/Wm-1K-1: 117 (27C)
Density/kgm-3: 12370 (20C), 10900 (m.p.)

Standard Thermodynamic Data (atomic gas)

Enthalpy of formation: 642.7 kJ/mol
Gibbs free energy of formation: 595.8 kJ/mol
Entropy: 186.5 J/mol K
Heat capacity: 21.5 J/mol K

Electronic data

Electronic configuration: [Kr] 4d7 5s1
Term symbol: 5F5
Electron affinity: 101.3097 kJ/mol   Electronegativity (Pauline): 2.20
Ionization energy (first, second, third): 710.181, 1617.10, 2746.94 kJ/mol

Chemical properties

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