Reed Relays and
Electronics India Limited
Manufacturer of Reed Switches, Reed Sensors and Reed-based products
Reed Relays and Electronics India Limited Incorporated in 1971


Ruthenium is a chemical element with the symbol Ru and atomic number 44. It is a hard silvery-white metal of the transition series. Because of its high melting point and excellent wear resistance, the use as plating or sputtering material in reed switches is preferred. Ruthenium coated Reed Switches perform as well as if not better than Rhodium, depending on the structure of the sputtering.

Ruthenium (Wikipedia)

Ruthenium is a chemical element with the symbol Ru and atomic number 44. It is a rare transition metal belonging to the platinum group of the periodic table. Like the other metals of the platinum group, ruthenium is inert to most other chemicals. Russian-born scientist of Baltic-German ancestry Karl Ernst Claus discovered the element in 1844 at Kazan State University and named ruthenium in honor of Russia. Ruthenium is usually found as a minor component of platinum ores; the annual production has risen from about 19 tonnes in 2009 to some 35.5 tonnes in 2017. Most ruthenium produced is used in wear-resistant electrical contacts and thick-film resistors. A minor application for ruthenium is in platinum alloys and as a chemistry catalyst. A new application of ruthenium is as the capping layer for extreme ultraviolet photomasks. Ruthenium is generally found in ores with the other platinum group metals in the Ural Mountains and in North and South America. Small but commercially important quantities are also found in pentlandite extracted from Sudbury, Ontario, and in pyroxenite deposits in South Africa.

Ruthenium, 44Ru
Pronunciation/rˈθniəm/ (roo-THEE-nee-əm)
Appearancesilvery white metallic
Standard atomic weight Ar°(Ru)
  • 101.07±0.02
  • 101.07±0.02 (abridged)
Ruthenium in the periodic table
Hydrogen Helium
Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon
Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon
Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon
Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon
Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson


Atomic number (Z)44
Groupgroup 8
Periodperiod 5
Block  d-block
Electron configuration[Kr] 4d7 5s1
Electrons per shell2, 8, 18, 15, 1
Physical properties
Phase at STPsolid
Melting point2607 K ​(2334 °C, ​4233 °F)
Boiling point4423 K ​(4150 °C, ​7502 °F)
Density (near r.t.)12.45 g/cm3
when liquid (at m.p.)10.65 g/cm3
Heat of fusion38.59 kJ/mol
Heat of vaporization619 kJ/mol
Molar heat capacity24.06 J/(mol·K)
Vapor pressure
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 2588 2811 3087 3424 3845 4388
Atomic properties
Oxidation states−4, −2, 0, +1, +2, +3, +4, +5, +6, +7, +8 (a mildly acidic oxide)
ElectronegativityPauling scale: 2.2
Ionization energies
  • 1st: 710.2 kJ/mol
  • 2nd: 1620 kJ/mol
  • 3rd: 2747 kJ/mol
Atomic radiusempirical: 134 pm
Covalent radius146±7 pm
Color lines in a spectral range
Spectral lines of ruthenium
Other properties
Natural occurrenceprimordial
Crystal structurehexagonal close-packed (hcp)
Hexagonal close packed crystal structure for ruthenium
Speed of sound thin rod5970 m/s (at 20 °C)
Thermal expansion6.4 µm/(m⋅K) (at 25 °C)
Thermal conductivity117 W/(m⋅K)
Electrical resistivity71 nΩ⋅m (at 0 °C)
Magnetic orderingparamagnetic
Molar magnetic susceptibility+39×10−6 cm3/mol (298 K)
Young's modulus447 GPa
Shear modulus173 GPa
Bulk modulus220 GPa
Poisson ratio0.30
Mohs hardness6.5
Brinell hardness2160 MPa
CAS Number7440-18-8
Namingafter Ruthenia, the 19th-century Latin name for Russia
Discovery and first isolationKarl Ernst Claus (1844)
Isotopes of ruthenium
Main isotopes Decay
abun­dance half-life (t1/2) mode pro­duct
96Ru 5.54% stable
97Ru synth 2.9 d ε 97Tc
98Ru 1.87% stable
99Ru 12.8% stable
100Ru 12.6% stable
101Ru 17.1% stable
102Ru 31.6% stable
103Ru synth 39.26 d β 103Rh
104Ru 18.6% stable
106Ru synth 373.59 d β 106Rh
 Category: Ruthenium
| references

« Back to Glossary Index