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About Ruthenium

Ruthenium Bohr

Ruthenium was discovered in 1844 by Karl Ernst Claus and named for Ruthenia, the Latin word for Claus’s native Rus. It was the last member of the platinum group of elements to be officially discovered, and like other members of that family is notable for being hard and corrosion resistant. In fact, ruthenium is harder than both platinum and palladium, and like the more expensive rhodium can be used to harden alloys of those elements. Thin-coatings of platinum-ruthenium and palladium-ruthenium alloys are often used to make electrical contacts wear-resistant. Additionally, ruthenium is added to titanium to impart corrosion resistance and used in high-temperature single-crystal superalloys used most commonly in aerospace applications. Ruthenium is also compatible with vapor deposition for producing thin films as well for use in other semiconductor processing techniques, and is under investigation for use in microelectronics.

In addition to the roles it plays in its metallic form, ruthenium finds many applications in the form of its compounds. Ruthenium dioxide and organometallic ruthenium complexes are used as catalysts in research, in organic and pharmaceutical chemistry, and in industrial settings. Ruthenium-based dyes have applications as biological stains in for light and electron microscopy, and are used in some dye-sensitized solar cells. The oils in fingerprints react with ruthenium tetroxide to produce darkly colored ruthenium dioxide, a process that is used to expose latent prints.

Finally, there are a few uses for ruthenium in medical applications. A radioactive isotope of ruthenium is used in radiotherapy of eye tumors, and several ruthenium-centered complexes are under investigation for anticancer properties.

Like other platinum group metals, ruthenium is typically obtained for commercial use as a byproduct from nickel and copper mining and processing, but can also be obtained from ores rich in platinum and from alluvial deposits. Along with rhodium and palladium, ruthenium is a decomposition product of uranium and could theoretically be recovered from spent nuclear fuel, but the problems inherent in working with radioactive materials make this an impractical source for the rare element.

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Ruthenium is primarily used for wear-resistant electrical contacts and the production of thick-film resistors. Ruthenium is one of the most effective hardeners for platinum and palladium and is alloyed with these metals to make electrical contacts for extremely wear resistant electronics and laboratory equipment. The corrosion resistance of titanium is improved a hundredfold by the addition of 0.1% ruthenium. Ruthenium is also a versatile catalyst. Hydrogen sulfide can be split catalytically by light using an aqueous suspension of cadmium sulfide particles loaded with ruthenium dioxide. Ruthenium is available as metal and compounds with purities from 99% to 99.999% (ACS grade to ultra-high purity). High Purity (99.999%) Ruthenium (Ru) Sputtering TargetHigh Purity (99.999%) Ruthenium Oxide (RuO2·xH2O)PowderElemental or metallic forms include pellets, rod, wire and granules for evaporation source material purposes. Ruthenium nanoparticles and nanopowders provide ultra-high surface area. Ruthenium oxides are available in powder and dense pellet form for such uses as optical coating and thin film applications. Oxides tend to be insoluble. Fluorides are another insoluble form for uses in which oxygen is undesirable such as metallurgy, chemical and physical vapor deposition and in some optical coatings. Ruthenium is also available in soluble forms including chlorides, nitrates and acetates. These compounds can be manufactured as solutions at specified stoichiometries.

Ruthenium Properties

Ruthenium(Ru) atomic and molecular weight, atomic number and elemental symbolRuthenium is a Block D, Group 8, Period 5 element. Ruthenium Bohr ModelThe number of electrons in each of ruthenium's shells is 2, 8, 18, 15, 1 and its electron configuration is [Kr] 4d7 5s1. The ruthenium atom has a radius of and its Van der Waals radius is In its elemental form, CAS 7440-18-8, ruthenium has a silvery white metallic appearance. Elemental RutheniumRuthenium is a rare transition metal belonging to the platinum group of metals. It is found in pentlandite, pyroxenite, and platinum group metal ores. Ruthenium was first discovered by Karl Klaus in 1844. The name Ruthenium, originates from the Latin word 'Ruthenia' meaning Russia.

Symbol: Ru
Atomic Number: 44
Atomic Weight: 101.07
Element Category: transition metal
Group, Period, Block: 8, 5, d
Color: silvery white metallic/ silvery-white
Other Names: Ruthénium, Rutenio, Rutênio
Melting Point: 2334°C, 4233 °F, 2607 K
Boiling Point: 4150 °C, 7502 °F, 4423 K
Density: 12.45 g·cm3 (estimated)
Liquid Density @ Melting Point: 10.65 g·cm3
Density @ 20°C: 12.2 g/cm3
Density of Solid: 12370 kg·m3
Specific Heat: 0.24 (kJ/kg K)
Superconductivity Temperature:  0.49 [or -272.66 °C (-458.79 °F)] K
Triple Point: N/A
Critical Point: N/A
Heat of Fusion (kJ·mol-1): 23.7
Heat of Vaporization (kJ·mol-1): 567
Heat of Atomization (kJ·mol-1): 641.031
Thermal Conductivity: 117 W·m-1·K-1
Thermal Expansion: (25 °C) 6.4 µm/(m·K)
Electrical Resistivity: (0 °C) 71 nΩ·m
Tensile Strength: N/A
Molar Heat Capacity: 24.06 J·mol-1·K-1
Young's Modulus: 447 GPa
Shear Modulus: 173 GPa
Bulk Modulus: 220 GPa
Poisson Ratio: 0.3
Mohs Hardness: 6.5
Vickers Hardness: N/A
Brinell Hardness: 2160 MPa
Speed of Sound: (20 °C) 5970 m·s-1
Pauling Electronegativity: 2.2
Sanderson Electronegativity: N/A
Allred Rochow Electronegativity: 1.42
Mulliken-Jaffe Electronegativity: N/A
Allen Electronegativity: N/A
Pauling Electropositivity: 1.8
Reflectivity (%): N/A
Refractive Index: N/A
Electrons: 44
Protons: 44
Neutrons: 57
Electron Configuration: [Kr] 4d7 5s1
Atomic Radius: 134 pm
Atomic Radius,
non-bonded (Å):
Covalent Radius: 146±7 pm
Covalent Radius (Å): 1.36
Van der Waals Radius: N/A
Oxidation States: 8, 7, 6, 4, 3, 2, 1, -2 (mildly acidic oxide)
Phase: Solid
Crystal Structure: hexagonal close-packed
Magnetic Ordering: paramagnetic
Electron Affinity (kJ·mol-1) 101.274
1st Ionization Energy: 710.19 kJ·mol-1
2nd Ionization Energy: 1617.11 kJ·mol-1
3rd Ionization Energy: 2746.96 kJ·mol-1
CAS Number: 7440-18-8
EC Number: 231-127-1
MDL Number: MFCD00011207
Beilstein Number: N/A
SMILES Identifier: [Ru]
InChI Identifier: InChI=1S/Ru
PubChem CID: 23950
ChemSpider ID: 22390
Earth - Total: 1.18 ppm
Mercury - Total: 0.91 ppm
Venus - Total: 1.23 ppm
Earth - Seawater (Oceans), ppb by weight: 0.0007
Earth - Seawater (Oceans), ppb by atoms: 0.000043
Earth -  Crust (Crustal Rocks), ppb by weight: 1.0
Earth -  Crust (Crustal Rocks), ppb by atoms: 0.2
Sun - Total, ppb by weight: 5.0
Sun - Total, ppb by atoms: 0.06
Stream, ppb by weight: N/A
Stream, ppb by atoms: N/A
Meterorite (Carbonaceous), ppb by weight: 830
Meterorite (Carbonaceous), ppb by atoms: 160
Typical Human Body, ppb by weight: N/A
Typical Human Body, ppb by atom: N/A
Universe, ppb by weight: 4
Universe, ppb by atom: 0.05
Discovered By: Joint Institute for Nuclear Research
Discovery Date: 1964
First Isolation: Nils Gabriel Sefström (1830)

Health, Safety & Transportation Information for Ruthenium

Ruthenium in its elemental form is considered a carcinogen. Safety data for Ruthenium and its compounds can vary widely depending on the form. For potential hazard information, toxicity, and road, sea and air transportation limitations, such as DOT Hazard Class, DOT Number, EU Number, NFPA Health rating and RTECS Class, please see the specific material or compound referenced in the Products tab. The below information applies to elemental (metallic) Ruthenium.

Safety Data
Material Safety Data Sheet MSDS
Signal Word Danger
Hazard Statements H228
Hazard Codes F
Risk Codes 11
Safety Precautions 16-22-24/25
RTECS Number N/A
Transport Information UN 3089 4.1/PG 2
WGK Germany 3
Globally Harmonized System of
Classification and Labelling (GHS)

Ruthenium Isotopes

Naturally occurring ruthenium (Ru) has seven stable isotopes: 96Ru, 98Ru, 99Ru, 100Ru, 101Ru, 102Ru and 104Ru.

Nuclide Isotopic Mass Half-Life Mode of Decay Nuclear Spin Magnetic Moment Binding Energy (MeV) Natural Abundance
(% by atom)
87Ru 86.94918(64)# 50# ms [>1.5 µs] ß+ to 87Tc 1/2-# N/A 700.99 -
88Ru 87.94026(43)# 1.3(3) s [1.2(+3-2) s] ß+ to 88Tc 0+ N/A 717.45 -
89Ru 88.93611(54)# 1.38(11) s ß+ to 89Tc (7/2)(+#) N/A 729.26 -
90Ru 89.92989(32)# 11.7(9) s ß+ to 90Tc 0+ N/A 743.86 -
91Ru 90.92629(63)# 7.9(4) s ß+ to 91Tc (9/2+) N/A 754.73 -
92Ru 91.92012(32)# 3.65(5) min ß+ to 92Tc 0+ N/A 768.4 -
93Ru 92.91705(9) 59.7(6) s ß+ to 93Tc (9/2)+ N/A 779.27 -
94Ru 93.911360(14) 51.8(6) min ß+ to 94Tc 0+ N/A 792.94 -
95Ru 94.910413(13) 1.643(14) h EC to 95Tc 5/2+ N/A 801.95 -
96Ru 95.907598(8) Observationally Stable - 0+ N/A 812.83 27.83
97Ru 96.907555(9) 2.791(4) d EC to 97Tc 5/2+ -0.78 820.91 -
98Ru 97.905287(7) STABLE - 0+ N/A 830.85 5.54
99Ru 98.9059393(22) STABLE - 5/2+ -0.6413 838.93 -
100Ru 99.9042195(22) STABLE - 0+ N/A 847.94 1.87
101Ru 100.9055821(22) STABLE - 5/2+ -0.7189 859.74 12.76
102Ru 101.9043493(22) STABLE - 0+ N/A 867.82 12.6
103Ru 102.9063238(22) 39.26(2) d ß- to 103Rh 3/2+ 0.2 875.9 17.06
104Ru 103.905433(3) Observationally Stable - 0+ N/A 883.98 31.55
105Ru 104.907753(3) 4.44(2) h ß- to 105Rh 3/2+ -0.3 892.06 -
106Ru 105.907329(8) 373.59(15) d ß- to 106Rh 0+ N/A 900.14 18.62
107Ru 106.90991(13) 3.75(5) min ß- to 107Rh (5/2)+ N/A 908.21 -
108Ru 107.91017(12) 4.55(5) min ß- to 108Rh 0+ N/A 906.98 -
109Ru 108.91320(7) 34.5(10) s ß- to 109Rh (5/2+)# N/A 915.06 -
110Ru 109.91414(6) 11.6(6) s ß- to 110Rh 0+ N/A 923.13 -
111Ru 110.91770(8) 2.12(7) s ß- to 111Rh (5/2+) N/A 931.21 -
112Ru 111.91897(8) 1.75(7) s ß- to 112Rh 0+ N/A 939.29 -
113Ru 112.92249(8) 0.80(5) s ß- to 113Rh (5/2+) N/A 938.05 -
114Ru 113.92428(25)# 0.53(6) s ß- to 114Rh; ß- + n to 113Rh 0+ N/A 946.13 -
115Ru 114.92869(14) 740(80) ms ß- to 115Rh; ß- + n to 114Rh N/A N/A 954.21 -
116Ru 115.93081(75)# 400# ms [>300 ns] ß- to 116Rh 0+ N/A 952.97 -
117Ru 116.93558(75)# 300# ms [>300 ns] ß- to 117Rh N/A N/A 961.05 -
118Ru 117.93782(86)# 200# ms [>300 ns] ß- to 118Rh 0+ N/A 969.13 -
119Ru 118.94284(75)# 170# ms [>300 ns] Unknwon N/A N/A 967.89 -
120Ru 119.94531(86)# 80# ms [>300 ns] Unknwon 0+ N/A 975.97 -
Ruthenium Elemental Symbol

Recent Research & Development for Ruthenium

  • Response of a chemical wave to local pulse irradiation in the ruthenium-catalyzed Belousov-Zhabotinsky reaction. Nakata S, Suzuki S, Ezaki T, Kitahata H, Nishi K, Nishiura Y. Phys Chem Chem Phys. 2015 Mar 11.
  • Vinyl Ruthenium-Modified Biphenyl and 2,2'-Bipyridines. Scheerer S, Rotthowe N, Abdel-Rahman OS, He X, Rigaut S, Kvapilová H, Záliš S, Winter RF. Inorg Chem. 2015 Mar 11.
  • Luminescent Ruthenium(II) Complex Bearing Bipyridine and N-Heterocyclic Carbene-based C(^)N(^)C Pincer Ligand for Live-Cell Imaging of Endocytosis. Tsui WK, Chung LH, Wong MM, Tsang WH, Lo HS, Liu Y, Leung CH, Ma DL, Chiu SK, Wong CY. Sci Rep. 2015 Mar 13
  • Quantification of bindings of organometallic ruthenium complexes to GSTΠ by mass spectrometry. Lin Y, Huang Y, Zheng W, Wu K, Luo Q, Zhao Y, Xiong S, Wang F. J Inorg Biochem. 2015 Mar 2
  • Dual Emissions from Ruthenium(II) Complexes Having 4-Arylethynyl-1,10-phenanthroline at Low Temperature. Sakuda E, Matsumoto C, Ando Y, Ito A, Mochida K, Nakagawa A, Kitamura N. Inorg Chem. 2015 Mar 6.
  • A Ruthenium-Based Biomimetic Hydrogen Cluster for Efficient Photocatalytic Hydrogen Generation from Formic Acid. Chang CH, Chen MH, Du WS, Gliniak J, Lin JH, Wu HH, Chan HF, Yu JS, Wu TK. Chemistry. 2015 Mar 12.
  • Energy Dependence of the Ruthenium(II)-Bipyridine Metal-to-Ligand-Charge-Transfer Excited State Radiative Lifetimes: Effects of ΠΠ (bipyridine) Mixing. Thomas RA, Tsai CN, Mazumder S, Lu IC, Lord RL, Schlegel HB, Chen YJ, Endicott JF. J Phys Chem B. 2015 Mar 12.
  • Ruthenium(II)-Catalyzed C?H Activation/Alkyne Annulation by Weak Coordination with O2 as the Sole Oxidant. Warratz S, Kornhaaß C, Cajaraville A, Niepötter B, Stalke D, Ackermann L. Angew Chem Int Ed Engl. 2015 Mar 3.
  • New Ruthenium Bis(terpyridine) Methanofullerene and Pyrrolidinofullerene Complexes: Synthesis and Electrochemical and Photophysical Properties. Barthelmes K, Kübel J, Winter A, Wächtler M, Friebe C, Dietzek B, Schubert US. Inorg Chem. 2015 Mar 12.
  • Ruthenium-Catalyzed Heteroatom-Directed Regioselective C-H Arylation of Indoles Using a Removable Tether. Tiwari VK, Kamal N, Kapur M. Org Lett. 2015 Mar 12.
  • Ruthenium-catalyzed aerobic oxidative decarboxylation of amino acids: a green, zero-waste route to biobased nitriles. Claes L, Verduyckt J, Stassen I, Lagrain B, De Vos DE. Chem Commun (Camb). 2015 Mar 16.
  • Ruthenium Complexes with Dendritic Ferrocenyl Phosphanes: Synthesis, Characterization, and Application in the Catalytic Redox Isomerization of Allylic Alcohols. Neumann P, Dib H, Sournia-Saquet A, Grell T, Handke M, Caminade AM, Hey-Hawkins E. Chemistry. 2015 Mar 12.
  • Excited State Dynamics and Isomerization in Ruthenium Sulfoxide Complexes. King AW, Wang L, Rack JJ. Acc Chem Res. 2015 Mar 11.
  • Enantioselective Syntheses of Sulfoxides in Octahedral Ruthenium(II) Complexes via a Chiral-at-Metal Strategy. Li ZZ, Wen AH, Yao SY, Ye BH. Inorg Chem. 2015 Mar 16
  • Revelation of Varying Bonding Motif of Alloxazine, a Flavin Analogue, in Selected Ruthenium(II/III) Frameworks. Mondal P, Ray R, Das A, Lahiri GK. Inorg Chem. 2015 Mar 16
  • Orbital entanglement and CASSCF analysis of the Ru-NO bond in a Ruthenium nitrosyl complex. Freitag L, Knecht S, Keller SF, Delcey MG, Aquilante F, Bondo Pedersen T, Lindh R, Reiher M, González L. Phys Chem Chem Phys. 2015 Mar 13.
  • Thiolate-Bridged Dinuclear Ruthenium- and Iron-Complexes as Robust and Efficient Catalysts toward Oxidation of Molecular Dihydrogen in Protic Solvents. Yuki M, Sakata K, Hirao Y, Nonoyama N, Nakajima K, Nishibayashi Y. J Am Chem Soc. 2015 Mar 10.
  • Ruthenium-Catalyzed C?C Coupling of Fluorinated Alcohols with Allenes: Dehydrogenation at the Energetic Limit of β-Hydride Elimination. Sam B, Luong T, Krische MJ. Angew Chem Int Ed Engl. 2015 Mar 10.
  • Chemiluminescence detection of MDMA in street drug samples using tris(2,2'-bipyridine)ruthenium(III). Theakstone AG, Smith ZM, Terry JM, Barnett NW, Francis PS. Drug Test Anal. 2015 Mar 9.
  • Highly Stereoselective Ruthenium(II)-Catalyzed Direct C2-syn-Alkenylation of Indoles with Alkynes. Zhang W, Wei J, Fu S, Lin D, Jiang H, Zeng W. Org Lett. 2015 Mar 6.