Skip to Main Content

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.

+ Open All
- Close All

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
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)
Review and Print SDS for Ruthenium Metal


Date Created: 05/15/2015
Date Revised: 05/15/2015


Product Name: Ruthenium Metal

Product Number: All applicable American Elements product codes, e.g. RU-M-02, RU-M-03, RU-M-04, RU-M-05

CAS #: 7440-18-8

Relevant identified uses of the substance: Scientific research and development

Supplier details:
American Elements
1093 Broxton Ave. Suite 2000
Los Angeles, CA 90024
Tel: +1 310-208-0551
Fax: +1 310-208-0351

Emergency telephone number:
Domestic, North America +1 800-424-9300
International +1 703-527-3887


Classification of the substance or mixture
Classification according to Regulation (EC) No 1272/2008
The substance is not classified as hazardous to health or the environment according to the CLP regulation.
Classification according to Directive 67/548/EEC or Directive 1999/45/EC
Not applicable
Information concerning particular hazards for human and environment:
No information known.
Hazards not otherwise classified
No information known.
Label elements
Labelling according to Regulation (EC) No 1272/2008
Not applicable
Hazard pictograms
Not applicable
Signal word
Not applicable
Hazard statements
Not applicable
WHMIS classification
Not controlled
Classification system
HMIS ratings (scale 0-4)
(Hazardous Materials Identification System)

Health (acute effects) = 0
Flammability = 0
Physical Hazard = 0
Other hazards
Results of PBT and vPvB assessment
Not applicable.
Not applicable.


Chemical characterization: Substances
CAS# Description:
7440-18-8 Ruthenium
Identification number(s):
EC number:


Description of first aid measures
General information
No special measures required.
After inhalation
Seek medical treatment in case of complaints.
After skin contact
Generally the product does not irritate the skin.
After eye contact
Rinse opened eye for several minutes under running water. If symptoms persist, consult a doctor.
After swallowing
If symptoms persist consult doctor.
Information for doctor
Most important symptoms and effects, both acute and delayed
No further relevant information available.
Indication of any immediate medical attention and special treatment needed
No further relevant information available.


Extinguishing media
Suitable extinguishing agents
Special powder for metal fires. Do not use water.
For safety reasons unsuitable extinguishing agents
Special hazards arising from the substance or mixture
If this product is involved in a fire, the following can be released:
Metal oxide fume
Advice for firefighters
Protective equipment:
No special measures required


Personal precautions, protective equipment and emergency procedures
Not required.
Environmental precautions:
Do not allow material to be released to the environment without proper governmental permits.
Do not allow product to reach sewage system or any water course.
Do not allow to penetrate the ground/soil.
Methods and material for containment and cleaning up:
Pick up mechanically.
Prevention of secondary hazards:
No special measures required.
Reference to other sections
See Section 7 for information on safe handling
See Section 8 for information on personal protection equipment.
See Section 13 for disposal information.


Precautions for safe handling
Keep container tightly sealed.
Store in cool, dry place in tightly closed containers.
Information about protection against explosions and fires:
No special measures required.
Conditions for safe storage, including any incompatibilities
Requirements to be met by storerooms and receptacles:
No special requirements.
Information about storage in one common storage facility:
Store away from mineral acids
Further information about storage conditions:
Keep container tightly sealed.
Store in cool, dry conditions in well sealed containers.
Specific end use(s)
No further relevant information available.


Additional information about design of technical systems:
No further data; see section 7.
Control parameters
Components with limit values that require monitoring at the workplace:
The product does not contain any relevant quantities of materials with critical values
that have to be monitored at the workplace.
Additional information:
No data
Exposure controls
Personal protective equipment
General protective and hygienic measures
The usual precautionary measures for handling chemicals should be followed.
Maintain an ergonomically appropriate working environment.
Breathing equipment:
Not required.
Protection of hands:
Not required.
Penetration time of glove material (in minutes)
Not determined
Eye protection:
Safety glasses
Body protection:
Protective work clothing.


Information on basic physical and chemical properties
General Information
Form: Solid in various forms
Color: Silver-colored
Odor: Odorless
Odor threshold: Not determined.
pH-value: Not applicable.
Change in condition
Melting point/Melting range: 2334 °C (4233 °F)
Boiling point/Boiling range: 4150 °C (7502 °F)
Sublimation temperature / start: Not determined
Flammability (solid, gaseous)
Not determined.
Ignition temperature: Not determined
Decomposition temperature: Not determined
Auto igniting: Not determined.
Danger of explosion: Not determined.
Explosion limits:
Lower: Not determined
Upper: Not determined
Vapor pressure: Not applicable.
Density at 20 °C (68 °F): 12.45 g/cm³ (103.895 lbs/gal)
Relative density
Not determined.
Vapor density
Not applicable.
Evaporation rate
Not applicable.
Solubility in / Miscibility with Water: Insoluble
Partition coefficient (n-octanol/water): Not determined.
dynamic: Not applicable.
kinematic: Not applicable.
Other information
No further relevant information available.


No information known.
Chemical stability
Stable under recommended storage conditions.
Thermal decomposition / conditions to be avoided:
Decomposition will not occur if used and stored according to specifications.
Possibility of hazardous reactions
No dangerous reactions known
Conditions to avoid
No further relevant information available.
Incompatible materials:
Mineral acids
Hazardous decomposition products:
Metal oxide fume


Information on toxicological effects
Acute toxicity:
No effects known.
LD/LC50 values that are relevant for classification:
No data
Skin irritation or corrosion:
No irritant effect
Eye irritation or corrosion:
No irritant effect.
No sensitizing effects known.
Germ cell mutagenicity:
No effects known.
No classification data on carcinogenic properties of this material is available from the EPA, IARC, NTP, OSHA or ACGIH.
Reproductive toxicity:
No effects known.
Specific target organ system toxicity - repeated exposure:
No effects known.
Specific target organ system toxicity - single exposure:
No effects known.
Aspiration hazard:
No effects known.
Subacute to chronic toxicity:
No effects known.
Additional toxicological information:
To the best of our knowledge the acute and chronic toxicity of this substance is not fully known.


Aquatic toxicity:
No further relevant information available.
Persistence and degradability
No further relevant information available.
Bioaccumulative potential
No further relevant information available.
Mobility in soil
No further relevant information available.
Additional ecological information:
General notes:
Do not allow material to be released to the environment without proper governmental permits.
Avoid transfer into the environment.
Results of PBT and vPvB assessment
Not applicable.
Not applicable.
Other adverse effects
No further relevant information available.


Waste treatment methods
Consult state, local or national regulations to ensure proper disposal.
Uncleaned packagings:
Disposal must be made according to official regulations.


Not applicable
UN proper shipping name
Not applicable
Transport hazard class(es)
Not applicable
Packing group
Not applicable
Environmental hazards:
Not applicable.
Special precautions for user
Not applicable.
Transport in bulk according to Annex II of MARPOL73/78 and the IBC Code
Not applicable.
Transport/Additional information:
Marine Pollutant (DOT):


Safety, health and environmental regulations/legislation specific for the substance or mixture
National regulations
All components of this product are listed in the U.S. Environmental Protection Agency Toxic Substances Control Act Chemical substance Inventory.
All components of this product are listed on the Canadian Domestic Substances List (DSL).
SARA Section 313 (specific toxic chemical listings)
Substance is not listed.
California Proposition 65
Prop 65 - Chemicals known to cause cancer
Substance is not listed.
Prop 65 - Developmental toxicity
Substance is not listed.
Prop 65 - Developmental toxicity, female
Substance is not listed.
Prop 65 - Developmental toxicity, male
Substance is not listed.
Information about limitation of use:
For use only by technically qualified individuals.
Other regulations, limitations and prohibitive regulations
Substance of Very High Concern (SVHC) according to the REACH Regulations (EC) No. 1907/2006.
Substance is not listed.
The conditions of restrictions according to Article 67 and Annex XVII of the Regulation (EC) No 1907/2006 (REACH) for the manufacturing, placing on the market and use must be observed.
Substance is not listed.
Annex XIV of the REACH Regulations (requiring Authorisation for use)
Substance is not listed.
REACH - Pre-registered substances
Substance is listed.
Chemical safety assessment:
A Chemical Safety Assessment has not been carried out.


Safety Data Sheet according to Regulation (EC) No. 1907/2006 (REACH). The above information is believed to be correct but does not purport to be all inclusive and shall be used only as a guide. The information in this document is based on the present state of our knowledge and is applicable to the product with regard to appropriate safety precautions. It does not represent any guarantee of the properties of the product. American Elements shall not be held liable for any damage resulting from handling or from contact with the above product. See reverse side of invoice or packing slip for additional terms and conditions of sale. COPYRIGHT 1997-2016 AMERICAN ELEMENTS. LICENSED GRANTED TO MAKE UNLIMITED PAPER COPIES FOR INTERNAL USE ONLY.

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 -