7440-18-8 Usage
Chemical Description
Ruthenium is a chemical element with the symbol Ru and atomic number 44.
Uses
Used in Electrical Industry:
Ruthenium is used as a hardener in electrical contact alloys and electrical filaments for its wear-resistant and high-temperature stability properties. This enhances the durability and performance of electrical components.
Used in Jewelry Industry:
Ruthenium serves as a substitute for platinum in jewelry, as well as a hardener in alloy production, making the final product more durable and resistant to wear. Its use in pen nibs also benefits from these properties, ensuring a longer-lasting writing instrument.
Used in Steel Production:
As an alloy, ruthenium is used to produce noncorrosive steel, improving the metal's resistance to corrosion and enhancing its overall performance in various applications.
Used in Medical Instruments:
Ruthenium's properties make it suitable for use in medical instruments, where its durability and resistance to wear are essential for long-lasting and reliable equipment.
Used in Solar Energy:
Ruthenium is utilized as an experimental metal for the direct conversion of solar cell material to electrical energy, showcasing its potential in renewable energy applications.
Used in Catalysts:
Ruthenium is used as a catalyst to affect the speed of chemical reactions without being altered by the process itself. This makes it a valuable component in various industrial chemical reactions, including the synthesis of long-chain hydrocarbons.
Used in Ophthalmology:
Ruthenium is also used as a drug to treat eye diseases, highlighting its potential in the medical field beyond its applications in materials science and engineering.
History, Occurrence, and Uses
Ruthenium was recognized as a new element by G.W. Osann in 1828. He found it in insoluble residues from aqua regia extract of native platinum from alluvial deposits in the Ural mountains of Russia. He named it Ruthen after the Latin name Ruthenia for Russia. The discovery of this element, however, is credited to Klaus who in 1844 found that Osann’s ruthenium oxide was very impure and isolated pure Ru metal from crude platinum residues insoluble in aqua regia.
Ruthenium occurs in nature natively, found in minor quantities associated with other platinum metals. Its abundance in the earth’s crust is estimated to be 0.001 mg/kg, comparable to that of rhodium and iridium.
Ruthenium alloyed to platinum, palladium, titanium and molybdenum have many applications. It is an effective hardening element for platinum and palladium. Such alloys have high resistance to corrosion and oxidation and are used to make electrical contacts for resistance to severe wear. Ruthenium–palladium alloys are used in jewelry, decorations, and dental work. Addition of 0.1% ruthenium markedly improves corrosion resistance of titanium. Ruthenium alloys make tips for fountain pen nibs, instrument pivots, and electrical goods. Ruthenium catalysts are used in selective hydrogenation of carbonyl groups to convert aldehydes and ketones to alcohols.
Production
Ruthenium is derived from platinum metal ores. Method of production depends on the type of ore. However, the extraction processes are similar to those of other noble metals (see Platinum, Rhodium and Iridium). Ruthenium, like Rhodium, may be obtained from accumulated anode sludges in electrolytic refining of nickel or copper from certain types of ores. Also, residues from refining nickel by Mond carbonyl process contain ruthenium and other precious metals at very low concentrations. The extraction processes are very lengthy, involving smelting with suitable fluxes and acid treatments.
Metals, such as gold, platinum, and palladium, are separated by digesting refining residues with aqua regia. These metals are soluble in aqua regia, leaving ruthenium, rhodium, iridium, osmium, and silver in the insoluble residue.
The treatment of this insoluble residue may vary. In one typical process, residue is subjected to fusion with sodium peroxide. Ruthenium and osmium are converted to water-soluble sodium ruthenate and osmate, which are leached with water. The aqueous solution is treated with chlorine gas and heated. The ruthenate and the osmate are converted to their tetroxides. Ruthenium tetroxide is distilled out and collected in hydrochloric acid. The tetroxide is converted into ruthenium chloride. Traces of osmium are removed from ruthenium chloride solution by boiling with nitric acid.
Nitric acid converts osmium to volatile osmium tetroxide but forms a nitrosyl complex with ruthenium that remains in the solution. After removal of trace osmium, the solution is treated with ammonium chloride. This precipitates ruthenium as crystals of ammonium chlororuthenate, NH4RuCl6. The precipitate is washed, dried, and ignited to form ruthenium black. This is reduced with hydrogen at 1,000°C to form very pure ruthenium powder.
Reactions
When heated in air at 500 to 700°C, ruthenium converts to its dioxide, RuO2, a black crystalline solid of rutile structure. A trioxide of ruthenium, RuO3, also is known; formed when the metal is heated above 1,000°C. Above 1,100°C the metal loses weight because trioxide partially volatilizes. Ruthenium also forms a tetroxide, RuO4, which, unlike osmium, is not produced by direct union of the elements.
Halogens react with the metal at elevated temperatures. Fluorine reacts with ruthenium at 300°C forming colorless vapors of pentafluoride, RuF5, which at ordinary temperatures converts to a green solid. Chlorine combines with the metal at 450°C to form black trichloride, RuCl3, which is insoluble in water. Ru metal at ambient temperature is attacked by chlorine water, bromine water, or alcoholic solution of iodine.
Ruthenium is stable in practically all acids including aqua regia. Fusion with an alkali in the presence of an oxidizing agent forms ruthenate, RuO42– and perruthenate, RuO4ˉ.
When finely-divided Ru metal is heated with carbon monoxide under 200 atm pressure, ruthenium converts to pentacarbonyl, Ru(CO)5, a colorless liquid that decomposes on heating to diruthenium nonacarbonyl, Ru2(CO)9, a yellow crystalline solid. Ruthenium reacts with cyclopentadiene in ether to form a sandwich complex, a yellow crystalline compound, bis(cyclopentadiene) ruthenium(0), also known as ruthenocene.
Isotopes
There are 37 isotopes for ruthenium, ranging in atomic mass numbers from87 to 120. Seven of these are stable isotopes. The atomic masses and percentage ofcontribution to the natural occurrence of the element on Earth are as follows: Ru-96 =5.54%, Ru-98 = 1.87%, Ru-99 = 12.76%, Ru-100 = 12.60%, Ru-101 = 17.06%, Ru-102 = 31.55%, and Ru-104 = 18.62%.
Origin of Name
“Ruthenium” is derived from the Latin word Ruthenia meaning “Russia,”
where it is found in the Ural Mountains.
Characteristics
Ruthenium also belongs to the platinum group, which includes six elements with similarchemical characteristics. They are located in the middle of the second and third series of thetransition elements. The platinum group consists of ruthenium, rhodium,palladium, osmium, iridium, and platinum.Ruthenium is a hard brittle metal that resists corrosion from all acids but is vulnerable tostrong alkalis (bases). Small amounts, when alloyed with other metals, will prevent corrosionof that metal.
History
Berzelius and Osann in 1827 examined the residues left after dissolving crude platinum from the Ural
mountains in aqua regia. While Berzelius found no unusual
metals, Osann thought he found three new metals, one of
which he named ruthenium. In 1844 Klaus, generally recognized
as the discoverer, showed that Osann’s ruthenium oxide
was very impure and that it contained a new metal. Klaus
obtained 6 g of ruthenium from the portion of crude platinum
that is insoluble in aqua regia. A member of the platinum
group, ruthenium occurs native with other members of
the group of ores found in the Ural mountains and in North
and South America. It is also found along with other platinum
metals in small but commercial quantities in pentlandite of
the Sudbury, Ontario, nickel-mining region, and in pyroxinite
deposits of South Africa. Natural ruthenium contains seven
isotopes. Twenty-eight other isotopes and isomers are known,
all of which are radioactive. The metal is isolated commercially
by a complex chemical process, the final stage of which
is the hydrogen reduction of ammonium ruthenium chloride,
which yields a powder. The powder is consolidated by powder
metallurgy techniques or by argon-arc welding. Ruthenium is
a hard, white metal and has four crystal modifications. It does
not tarnish at room temperatures, but oxidizes in air at about
800°C. The metal is not attacked by hot or cold acids or aqua
regia, but when potassium chlorate is added to the solution,
it oxidizes explosively. It is attacked by halogens, hydroxides,
etc. Ruthenium can be plated by electrodeposition or by thermal
decomposition methods. The metal is one of the most effective
hardeners for platinum and palladium, and is alloyed
with these metals to make electrical contacts for severe wear
resistance. A ruthenium–molybdenum alloy is said to be superconductive
at 10.6 K. The corrosion resistance of titanium
is improved a hundredfold by addition of 0.1% ruthenium. It
is a versatile catalyst. Hydrogen sulfide can be split catalytically
by light using an aqueous suspension of CdS particles
loaded with ruthenium dioxide. It is thought this may have
application to removal of H2S in oil refining and other industrial
processes. Compounds in at least eight oxidation states
have been found, but of these, the +2. +3. and +4 states are the
most common. Ruthenium tetroxide, like osmium tetroxide,
is highly toxic. In addition, it may explode. Ruthenium compounds
show a marked resemblance to those of osmium. The
metal is priced at about $25/g (99.95% pure).
Production Methods
Elemental ruthenium occurs in native alloys of iridium and
osmium (irridosmine, siskerite) and in sulfide and other ores
(pentlandite, laurite, etc.) in very small quantities that are
commercially recovered.
The element is separated from the other platinum metals
by a sequence involving treatment with aqua regia (separation
of insoluble osmium, rhodium, ruthenium, and iridium),
fusion with sodium bisulfate (with which rhodium reacts),
and fusion with sodium peroxide (dissolution of osmium and
ruthenium). The resulting solution of ruthenate and osmate is
treated with ethanol to precipitate ruthenium dioxide. The
ruthenium dioxide is purified by treatment with hydrochloric
acid and chlorine and reduced with hydrogen gas to pure
metal.
Ruthenium is recovered from exhausted catalytic converters
or, in a similar manner, from the waste produced during
platinum and nickel ore processing.
Hazard
The main hazard is the explosiveness of ruthenium fine power or dust. The metal willrapidly oxidize (explode) when exposed to oxidizer-type chemicals such as potassium chlorideat room temperature. Most of its few compounds are toxic and their fumes should beavoided.
Flammability and Explosibility
Notclassified
Pharmaceutical Applications
Ruthenium is the chemical element with the symbol Ru and atomic number 44. It occurs as a minor side
product in the mining of platinum. Ruthenium is relatively inert to most chemicals. Its main applications are
in the area of specialised electrical parts.
The success of cisplatin, together with the occurrence of dose-limiting resistances and severe side effects
such as nausea and nephrotoxicity, encouraged the research into other metal-based anticancer agents. Ruthenium
is one of those metals under intense research, and first results look very promising, with two candidates
– NAMI-A and KP1019 – having entered clinical trials.
Safety Profile
Most ruthenium compounds are poisons. Ruthenium is retained in the bones for a long time. Flammable in the form of dust when exposed to heat or flame. Violent reaction with ruthenium oxide. Explosive reaction with aqua rega + potassium chlorate. When heated to decomposition it emits very toxic fumes of RuO, and Ru, which are hghly injurious to the eyes and lung and can
produce nasal ulcerations. See also RUTHENIUM COMPOUNDS.
Check Digit Verification of cas no
The CAS Registry Mumber 7440-18-8 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 7,4,4 and 0 respectively; the second part has 2 digits, 1 and 8 respectively.
Calculate Digit Verification of CAS Registry Number 7440-18:
(6*7)+(5*4)+(4*4)+(3*0)+(2*1)+(1*8)=88
88 % 10 = 8
So 7440-18-8 is a valid CAS Registry Number.
InChI:InChI=1/C11H9ClN2/c12-8-9-2-4-10(5-3-9)11-13-6-1-7-14-11/h1-7H,8H2
7440-18-8Relevant academic research and scientific papers
Johnson, Brian F. G.,Lewis, Jack,Aime, Silvio,Milone, Luciano,Osella, Domenico
, p. 247 - 252 (1982)
The reaction of styrene with Ru3(CO)12 yields the known complex Ru4(CO)12(PhC=CH) and the new cluster Ru4(CO)9(PhC=CH)(PhEt), in which a second molecule of styrene is hydrogenated and η6-bonded.
Wei,Li,Luo,Yan,Sun,Yin,Shen
, p. 26055 - 26061 (2006)
The electrochemical oxidation of methanol has been investigated on underpotentially deposited-ruthenium-modified platinum electrode (upd-Ru/Pt) and on underpotentially deposited-tin-modified platinum electrode (upd-Sn/Pt). The submonolayers of upd-Ru and upd-Sn on a Pt electrode increased the rate of methanol electrooxidation several times as large as that on a pure Pt electrode. The best performance for methanol electrooxidation was obtained on a ternary platinum based catalyst modified by upd-Ru and upd-Sn simultaneously. The influence of the submonolayers of upd-Ru adatoms and upd-Sn adatoms on the oxidation of methanol in acid has been investigated. The effect of Ru on methanol electrooxidation lies on the distribution of Ru adatoms on a Pt surface. It has been shown that as long as the amount of upd-Ru deposits were controlled in a proper range, upd-Ru deposits would enhance the methanol oxidation obtained on a Pt electrode at whichever deposition potential the upd-Ru deposits were obtained. The effects of tin are sensible to the potential range. The enhancement effect of upd-Sn adatoms for the oxidation of methanol will disappear as the electrode potential is beyond a certain value. It is speculated that there exists a synergetic effect on the Pt electrode as adatoms Ru and Sn participate simultaneously in the methanol oxidation.
Lewerenz,Michaelis
, p. 913 - 916 (1988)
The authors restrict this investigation to Ru/InP and Ru/GaInPAs contacts. The large grain polycrystalline quaternary semiconductor has been chosen because of differences in surface chemistry. Experimental data show that the typical current enhancement upon metallization is found. The increase in catalytic activity is larger for InP. A somewhat lower overall photoactivity is noted for GaInPAs.
Cao, Dianxue,Bergens, Steven H.
, p. 4021 - 4031 (2003)
The surface of Pt nanoparticles was cleaned and saturated with hydrogen by treatment first with a 3% aqueous solution of H2O2 and then with hydrogen gas under water at room temperature. Reaction between the surface hydrogen and aqueous RuCl3 deposited 0.18 surface equivalents of Ruad onto the Pt nanoparticles. The deposition was repeated several times, with each reaction depositing ～0.18 surface equivalents more Ruad onto the Pt-Ruad nanoparticles. The resulting Pt-Ruad nanoparticles were analysed using cyclic voltammetry, CO stripping voltammetry, and as catalysts for electrooxidation of MeOH in three-electrode experiments and in prototype direct methanol fuel cells. The optimum surface coverage (θRu) for electrooxidation of MeOH was ～ 0.33 under these conditions.
Lee, Sang Young,Kim, Seong Keun,Kim, Kyung Min,Choi, Gyu-Jin,Han, Jeong Hwan,Hwang, Cheol Seong
, p. G47-G51 (2011)
Ru top electrode etching techniques for Ru/Ti O2 /Ru (RTR) thin film capacitor fabrication were examined. A dry etching process using a plasma mixture of O2, Cl2, and Ar gases deteriorated the leakage current properties significantly, which were not recovered by postannealing processes. The surface roughness was not a critical factor in determining the leakage characteristics. The etching damage along the etched edges was not the main cause of the leakage degradation but it was observed over the entire area, which was confirmed according to a comparison of capacitors with different perimeter/area ratios. For the wet etching of Ru films, the etch rates were evaluated using a periodic acid solution at various concentrations at 60°C. The Ru films etched using a 14 wt % periodic acid solution showed a moderate etch rate and a reasonable etching selectivity on the Ti O2 and Al2 O3 films. The as-wet-etched RTR capacitors showed a lower leakage current level than the dry-etched capacitors. Furthermore, the electrical properties of the wet-etched capacitor were improved significantly by a postannealing process.
Kang, Sang Yeol,Choi, Kook Hyun,Lee, Seok Kiu,Hwang, Cheol Seong,Kim, Hyeong Joon
, p. 1161 - 1167 (2000)
The equilibrium concentrations of the various gaseous and solid phases in metallorganic chemical vapor deposition of Ru thin films were calculated in the experimentally relevant temperature and oxygen partial pressure ranges. Although thermal decomposition of the precursor, bis(ethyl-π-cyclopentadienyl)Ru [Ru(EtCp)2] required a sufficient amount of oxygen, experimental results showed that up to a certain concentration of oxygen, Ru metal was deposited without any detectable RuO2 impurity. Thermodynamic calculations showed that all the supplied oxygen was consumed to oxidize carbon and hydrogen, cracked from the precursor ligand, rather than Ru. Thus, metal films could be obtained. There was an optimum oxygen-to-precursor ratio at which the pure Ru phase could be obtained with minimum generation of not only carbon and RuO2 but also detrimental hydrogen. Ru thin films with minimal carbon and RuO2 contamination could be obtained by optimization of the oxygen supply at a low deposition temperature at 300°C.
Borodin,Kostin,Plusnin,Filatov,Bogomyakov,Kuratieva
, p. 2298 - 2304 (2012)
Five new heterometallic complexes with a {Ln[RuNO(μ-NO2) 4(μ3-OH)]2Ln} (Ln = Ce, Pr, Nd, Eu) core were prepared by reaction of Na2[RuNO(NO2)4OH] and lanthanide nitrates in the presence of pyridine. The crystal structures of the obtained compounds were determined by single-crystal X-ray analysis. In all complexes, Ru and Ln atoms are connected by N,O-bridging nitrite groups and OH groups. The coordination environment of Ln3+ is completed by oxygen atoms of nitrate ions and water molecules and by nitrogen atoms of pyridine molecules. Magnetic interactions between lanthanide atoms become apparent at temperatures lower than 40-50 K, and at temperatures higher than 100 K, the dependencies of the magnetic susceptibilities of the complexes are well explained by the presence of two noninteracting paramagnetic centers. Thermal decomposition of the investigated complexes in an inert atmosphere results in a mixture of metallic ruthenium and the corresponding lanthanide oxide. Formation of mixed oxide phases RuPrOx was also detected after decomposition of the praseodymium complex. The reaction of lanthanide (Ce, Pr, Nd, Eu) nitrates with Na2[RuNO(NO2)4OH] in the presence of pyridine results in the formation of tetranuclear heterometallic complexes. The crystal structures, thermal, and magnetic properties of the obtained compounds are reported. Copyright
Walker, Jeremy,Bruce King,Tannenbaum, Rina
, p. 2290 - 2297 (2007)
Hydrous ruthenium oxide (RuO2·xH2O) xerogels were synthesized through the addition of a 1,2-epoxide, propylene oxide, to commercial hydrated ruthenium chloride, RuCl3·xH2O, in ethanol. After a blue-black monolithic gel formed in 4 h, the samples were allowed to age for 24 h and were dried in ambient conditions. The dried samples were then characterized by XPS, XRD, DTA and TGA. XPS showed the Ru(3d5/2) peak at a binding energy of 281.7 eV, corresponding to that of hydrous ruthenium oxide. XRD data revealed the synthesized material as amorphous. Heating the sample in inert atmospheres caused the complete reduction of the oxide to the zero-valent state, whereas heating the sample in air resulted in both crystalline anhydrous RuO2 and zero-valent ruthenium, depending on the method of heating. DTA traces showed an endotherm ending at 150 °C, corresponding to the loss of coordinated water, as well as two higher temperature crystallization exotherms when the sample was heated in both inert and oxygen-rich atmospheres. TGA runs also confirmed the complete reduction of the hydrous oxide when heated in nitrogen below 270 °C and the formation of anhydrous ruthenium oxide when heated in air, confirming the XRD results.
Omar
, p. 607 - 615 (2009)
Complexes resulted from the interaction of [Ph3P] 3RuCl2 with 2-aminoethylpyridine (aepy), 2-hydrazinopyridine (hzpy) and dipicolylamine (dpa) with KPF6 have been isolated from ethanol. The structures of the com
Kwon, Oh-Kyum,Kwon, Se-Hun,Park, Hyoung-Sang,Kang, Sang-Won
, p. C753-C756 (2004)
Ruthenium thin films were produced by plasma-enhanced atomic layer deposition (PEALD) using an alternating supply of bis(ethylcyclopentadienyl)ruthenium [Ru(EtCp)2] and NH3 plasma at a deposition temperature of 270°C. The film thickness per cycle was self-limited at 0.038 nm/cycle, which was thinner than the thickness obtained from the conventional ALD using oxygen instead of NH3 plasma. The ruthenium thin film prepared with PEALD had a preferential orientation toward (002), and it was progressively promoted with NH3 plasma power. The PEALD of ruthenium shows a merit in controlling ultrathin film thickness with less than 2 nm more precisely and more easily than the conventional ALD, due to the reduced transient period at the initial film growth stage. Also, ruthenium thin film improved the interfacial adhesion of metallorganic chemical vapor deposited copper to diffusion barrier metals by forming Cu-Ru chemical bonds at the interface without degrading the film resistivity of copper.
