7704-34-9 Usage
Chemical Description
Sulfur is a chemical element.
Chemical Description
Sulfur is a yellow solid that is used in the production of sulfuric acid.
Chemical Description
Sulfur is a nonmetallic element that is often used in organic synthesis as a reducing agent or to promote cyclization reactions.
Chemical Description
Sulfur and chloranil are used in attempts to dehydrogenate some of the addition products, while bromine is used in the synthesis of tetrabromide of 1,4-diphenylbutadiene.
Chemical Description
Sulfur is used as a reagent in the reactions to form the sulfur-containing rings.
Uses
Used in Pharmaceutical Industry:
Sulfur is used as an ingredient in acne soaps and lotions for reducing oil-gland activity and dissolving the skin's surface layer of dry, dead cells. It is also used as a mild antiseptic in acne creams and lotions, stimulating healing when used on skin rashes. However, it may cause skin irritation and allergic skin reactions.
Used in Chemical Industry:
Sulfur is one of the four major commodities of the chemical industry, along with limestone, coal, and salt. It is primarily used to manufacture sulfuric acid (H2SO4), with forty million tons produced each year for various applications. Sulfur is also used in the production of fertilizers, lead-acid batteries, gunpowder, desiccants, matches, soaps, plastics, bleaching agents, rubber, road asphalt binders, insecticides, paint, dyes, and medical ointments, among many other uses.
Used in Agriculture:
Sulfur is a macronutrient required by plants in relatively large amounts. It is used to increase the acidity of soil and correct sulfur deficiency in plants. Sulfur is essential for the synthesis of amino acids, which are essential components of proteins. It also plays a role in chlorophyll synthesis and is part of ferridoxins, a type of non-heme iron-sulfur protein involved in the reduction of nitrite and sulfate and the assimilation of nitrogen by bacteria.
Used in Rubber Industry:
Elemental sulfur is used for vulcanizing rubber, a process that improves the elasticity, strength, and durability of rubber products.
Used in Mining and Explosives:
Sulfur is used in the production of black gunpowder, which is an explosive substance used in mining and other applications.
Used in Soil Conditioning and Fungicides:
Sulfur is used as a soil conditioner and as a fungicide to protect plants from fungal diseases.
Used in Metal Sulfides Production:
Sulfur is used in the preparation of a number of metal sulfides, which have various applications in different industries.
Used in Carbon Disulfide Production:
Sulfur is used in the production of carbon disulfide, which has various applications in the chemical industry.
Used in Matches and Bleaching:
Sulfur is used in the manufacturing of matches and for bleaching wood pulp, straw, silk, and wool.
Used in Dye Synthesis:
Sulfur is used in the synthesis of many dyes, contributing to the production of various colored products.
Used as Scabicides and Antiseptics:
Pharmaceutical grade precipitated and sublimed sulfurs are used as scabicides and as antiseptics in lotions and ointments, helping to treat skin conditions and prevent infections.
Isotopes
There are a total of 24 isotopes of sulfur; all but four of these are radioactive.The four stable isotopes and their contribution to sulfur’s total abundance on Earth areas follows: S-32 contributes 95.02% to the abundance of sulfur; S-33, just 0.75%; S-34,4.21%; and S-36, 0.02%.
Origin of Name
From the Sanskrit word sulvere and the Latin word sulphurim.
Characteristics
Sulfur exhibits a remarkable array of unique characteristics. Today, there are chemistsdevoting large portions of their careers to studying this unusual element. For example, whensulfur is melted, its viscosity increases, and it turns reddish-black as it is heated. Beyond200°C, the color begins to lighten, and it flows as a thinner liquid.Sulfur burns with a beautiful subdued blue flame. The old English name for sulfur was“brimstone,” which means “a stone that burns.” This is the origin of the term “fire and brimstone”when referring to great heat. Above 445°C, sulfur turns to a gas, which is dark orangeyellowbut which becomes lighter in color as the temperature rises.Sulfur is an oxidizing agent and has the ability to combine with most other elements toform compounds.
History
Sulfur was known to the alchemists from ancient times as brimstone. Lavoisier in 1772 proved sulfur to be an element. The element derived its name from both the Sanskrit and Latin names Sulvere and Sulfurium, respectively. Sulfur is widely distributed in nature, in earth's crust, ocean, meteorites, the moon, sun, and certain stars. It also is found in volcanic gases, natural gases, petroleum crudes, and hot springs. It is found in practically all plant and animal life. Most natural sulfur is in iron sulfides in the deep earth mantle. The abundance of sulfur in earth’s crust is about 350 mg/kg. Its average concentration in seawater is estimated to be about 0.09%. Sulfur occurs in earth’s crust as elemental sulfur (often found in the vicinity of volcanoes), sulfides, and sulfates. The most important sulfur-containing ores are iron pyrite, FeS2; chalcopyrite, CuFeS2; sphalerite, ZnS; galena, PbS; cinnabar HgS; gypsum CaSO4?2H2O; anhydrite CaSO4; kieserite, MgSO4?H2O; celestite, SrSO4; barite, BaSO4; and. stibnite, Sb2S3.
History
Sulfur is found
in meteorites. A dark area near the crater Aristarchus on the
moon has been studied by R. W. Wood with ultraviolet light.
This study suggests strongly that it is a sulfur deposit. Sulfur
occurs native in the vicinity of volcanoes and hot springs. It is
widely distributed in nature as iron pyrites, galena, sphalerite,
cinnabar, stibnite, gypsum, Epsom salts, celestite, barite, etc.
Sulfur is commercially recovered from wells sunk into the salt
domes along the Gulf Coast of the U.S. It is obtained from
these wells by the Frasch process, which forces heated water
into the wells to melt the sulfur, which is then brought to the
surface. Sulfur also occurs in natural gas and petroleum crudes
and must be removed from these products. Formerly this was
done chemically, which wasted the sulfur. New processes
now permit recovery, and these sources promise to be very
important. Large amounts of sulfur are being recovered from
Alberta gas fields. Sulfur is a pale yellow, odorless, brittle solid
that is insoluble in water but soluble in carbon disulfide. In every
state, whether gas, liquid or solid, elemental sulfur occurs
in more than one allotropic form or modification; these present
a confusing multitude of forms whose relations are not yet
fully understood. Amorphous or “plastic” sulfur is obtained
by fast cooling of the crystalline form. X-ray studies indicate
that amorphous sulfur may have a helical structure with eight
atoms per spiral. Crystalline sulfur seems to be made of rings,
each containing eight sulfur atoms that fit together to give a
normal X-ray pattern. Twenty-one isotopes of sulfur are now
recognized. Four occur in natural sulfur, none of which is radioactive.
A finely divided form of sulfur, known as flowers
of sulfur, is obtained by sublimation. Sulfur readily forms sulfides
with many elements. Sulfur is a component of black gunpowder,
and is used in the vulcanization of natural rubber and
a fungicide. It is also used extensively is making phosphatic
fertilizers. A tremendous tonnage is used to produce sulfuric
acid, the most important manufactured chemical. It is used
in making sulfite paper and other papers, as a fumigant, and
in the bleaching of dried fruits. The element is a good electrical
insulator. Organic compounds containing sulfur are very
important. Calcium sulfate, ammonium sulfate, carbon disulfide,
sulfur dioxide, and hydrogen sulfide are but a few of the
many other important compounds of sulfur. Sulfur is essential
to life. It is a minor constituent of fats, body fluids, and skeletal
minerals. Carbon disulfide, hydrogen sulfide, and sulfur
dioxide should be handled carefully. Hydrogen sulfide in small
concentrations can be metabolized, but in higher concentrations
it can quickly cause death by respiratory paralysis. It is
insidious in that it quickly deadens the sense of smell. Sulfur
dioxide is a dangerous component in atmospheric pollution.
Sulfur (99.999%) costs about $575/kg.
Production Methods
Elemental sulfur is recovered from its ore deposits found throughout the world. It is obtained commercially by the Frasch process, recovery from wells sunk into salt domes. Heated water under pressure is forced into the underground deposits to melt sulfur. Liquid sulfur is then brought to the surface. Sulfur is recovered by distillation. Often the ore is concentrated by froth flotation.
Elemental sulfur also is recovered as a by-product in processing natural gas and petroleum. Refining operations of natural gas and petroleum crude produce hydrogen sulfide, which also may occur naturally. Hydrogen sulfide is separated from hydrocarbon gases by absorption in an aqueous solution of alkaline solvent such as monoethanol amine. Hydrogen sulfide is concentrated in this solvent and gas is stripped out and oxidized by air at high temperature in the presence of a catalyst (Claus process).
Elemental sulfur also may be obtained by smelting sulfide ores with a reducing agent, such as coke or natural gas, or by reduction of sulfur dioxide.
Reactions
Sulfur forms two oxides, sulfur dioxide, SO2, and the trioxide, SO3. It burns in oxygen at about 250°C or in air above 260°C, forming sulfur dioxide. In excess oxygen the trioxide is obtained.
Sulfur reacts with hydrogen at 260 to 350°C forming hydrogen sulfide. The reaction is slow at this temperature and does not go to completion. The reaction is catalyzed by activated alumina.
Reactions with excess chlorine or fluorine yield sulfur tetrachloride, SCl4, or hexafluoride, SF6. These reactions occur under cold conditions.
Sulfur reacts with sulfur dioxide in an electric discharge to form disulfuroxide, S2O.
Sulfur reacts with aqueous sulfide to form polysulfides: S + Na2S → Na2S2
With aqueous solution of sulfite the product is thiosulfate:
S + SO32– → S2O32–
Thiosulfate also is obtained by heating sulfur with powdered sulfite:
S + Na2SO3 → Na2S2O3
When heated with alkali cyanide, thiocyanate salt is obtained:
S + KCN → KSCN
A similar reaction occurs in the aqueous phase in which thiocyanate is obtained by evaporation and crystallization.
Sulfur combines with alkali metals, copper, silver, and mercury on cold contact with the solid, forming sulfides. Reactions with magnesium, zinc, and cadmium occur to a small degree at ordinary temperatures, but rapidly on heating. Sulfur reacts with phosphorus, arsenic, antimony, bismuth, and silicon at their melting points and with other elements at elevated temperatures forming binary sulfides. Sulfides of tellurium, gold, platinum, and iridium are difficult to obtain even at elevated temperatures. Sulfur does not react with inert gases, nitrogen, and iodine.
Air & Water Reactions
Flammable. Insoluble in water.
Reactivity Profile
SULFUR reacts violently with strong oxidizing agents causing fire and explosion hazards [Handling Chemicals Safely 1980 p. 871]. Reacts with iron to give pyrophoric compounds. Attacks copper, silver and mercury. Reacts with bromine trifluoride, even at 10°C [Mellor 2:113. 1946-47]. Ignites in fluorine gas at ordinary temperatures [Mellor 2:11-13 1946-47]. Reacts to incandescence with heated with thorium [Mellor 7:208 1946-47]. Can react with ammonia to form explosive sulfur nitride. Reacts with calcium phosphide incandescently at about 300°C. Reacts violently with phosphorus trioxide [Chem. Eng. News 27:2144 1949]. Mixtures with ammonium nitrate or with metal powders can be exploded by shock [Kirk and Othmer 8:644]. Combinations of finely divided sulfur with finely divided bromates, chlorates, or iodates of barium, calcium, magnesium, potassium, sodium, or zinc can explode with heat, friction, percussion, and sometimes light [Mellor 2 Supp.1:763. 1956]. A mixture with barium carbide heated to 150°C becomes incandescent. Reacts incandescently with calcium carbide or strontium carbide at 500°C. Attacks heated lithium, or heated selenium carbide with incandescence [Mellor 5:862 1946-47]. Reacts explosively if warmed with powdered zinc [Mellor 4:476. 1946-47]. Reacts vigorously with tin [Mellor 7:328. 1946-47]. A mixture with potassium nitrate and arsenic trisulfide is a known pyrotechnic formulation [Ellern 1968 p. 135]. Mixtures with any perchlorate can explode on impact [ACS 146:211-212]. A mixture of damp sulfur and calcium hypochlorite produces a brilliant crimson flash with scatter of molten sulfur [Chem. Eng. News 46(28):9 1968]. Takes fire spontaneously in chlorine dioxide and may produce an explosion [Mellor 2:289 (1946-47)]. Ignites if heated with chromic anhydride ignite and can explode, [Mellor 10:102 (1946-47)]. Even small percentages of hydrocarbons in contact with molten sulfur generate hydrogen sulfide and carbon disulfide, which may accumulate in explosive concentrations. Sulfur reacts with Group I metal nitrides to form flammable mixtures, evolving flammable and toxic NH3 and H2S gasses if water is present. (Mellor, 1940, Vol. 8, 99).
Hazard
Many of the sulfur compounds are toxic but essential for life. The gas from elemental sulfurand from most of the compounds of sulfur is poisonous when inhaled and deadly wheningested. This is the reason that sulfur compounds are effective for rat and mice exterminationas well an ingredient of insecticides. Sulfa drugs (sulfanilamide and sufadiazine), althoughtoxic, were used as medical antibiotics during World War II before the development of penicillin.They are still used today in veterinary medicine.
Health Hazard
Can cause eye irritation; may rarely irritate skin. If recovered sulfur, refer to hydrogen sulfide.*
Flammability and Explosibility
Nonflammable
Safety Profile
Poison by ingestion, intravenous, and intraperitoneal routes. A human eye irritant. A fungcide. Chronic inhalation can cause irritation of mucous membranes. Combustible when exposed to heat or flame or by chemical reaction with oxidzers. Explosive in the form of dust when exposed to flame. Can react violently with halogens, carbides, halogenates, halogenites, zinc, uranium, tin, sodium, lithium, nickel, palladium, phosphorus, potassium, indum, calcium, boron, aluminum, (aluminum + niobium pentoxide), ammonia, ammonium nitrate, ammonium perchlorate, BrF5, BrF3, (Ca + VO + H20), Ca(OCl)2, Cad%, Cs3N, charcoal, (Cu + chlorates), ClO2, Cl0, ClF3, CrO3, Cr(OCl)2, hydrocarbons, IF5,IO5, Pb02, Hg(NO3)2, HgO, Hg20, NO2, P2O3, (KNO3 + As2S3), K3N, KMn04, AgNO3, Ag20, NaH, (NaNO3 + charcoal), (Na + SnI4), SCl2, T12O3, F2. Can react with oxidzing materials. To fight fire, use water or special mixtures of dry chemical. When heated it burns and emits highly toxic fumes of SOX. See also NUISANCE DUSTS.
Purification Methods
Murphy, Clabaugh & Gilchrist [J Res Nat Bur Stand 64A 355 1960] have obtained sulfur of about 99.999% purity by the following procedure: Roll sulfur was melted and filtered through a coarse-porosity glass filter funnel into a 2L round-bottomed Pyrex flask with two necks. Conc H2SO4 (300mL) was added to the sulfur (2.5kg), and the mixture was heated to 150o, stirring continuously for 2hours. Over the next 6hours, conc HNO3 was added in about 2mL portions at 10-15minutes intervals to the heated mixture. It was then allowed to cool to room temperature and the acid was poured off. The sulfur was rinsed several times with distilled water, then remelted, cooled, and rinsed several times with distilled water again, this process being repeated four or five times to remove most of the acid entrapped in the sulfur. An air-cooled reflux tube (ca 40cm long) was attached to one of the necks of the flask, and a gas delivery tube (the lower end about 2.5cm above the bottom of the flask) was inserted into the other. While the sulfur was boiled under reflux, a stream of helium or N2 was passed through to remove any water, HNO3 or H2SO4, as vapours. After 4hours, the sulfur was cooled so that the reflux tube could be replaced by a bent air-cooled condenser. The sulfur was then distilled, rejecting the first and the final 100mL portions, and transferred in 200mL portions to 400mL glass cylinder ampoules (which were placed on their sides during solidification). After adding about 80mL of water, displacing the air with N2, the ampoule was cooled, and the water was titrated with 0.02M NaOH, the process being repeated until the acid content was negligible. Finally, entrapped water was removed by alternate evacuation to 10mm Hg and refilling with N2 while the sulfur was kept molten. The ampoules were then sealed. Other purifications include crystallisation from CS2 (which is less satisfactory because the sulfur retains appreciable amounts of organic material), *benzene or *benzene/acetone, followed by melting and degassing. It has also been boiled with 1% MgO, then decanted, and dried under a vacuum at 40o for 2days over P2O5. [For the purification of S6, “recrystallised S8” and “Bacon-Fanelli sulfur” see Bartlett et al. J Am Chem Soc 83 103, 109 1961.]
References
https://en.wikipedia.org/wiki/Sulfur#Applications
http://geology.com/minerals/sulfur.shtml
http://www.wisegeek.org/what-is-sulfur.htm
Check Digit Verification of cas no
The CAS Registry Mumber 7704-34-9 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 7,7,0 and 4 respectively; the second part has 2 digits, 3 and 4 respectively.
Calculate Digit Verification of CAS Registry Number 7704-34:
(6*7)+(5*7)+(4*0)+(3*4)+(2*3)+(1*4)=99
99 % 10 = 9
So 7704-34-9 is a valid CAS Registry Number.
InChI:InChI=1/S
7704-34-9Relevant articles and documents
EFFECT OF PREADSORBED SULFUR ON NITRIC OXIDE REDUCTION ON POROUS PLATINUM BLACK ELECTRODES.
Foral,Langer
, p. 257 - 263 (1988)
Sulfur can be deposited on porous platinum black gas diffusion cathodes to influence the course of the electrogenerative reduction of nitric oxide. Polarization (performance) curves and reactor selectivity data are compared for untreated cathodes and thos
Decoration of sulfur with porous metal nanostructures: An alternative strategy for improving the cyclability of sulfur cathode materials for advanced lithium-sulfur batteries
Tao, Xinyong,Chen, Feng,Xia, Yang,Huang, Hui,Gan, Yongping,Chen, Xiaorong,Zhang, Wenkui
, p. 4513 - 4515 (2013)
Porous Pt nanostructure decorated sulfur microparticles (Pt@S) are fabricated using sulfur as the template. The Pt@S electrode shows a higher volumetric specific capacity of 520 mA h cm-3 and improved cyclability with only 15% capacity fading a
Unusual syntheses, structures, and electronic properties of compounds containing ternary, T3-type supertetrahedral M/Sn/S anions [M 5Sn(μ3-S)4(SnS4) 4]10- (M = Zn, Co)
Zimmermann, Christian,Anson, Christopher E.,Weigend, Florian,Clerac, Rodolphe,Dehnen, Stefanie
, p. 5686 - 5695 (2005)
A recently discovered series of quaternary compounds of the general type [Km(ROH)n][MxSnySez] (R = H, Me), containing ternary anions with [SnSe4]4-- coordinated transition metal centers (M = Co, Mn, Zn, Cd, Hg) has now been extended by the synthesis and characterization of the two ortho-thiostannate- coordinated species, [Na10(H2O)32][M 5Sn(μ3-S)4(SnS4) 4]·2H2O (M = Zn (1), Co (2)). The central structural motifs of compounds 1 and 2 are highly charged [M5Sn(μ 3-S)4(SnS4)4]10- anions, being the first T3-type supertetrahedral ternary anions reported to date. The exposure of single crystals of 2 to a dynamic vacuum for several hours resulted in the reversible formation of a partially dehydrated, but still monocrystalline material of the composition [Na10(H2O) 6][Co5Sn(μ3-S)4-(SnS 4)4] (3). The loss of 28 of the 34 water molecules only slightly affects the internal structure of the ternary anion in 3 and leads to a significant compacting of the crystal structure with closer linkage of the [Co5Sn5S20]10- cluster units via the Na+ cations. Magnetic measurements on 3 show that the ground state of the Co/Sn/S cluster is S = 1/2, indicating a significant antiferromagnetic coupling between the Co centers, which has also been rationalized by DFT investigations of the electronic situation in the ternary subunits of 1-3.
Kinetic regularities of recovery of metals from raw materials of industrial origin
Velikanova,Semchenko,Khentov
, p. 1470 - 1475 (2011)
Kinetics of recovery of metals from the wastes and poor ores, which contain oxide and sulfide minerals of copper, vanadium, and silver with an azomethine solution in organic solvent was studied. The optimal parameters of the recovery were suggested.
Platinum-based electrocatalysts for generation of hydrogen peroxide in aqueous acidic electrolytes. Rotating ring-disk studies
Mo, Yibo,Scherson, Daniel A.
, p. E39-E46 (2003)
The electrocatalytic activity of selenium-, and sulfur-modified polycrystalline Pt electrodes for O2 reduction in acid media has been examined using rotating ring-disk electrode techniques. The results obtained indicated that, within a rather narrow range of coverages, both Se-, and S-modified Pt surfaces promote O2 reduction via a two-electron pathway to yield hydrogen peroxide at close to 100% faradaic efficiency over a wide potential region. Also presented in this work is an experimental procedure for Se-modification of high area, unsupported Pt particles based on fluidized packed bed reactor principles. Such a strategy could be readily scaled up opening new prospects for the development of large scale hydrogen peroxide generation in acid media, including electrochemically based, room temperature, Nafion-based oxygen concentrators.
The Dissociation Rate of S2 Produced from COS Pyrolysis
Higashihara, Tetsuo,Saito, Ko,Murakami, Ichiro
, p. 15 - 18 (1980)
The disappearance rate of S2, which was produced from the pyrolysis of COS, was measured behind incident shock waves by monitoring the UV emission in the temperature range of 4500-6000 K and in the pressure range of 0.32-0.5 atm.It was found that two proc
Infrared studies of the adsorption and surface reactions of hydrogen sulfide and sulfur dioxide on some aluminas and zeolites
Deo,Lana, I.G.Dalla,Habgood
, p. 270 - 281 (1971)
Adsorption of hydrogen sulfide, sulfur dioxide, and their mixtures on four different catalysts has been studied by infrared spectroscopy of the catalyst surfaces. The four catalysts, which show a wide range of acidity and are all active for the Claus reaction (2H2S + SO2 → 3S + 2H2O), were γ-alumina (the main constituent of commercial bauxite catalysts), γ-alumina doped with NaOH, sodium Y zeolite, and hydrogen Y zeolite. All catalysts showed physical adsorption of both reactants with strong hydrogen bonding to surface OH groups. This would suggest that the role of the catalyst is primarily to bring the reactants together in suitable orientation. On the other hand, γ-alumina shows, on heating with SO2, a chemisorbed SO2 species which may be a reaction intermediate. The NaOH-treated γ-alumina shows a second chemisorbed SO2 species which is irreversibly adsorbed and thus may be a catalyst poison.
Properties of a new nanosized tin sulphide phase obtained by mechanochemical route
Balaz,Takacs,Ohtani,Mack,Boldizarova,Soika,Achimovicova
, p. 76 - 82 (2002)
The paper deals with the properties of a new 4H-SnS2 phase (N-phase) synthesized together with berndtite 4H-SnS2 by a mechanochemical route from elemental tin and sulphur. The surface and bulk properties of SnS2 phases were verified by surface area measurements, particle size analysis, electron microscopy, XRD, M?ssbauer spectroscopy and chemical dissolution methods. The particles of synthesized product are 12-18 nm in size and during milling, secondary particles (aggregates) are formed that are 20-60 μm in size. The particle size and a high developed surface area (7-21 m2 g-1) greatly influence the solid-liquid reaction and solid transformations of mechanosynthesized tin sulphide products.
Preparation of MoS2 by a novel mechanochemical method
Wu, Zhuangzhi,Wang, Dezhi,Sun, Aokui
, p. L5-L7 (2010)
A novel simple process for preparing MoS2 by a mechanochemical route under the normal temperature and pressure has been developed. In this method, the mechanochemical solid-state reaction was completed in a high-energy planetary ball mill filled with pure argon. The effects of milling time and speed were discussed and the product was characterized by XRD, DSC and TEM. It is found that the as-obtained samples are MoS2 with short low stacked layers less than 10 nm, which have potential application in the highly active catalysts. Crown Copyright
Carbon nanofiber-sulfur composite cathode materials with different binders for secondary Li/S cells
Rao, Mumin,Song, Xiangyun,Liao, Honggang,Cairns, Elton J.
, p. 228 - 233 (2012)
A sulfur-coated carbon nanofiber (CNF-S) composite cathode material was prepared by a chemical deposition method in an aqueous solution. This CNF-S material was evaluated as the cathode material in lithium/sulfur cells with three different binders. The results of the SEM and TGA measurements reveal that CNF-S has a typical core-shell structure, containing 75.7 w/o sulfur coated uniformly on the surface of the CNFs. The effects of different binders on the potential profiles, electrode capacity and capacity retention with cycling were investigated. The electrode prepared with CMC + SBR binder has the best performance compared with PVdF and PEO binders, exhibiting a specific capacity of up to 1313 mAh g-1 S at the initial discharge and a specific capacity of 586 mAh g-1 S after 60 cycles.