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{{chembox
{| class="toccolours" border="1" style="float: right; clear: right; margin: 0 0 1em 1em; border-collapse: collapse;"
|Verifiedfields = changed
! {{chembox header}} | Molybdenum disulfide <!-- replace if not identical with the article name -->
|Watchedfields = changed
|-
|verifiedrevid = 444652607
| align="center" colspan="2" bgcolor="#ffffff" | [[Image:Molybdenum disulfide.jpg|200px|Molybdenum disulfide]] <!-- replace if not identical with the pagename -->
|Name = Molybdenum disulfide
|-
|ImageFile = MoS2chips.jpg
! {{chembox header}} | General
|ImageFile2 = Molybdenite-3D-balls.png
|-
|ImageName = Molybdenum disulfide
| [[IUPAC nomenclature|Systematic name]]
| Molybdenum disulfide<br/>Molybdenum(IV) sulfide
|IUPACName = Molybdenum disulfide
|OtherNames = Molybdenum(IV) sulfide
|-
|Section1={{Chembox Identifiers
| Other names
|ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| [[Molybdenite]]
|ChemSpiderID = 14138
|-
|InChI = 1/Mo.2S/rMoS2/c2-1-3
| [[Chemical formula|Molecular formula]]
|InChIKey = CWQXQMHSOZUFJS-FRBXWHJUAU
| MoS<sub>2</sub>
|ChEBI_Ref = {{ebicite|correct|EBI}}
|-
|ChEBI = 30704
| [[Molar mass]]
|SMILES = S=[Mo]=S
| 160.07 g/mol
|StdInChI_Ref = {{stdinchicite|correct|chemspider}}
|-
|StdInChI = 1S/Mo.2S
| Appearance
|StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| black solid
|StdInChIKey = CWQXQMHSOZUFJS-UHFFFAOYSA-N
|-
|CASNo = 1317-33-5
| [[CAS registry number|CAS number]]
|CASNo_Ref = {{cascite|correct|CAS}}
| <!--{{CASREF|CAS=-->1317-33-5
|UNII_Ref = {{fdacite|correct|FDA}}
|-
|UNII = ZC8B4P503V
! {{chembox header}} | Properties
|RTECS = QA4697000
|-
|PubChem = 14823
| [[Density]] and [[Phase (matter)|phase]]
}}
| 5.06 g/cm³, ? <!-- ? g/cm³, solid / ? g/ml, liquid / ? g/l, gas -->
|Section2={{Chembox Properties
|-
|Mo=1|S=2
| [[Soluble|Solubility]]
|Appearance = black/lead-gray solid
| insoluble in all solvents
|Density = 5.06 g/cm<sup>3</sup><ref name=b92>{{RubberBible92nd|page=4.76}}</ref>
|-
|MeltingPtC = 2375
| [[Melting point]]
|MeltingPt_ref = <ref name="PubChemMoS2">{{cite web |url=https://pubchem.ncbi.nlm.nih.gov/compound/14823#section=Color |title=Molybdenum Disulfide |publisher=PubChem |access-date=August 31, 2018}}</ref>
| 1185 °C ''decomp.''
|Solubility = insoluble<ref name=b92/>
|-
|SolubleOther = decomposed by [[aqua regia]], hot [[sulfuric acid]], [[nitric acid]] <br> insoluble in dilute acids
! {{chembox header}} | Structure
|BandGap = 1.23 eV (indirect, 3R or 2H bulk)<ref name=band>{{Cite journal | doi = 10.1103/PhysRevB.51.17085| pmid = 9978722| title = Electronic structure and scanning-tunneling-microscopy image of molybdenum dichalcogenide surfaces| journal = Physical Review B| volume = 51| issue = 23| pages = 17085–17095| year = 1995| last1 = Kobayashi | first1 = K. | last2 = Yamauchi | first2 = J. | bibcode = 1995PhRvB..5117085K}}</ref><br>~1.8 eV (direct, monolayer)<ref>{{cite journal|doi=10.1103/PhysRevB.85.033305|title=Thickness and strain effects on electronic structures of transition metal dichalcogenides: 2H-''MX''<sub>2</sub> semiconductors (''M'' = Mo, W; ''X'' = S, Se, Te)|journal=Physical Review B|volume=85|issue=3|pages=033305|year=2012|last1=Yun|first1=Won Seok|last2=Han|first2=S. W.|last3=Hong|first3=Soon Cheol|last4=Kim|first4=In Gee|last5=Lee|first5=J. D.|bibcode=2012PhRvB..85c3305Y}}</ref>
|-
}}
| [[Coordination geometry|Coordination<br/>geometry]]
|Section3={{Chembox Structure
| [[Trigonal prism]]atic at Mo,
|CrystalStruct = [[Pearson symbol|hP6]], [[space group|{{chem|P6|3}}/mmc]], No. 194 (2H)<br>
pyramidal at S
[[Pearson symbol|hR9]], [[space group|R3m]], No 160 (3R)<ref name=str>{{Cite journal | doi = 10.1107/S0108768183002645| title = Anisotropic mean-square displacements (MSD) in single-crystals of 2H- and 3R-MoS<sub>2</sub>| journal = Acta Crystallographica Section B| volume = 39| issue = 4| pages = 404–407| year = 1983| last1 = Schönfeld | first1 = B.| last2 = Huang | first2 = J. J.| last3 = Moss | first3 = S. C.| doi-access = free| bibcode = 1983AcCrB..39..404S}}</ref>
|-
|LattConst_a = 0.3161 nm (2H), 0.3163 nm (3R)
| [[Crystal structure]]
|LattConst_c = 1.2295 nm (2H), 1.837 (3R)
| ''see text''
|Coordination = [[Trigonal prism]]atic ({{chem2|Mo^{IV}|}})<br/>Pyramidal ({{chem2|S(2−)}})
|-
}}
! {{chembox header}} | Hazards
|Section5={{Chembox Thermochemistry
|-
|DeltaHf = −235.10 kJ/mol
| [[Material safety data sheet|MSDS]]
|DeltaGf = −225.89 kJ/mol
| [[Molybdenum disulfide (data page)#Material Safety Data Sheet|External MSDS]] <!-- please replace with proper link-->
|Entropy = 62.63 J/(mol·K)
|-
}}
| [[Directive 67/548/EEC|EU classification]]
|Section7={{Chembox Hazards
| not listed
|ExternalSDS = [https://www.acsmaterial.com/pub/media/catalog/product/s/d/sds-molybdenum_disulfide.pdf External MSDS]
|-
}}
| [[NFPA 704]]
|Section8={{Chembox Related
| <!-- {{nfpa|4|4 ox|4}} These are set on "very dangerous" as default- adjust according to actual values -->
|OtherAnions = [[Molybdenum(IV) oxide]] <br/> [[Molybdenum diselenide]] <br/> [[Molybdenum ditelluride]]
|-
|OtherCations = [[Tungsten disulfide]]
| [[Flash point]]
|OtherFunction = [[Graphite]]
| n.a.
|OtherFunction_label = [[lubricant]]s
|-
}}
| [[RTECS]] number
}}
| QA4697000
{{Redirect-distinguish|Molybdenum sulfide|Molybdenum trisulfide}}
|-
! {{chembox header}} | [[Molybdenum disulfide (data page)|Supplementary data page]]
|-
| [[Molybdenum disulfide (data page)#Structure and properties|Structure and<br/>properties]]
| [[Refractive index|''n'']], [[Dielectric constant|ε<sub>r</sub>]], etc.
|-
| [[Molybdenum disulfide (data page)#Thermodynamic properties|Thermodynamic<br/>data]]
| Phase behaviour<br>Solid, liquid, gas
|-
| [[Molybdenum disulfide (data page)#Spectral data|Spectral data]]
| [[UV/VIS spectroscopy|UV]], [[Infrared spectroscopy|IR]], [[NMR spectroscopy|NMR]], [[Mass spectrometry|MS]]
|-
! {{chembox header}} | Related compounds
|-
| Other [[Ion|anion]]s
| [[Molybdenum(IV) oxide]]<br/>[[Molybdenum trioxide]]
|-
| Other [[Ion|cation]]s
| [[Tungsten disulfide]]
|-
| Related [[lubricant]]s
| [[Graphite]]
|-
| {{chembox header}} | <small>Except where noted otherwise, data are given for<br> materials in their [[standard state|standard state (at 25 °C, 100 kPa)]]<br/>[[wikipedia:Chemical infobox|Infobox disclaimer and references]]</small>
|-
|}


'''Molybdenum disulfide''' (or moly) is an [[inorganic chemistry|inorganic compound]] composed of [[molybdenum]] and [[sulfur]]. Its [[chemical formula]] is '''{{chem2|MoS2}}'''.
'''Molybdenum disulfide''', also called '''molybdenum sulfide''' or '''molybdenum(IV) sulfide''', with the formula '''MoS<sub>2</sub>''', is a black crystalline [[sulfide]] of [[molybdenum]] and one of several compounds known as [[transition metal dichalcogenides]]. It occurs as the mineral [[molybdenite]]. It is insoluble in [[water]] and unreactive toward dilute [[acid]]s. Its melting point is 1185 °C, but it starts [[aerobic|oxidizing in air]] from 315 °C, limiting the range of its use as a [[lubricant]] in the presence of air between the temperatures of -185 and +350 °C; in [[Hypoxia (environmental)|nonoxidizing]] environments it is stable up to 1100 °C.[http://www.a-m.de/englisch/lexikon/molybdaendisulfid.htm]


The compound is classified as a [[transition metal dichalcogenide]]. It is a silvery black solid that occurs as the mineral [[molybdenite]], the principal ore for molybdenum.<ref name=ullmann>Sebenik, Roger F. ''et al''. (2005) "Molybdenum and Molybdenum Compounds", ''Ullmann's Encyclopedia of Chemical Technology''. Wiley-VCH, Weinheim. {{doi| 10.1002/14356007.a16_655}}</ref> {{chem2|MoS2}} is relatively unreactive. It is unaffected by dilute [[acid]]s and [[oxygen]]. In appearance and feel, molybdenum disulfide is similar to [[graphite]]. It is widely used as a [[dry lubricant]] because of its low [[friction]] and robustness. Bulk {{chem2|MoS2}} is a [[Diamagnetism|diamagnetic]], [[indirect bandgap]] semiconductor similar to [[silicon]], with a bandgap of 1.23 eV.<ref name=band/>
==Use as Lubricant==
The structure, appearance, and feel of molybdenum disulfide is similar to [[graphite]] - a sandwich of layers of molybdenum atoms between the layers of sulfur atoms. Due to the weak interactions between the sheets of sulfide atoms, MoS<sub>2</sub> has a low [[coefficient of friction]] resulting in a lubricating effect. Finely powdered MoS<sub>2</sub> with particle sizes in the range of 1-100 µ[[metre|m]] is a common dry lubricant. It is also often mixed into various [[oil]]s and [[grease (lubricant)|grease]]s, which allows the mechanisms lubricated by it to keep running for a while longer, even in cases of almost complete oil loss - finding an important use in [[aircraft engine]]s. It is often used in motorcycle engines, especially in areas of [[two-stroke engine]]s which are not otherwise well lubricated.


== Production ==
MoS<sub>2</sub> grease is recommended for [[Constant-velocity joint|CV]] and [[universal joint]]s.
[[File:Molly Hill molybdenite.JPG|thumb|left|Molybdenite]]{{chem2|MoS2}} is naturally found as either [[molybdenite]], a crystalline mineral, or jordisite, a rare low temperature form of molybdenite.<ref>{{Cite web|url=https://www.mindat.org/min-2114.html|title=Jordisite|website=www.mindat.org}}</ref> Molybdenite ore is processed by [[Froth flotation|flotation]] to give relatively pure {{chem2|MoS2}}. The main contaminant is carbon. {{chem2|MoS2}} also arises by thermal treatment of virtually all molybdenum compounds with [[hydrogen sulfide]] or elemental sulfur and can be produced by metathesis reactions from [[molybdenum pentachloride]].<ref>{{cite book | author= Murphy, Donald W. |author2= Interrante, Leonard V. | year = 1995 | title = Inorganic Syntheses | volume = 30 | pages = 33–37 | doi = 10.1002/9780470132616.ch8 |last3= Kaner |last4= Mansuktto |chapter= Metathetical Precursor Route to Molybdenum Disulfide |isbn= 9780470132616}}</ref>
<!-- Add a section about the mechanism of work, why it is so good, how it smooths the roughness on the parts by reacting with its surface under high pressure, forming softer metal sulfides and then abrading them -->


== Structure and physical properties ==
It is also used as a lubricating additive to special [[plastic]]s, notably [[nylon]] and [[Teflon]]. <!-- Saw them in a Farnell catalog. -->
[[File:MoS2 antisites&vacancies.jpg|thumb|left|Electron microscopy of antisites (a, Mo substitutes for S) and vacancies (b, missing S atoms) in a [[monolayer]] of molybdenum disulfide. Scale bar: 1 nm.<ref>{{Cite journal | doi = 10.1038/ncomms7293| pmid = 25695374| pmc = 4346634| title = Exploring atomic defects in molybdenum disulphide monolayers| journal = [[Nature Communications]]| volume = 6| pages = 6293| year = 2015| last1 = Hong | first1 = J. | last2 = Hu | first2 = Z. | last3 = Probert | first3 = M. | last4 = Li | first4 = K. | last5 = Lv | first5 = D. | last6 = Yang | first6 = X. | last7 = Gu | first7 = L. | last8 = Mao | first8 = N. | last9 = Feng | first9 = Q. | last10 = Xie | first10 = L. | last11 = Zhang | first11 = J. | last12 = Wu | first12 = D. | last13 = Zhang | first13 = Z. | last14 = Jin | first14 = C. | last15 = Ji | first15 = W. | last16 = Zhang | first16 = X. | last17 = Yuan | first17 = J. | last18 = Zhang | first18 = Z. | bibcode = 2015NatCo...6.6293H}}</ref>]]


=== Crystalline phases ===
During the [[Vietnam war]], a commercial molybdenum disulfide product, "Dri-Slide", was used for lubricating troops' weapons; the military refused to supply it, as it was "not in the manual", so it was sent to soldiers by their parents and friends privately.<!---Dri-Slide was not moly, it was PTFE. Moly is dark like graphite and the Dri-Slide is off-white. --->[http://mmd.foxtail.com/Archives/Digests/199809/1998.09.05.09.html]
All forms of {{chem2|MoS2}} have a layered structure, in which a plane of molybdenum atoms is sandwiched by planes of sulfide ions. These three strata form a monolayer of {{chem2|MoS2}}. Bulk {{chem2|MoS2}} consists of stacked monolayers, which are held together by weak [[van der Waals interactions]].
Another application is for coating [[bullet]]s, giving them easier passage through the rifle barrel with less deformation and better ballistic accuracy.


Crystalline {{chem2|MoS2}} exists in one of two phases, 2H-{{chem2|MoS2}} and 3R-{{chem2|MoS2}}, where the "H" and the "R" indicate hexagonal and rhombohedral symmetry, respectively. In both of these structures, each molybdenum atom exists at the center of a [[trigonal prism]]atic [[coordination sphere]] and is covalently bonded to six sulfide ions. Each sulfur atom has pyramidal coordination and is bonded to three molybdenum atoms. Both the 2H- and 3R-phases are semiconducting.<ref>{{Cite book|url=https://www.springer.com/series/562|title=Gmelin Handbook of Inorganic and Organometallic Chemistry - 8th edition|language=de}}</ref>
Self-lubricating composite coatings for high temperature applications were developed at the [[Oak Ridge National Laboratory]]. A composite coating of molybdenum disulfide and [[titanium nitride]] was created on the surface of parts by [[chemical vapor deposition]]. [http://www.ornl.gov/info/press_releases/get_press_release.cfm?ReleaseNumber=mr19950329-01]


A third, metastable crystalline phase known as 1T-{{chem2|MoS2}} was discovered by intercalating 2H-{{chem2|MoS2}} with [[alkali metals]].<ref>{{Cite journal|last1=Wypych|first1=Fernando|last2=Schöllhorn|first2=Robert|date=1992-01-01|title=1T-MoS2, a new metallic modification of molybdenum disulfide|url=http://pubs.rsc.org/is/content/articlehtml/1992/c3/c39920001386|journal=Journal of the Chemical Society, Chemical Communications|language=en|issue=19|pages=1386–1388|doi=10.1039/C39920001386|issn=0022-4936}}</ref> This phase has trigonal symmetry and is metallic. The 1T-phase can be stabilized through doping with electron donors such as [[rhenium]],<ref>{{Cite journal|last1=Enyashin|first1=Andrey N.|last2=Yadgarov|first2=Lena|last3=Houben|first3=Lothar|last4=Popov|first4=Igor|last5=Weidenbach|first5=Marc|last6=Tenne|first6=Reshef|last7=Bar-Sadan|first7=Maya|last8=Seifert|first8=Gotthard|date=2011-12-22|title=New Route for Stabilization of 1T-WS2 and MoS2 Phases|journal=The Journal of Physical Chemistry C|volume=115|issue=50|pages=24586–24591|doi=10.1021/jp2076325|issn=1932-7447|arxiv=1110.3848|s2cid=95117205}}</ref> or converted back to the 2H-phase by microwave radiation.<ref>{{Cite journal|last1=Xu|first1=Danyun|last2=Zhu|first2=Yuanzhi|last3=Liu|first3=Jiapeng|last4=Li|first4=Yang|last5=Peng|first5=Wenchao|last6=Zhang|first6=Guoliang|last7=Zhang|first7=Fengbao|last8=Fan|first8=Xiaobin|date=2016|title=Microwave-assisted 1T to 2H phase reversion of MoS 2 in solution: a fast route to processable dispersions of 2H-MoS 2 nanosheets and nanocomposites|journal=Nanotechnology|language=en|volume=27|issue=38|pages=385604|doi=10.1088/0957-4484/27/38/385604|pmid=27528593|issn=0957-4484|bibcode=2016Nanot..27L5604X|s2cid=23849142}}</ref> The 2H/1T-phase transition can be controlled via the incorporation of sulfur (S) [[Vacancy defect|vacancies]].<ref>{{Cite journal |last1=Gan |first1=Xiaorong |last2=Lee |first2=Lawrence Yoon Suk |last3=Wong |first3=Kwok-yin |last4=Lo |first4=Tsz Wing |last5=Ho |first5=Kwun Hei |last6=Lei |first6=Dang Yuan |last7=Zhao |first7=Huimin |date=2018-09-24 |title=2H/1T Phase Transition of Multilayer MoS 2 by Electrochemical Incorporation of S Vacancies |url=https://pubs.acs.org/doi/10.1021/acsaem.8b00875 |journal=ACS Applied Energy Materials |language=en |volume=1 |issue=9 |pages=4754–4765 |doi=10.1021/acsaem.8b00875 |s2cid=106014720 |issn=2574-0962}}</ref>
==Use in [[Petrochemistry]]==
Synthetic MoS<sub><small>2</small></sub> is employed as a [[catalyst]] for desulfurization in petroleum refineries, e.g. [[hydrodesulfurization]]. The effectiveness of the MoS<sub><small>2</small></sub> catalysts is enhanced by doping with small amounts of cobalt and the intimate mixture is supported on alumina. Such catalysts are generated in situ by treating molybdate/cobalt-impregnated alumina with H<sub><small>2</small></sub>S or an equivalent reagent.


==References==
===Allotropes===
[[Carbon nanotube|Nanotube]]-like and [[buckyball]]-like molecules composed of {{chem2|MoS2}} are known.<ref>{{Cite journal | doi = 10.1039/B901466G| pmid = 20419198| title = Recent progress in the research of inorganic fullerene-like nanoparticles and inorganic nanotubes| journal = Chemical Society Reviews| volume = 39| issue = 5| pages = 1423–34| year = 2010| last1 = Tenne | first1 = R. | last2 = Redlich | first2 = M.}}</ref>
* Topsøe, H.; Clausen, B. S.; Massoth, F. E. "Hydrotreating Catalysis, Science and Technology"; Springer-Verlag: Berlin, 1996.


===Exfoliated {{chem2|MoS2}} flakes===
==External links==
While bulk {{chem2|MoS2}} in the 2H-phase is known to be an indirect-band gap semiconductor, monolayer {{chem2|MoS2}} has a direct band gap. The layer-dependent optoelectronic properties of {{chem2|MoS2}} have promoted much research in 2-dimensional {{chem2|MoS2}}-based devices. 2D {{chem2|MoS2}} can be produced by exfoliating bulk crystals to produce single-layer to few-layer flakes either through a dry, micromechanical process or through solution processing.
* [http://www.gfschemicals.com/Search/MSDS/1468MSDS.PDF Molybdenum sulfide MSDS]


Micromechanical exfoliation, also pragmatically called "[[Graphene production techniques#Adhesive tape|Scotch-tape exfoliation]]", involves using an adhesive material to repeatedly peel apart a layered crystal by overcoming the van der Waals forces. The crystal flakes can then be transferred from the adhesive film to a substrate. This facile method was first used by [[Konstantin Novoselov]] and [[Andre Geim]] to obtain graphene from graphite crystals. However, it can not be employed for a uniform 1-D layers because of weaker adhesion of {{chem2|MoS2}} to the substrate (either silicon, glass or quartz); the aforementioned scheme is good for graphene only.<ref>{{Cite journal|last1=Novoselov|first1=K. S.|last2=Geim|first2=A. K.|last3=Morozov|first3=S. V.|last4=Jiang|first4=D.|last5=Zhang|first5=Y.|last6=Dubonos|first6=S. V.|last7=Grigorieva|first7=I. V.|last8=Firsov|first8=A. A.|date=2004-10-22|title=Electric Field Effect in Atomically Thin Carbon Films|journal=Science|language=en|volume=306|issue=5696|pages=666–669|doi=10.1126/science.1102896|issn=0036-8075|pmid=15499015|bibcode=2004Sci...306..666N|arxiv=cond-mat/0410550|s2cid=5729649}}</ref> While Scotch tape is generally used as the adhesive tape, [[Polydimethylsiloxane|PDMS]] stamps can also satisfactorily cleave {{chem2|MoS2}} if it is important to avoid contaminating the flakes with residual adhesive.<ref name="Castellanos-Gomez-2012">{{Cite journal|last1=Castellanos-Gomez|first1=Andres|last2=Poot|first2=Menno|last3=Steele|first3=Gary A.|last4=van der Zant|first4=Herre S. J.|last5=Agraït|first5=Nicolás|last6=Rubio-Bollinger|first6=Gabino|date=2012-02-07|title=Elastic Properties of Freely Suspended MoS2 Nanosheets|journal=Advanced Materials|language=en|volume=24|issue=6|pages=772–775|doi=10.1002/adma.201103965|pmid=22231284|issn=1521-4095|arxiv=1202.4439|bibcode=2012AdM....24..772C |s2cid=205243099}}</ref>
{{ChemicalSources}}


Liquid-phase exfoliation can also be used to produce monolayer to multi-layer {{chem2|MoS2}} in solution. A few methods include lithium [[Intercalation (chemistry)|intercalation]]<ref>{{Cite journal|last1=Wan|first1=Jiayu|last2=Lacey|first2=Steven D.|last3=Dai|first3=Jiaqi|last4=Bao|first4=Wenzhong|last5=Fuhrer|first5=Michael S.|last6=Hu|first6=Liangbing|date=2016-12-05|title=Tuning two-dimensional nanomaterials by intercalation: materials, properties and applications|journal=Chemical Society Reviews|language=en|volume=45|issue=24|pages=6742–6765|doi=10.1039/C5CS00758E|pmid=27704060|issn=1460-4744}}</ref> to delaminate the layers and [[sonication]] in a high-surface tension solvent.<ref>{{Cite journal|last1=Coleman|first1=Jonathan N.|last2=Lotya|first2=Mustafa|last3=O’Neill|first3=Arlene|last4=Bergin|first4=Shane D.|last5=King|first5=Paul J.|last6=Khan|first6=Umar|last7=Young|first7=Karen|last8=Gaucher|first8=Alexandre|last9=De|first9=Sukanta|date=2011-02-04|title=Two-Dimensional Nanosheets Produced by Liquid Exfoliation of Layered Materials|journal=Science|language=en|volume=331|issue=6017|pages=568–571|doi=10.1126/science.1194975|issn=0036-8075|pmid=21292974|bibcode=2011Sci...331..568C|hdl=2262/66458|s2cid=23576676 |hdl-access=free}}</ref><ref>{{Cite journal|last1=Zhou|first1=Kai-Ge|last2=Mao|first2=Nan-Nan|last3=Wang|first3=Hang-Xing|last4=Peng|first4=Yong|last5=Zhang|first5=Hao-Li|date=2011-11-11|title=A Mixed-Solvent Strategy for Efficient Exfoliation of Inorganic Graphene Analogues|journal=Angewandte Chemie|language=en|volume=123|issue=46|pages=11031–11034|doi=10.1002/ange.201105364|bibcode=2011AngCh.12311031Z |issn=1521-3757}}</ref>
[[Category:Molybdenum compounds]]
[[Category:Sulfides]]
[[Category:Lubricants]]
[[Category:Semiconductor materials]]


=== Mechanical properties ===
[[de:Molybdändisulfid]]
{{chem2|MoS2}} excels as a lubricating material (see below) due to its layered structure and low [[Friction|coefficient of friction]]. Interlayer sliding dissipates energy when a shear stress is applied to the material. Extensive work has been performed to characterize the coefficient of friction and shear strength of {{chem2|MoS2}} in various atmospheres.<ref name="Donnet-1996">{{Cite journal|last1=Donnet|first1=C.|last2=Martin|first2=J. M.|last3=Le Mogne|first3=Th.|last4=Belin|first4=M.|date=1996-02-01|title=Super-low friction of MoS2 coatings in various environments|journal=Tribology International|volume=29|issue=2|pages=123–128|doi=10.1016/0301-679X(95)00094-K}}</ref> The [[shear strength]] of {{chem2|MoS2}} increases as the coefficient of friction increases. This property is called [[superlubricity]]. At ambient conditions, the coefficient of friction for {{chem2|MoS2}} was determined to be 0.150, with a corresponding estimated shear strength of 56.0 MPa.<ref name="Donnet-1996" /> Direct methods of measuring the shear strength indicate that the value is closer to 25.3 MPa.<ref>{{Cite journal|last1=Oviedo|first1=Juan Pablo|last2=KC|first2=Santosh|last3=Lu|first3=Ning|last4=Wang|first4=Jinguo|last5=Cho|first5=Kyeongjae|last6=Wallace|first6=Robert M.|last7=Kim|first7=Moon J.|date=2015-02-24|title=In Situ TEM Characterization of Shear-Stress-Induced Interlayer Sliding in the Cross Section View of Molybdenum Disulfide|journal=ACS Nano|volume=9|issue=2|pages=1543–1551|doi=10.1021/nn506052d|pmid=25494557|issn=1936-0851}}</ref>
[[ja:二硫化モリブデン]]

The wear resistance of {{chem2|MoS2}} in lubricating applications can be increased by [[Doping (semiconductor)|doping]] {{chem2|MoS2}} with [[chromium|Cr]]. Microindentation experiments on [[nanopillar]]s of Cr-doped {{chem2|MoS2}} found that the yield strength increased from an average of 821 MPa for pure {{chem2|MoS2}} (at 0% Cr) to 1017 MPa at 50% Cr.<ref name="Tedstone-2015">{{Cite journal|last1=Tedstone|first1=Aleksander A.|last2=Lewis|first2=David J.|last3=Hao|first3=Rui|last4=Mao|first4=Shi-Min|last5=Bellon|first5=Pascal|last6=Averback|first6=Robert S.|last7=Warrens|first7=Christopher P.|last8=West|first8=Kevin R.|last9=Howard|first9=Philip|date=2015-09-23|title=Mechanical Properties of Molybdenum Disulfide and the Effect of Doping: An in Situ TEM Study|journal=ACS Applied Materials & Interfaces|volume=7|issue=37|pages=20829–20834|doi=10.1021/acsami.5b06055|pmid=26322958|issn=1944-8244|doi-access=free}}</ref> The increase in yield strength is accompanied by a change in the failure mode of the material. While the pure {{chem2|MoS2}} nanopillar fails through a plastic bending mechanism, brittle fracture modes become apparent as the material is loaded with increasing amounts of dopant.<ref name="Tedstone-2015"/>

The widely used method of micromechanical exfoliation has been carefully studied in {{chem2|MoS2}} to understand the mechanism of delamination in few-layer to multi-layer flakes. The exact mechanism of cleavage was found to be layer dependent. Flakes thinner than 5 layers undergo homogenous bending and rippling, while flakes around 10 layers thick delaminated through interlayer sliding. Flakes with more than 20 layers exhibited a kinking mechanism during micromechanical cleavage. The cleavage of these flakes was also determined to be reversible due to the nature of van der Waals bonding.<ref>{{Cite journal|last1=Tang|first1=Dai-Ming|last2=Kvashnin|first2=Dmitry G.|last3=Najmaei|first3=Sina|last4=Bando|first4=Yoshio|last5=Kimoto|first5=Koji|last6=Koskinen|first6=Pekka|last7=Ajayan|first7=Pulickel M.|last8=Yakobson|first8=Boris I.|last9=Sorokin|first9=Pavel B.|date=2014-04-03|title=Nanomechanical cleavage of molybdenum disulphide atomic layers|journal=Nature Communications|language=en|volume=5|pages=3631|doi=10.1038/ncomms4631|pmid=24698887|bibcode=2014NatCo...5.3631T|doi-access=free}}</ref>

In recent years, {{chem2|MoS2}} has been utilized in flexible electronic applications, promoting more investigation into the elastic properties of this material. Nanoscopic bending tests using [[Atomic-force microscopy|AFM]] cantilever tips were performed on micromechanically exfoliated {{chem2|MoS2}} flakes that were deposited on a holey substrate.<ref name="Castellanos-Gomez-2012" /><ref name="Bertolazzi-2011">{{Cite journal|last1=Bertolazzi|first1=Simone|last2=Brivio|first2=Jacopo|last3=Kis|first3=Andras|title=Stretching and Breaking of Ultrathin MoS2|journal=ACS Nano|language=en|volume=5|issue=12|pages=9703–9709|doi=10.1021/nn203879f|pmid=22087740|year=2011|url=http://infoscience.epfl.ch/record/170263}}</ref> The yield strength of monolayer flakes was 270 GPa,<ref name="Bertolazzi-2011" /> while the thicker flakes were also stiffer, with a yield strength of 330 GPa.<ref name="Castellanos-Gomez-2012" /> Molecular dynamic simulations found the in-plane yield strength of {{chem2|MoS2}} to be 229 GPa, which matches the experimental results within error.<ref>{{Cite journal|last1=Jiang|first1=Jin-Wu|last2=Park|first2=Harold S.|last3=Rabczuk|first3=Timon|date=2013-08-12|title=Molecular dynamics simulations of single-layer molybdenum disulphide (MoS2): Stillinger-Weber parametrization, mechanical properties, and thermal conductivity|journal=Journal of Applied Physics|volume=114|issue=6|pages=064307–064307–10|doi=10.1063/1.4818414|issn=0021-8979|bibcode=2013JAP...114f4307J|arxiv=1307.7072|s2cid=119304891}}</ref>

Bertolazzi and coworkers also characterized the failure modes of the suspended monolayer flakes. The strain at failure ranges from 6 to 11%. The average yield strength of monolayer {{chem2|MoS2}} is 23 GPa, which is close to the theoretical fracture strength for defect-free {{chem2|MoS2}}.<ref name="Bertolazzi-2011" />

The band structure of {{chem2|MoS2}} is sensitive to strain.<ref>{{cite journal| first1=H. | last1=Li| first2= J. | last2=Wu| first3= Z. | last3=Yin | first4=H. | last4=Zhang| title=Preparation and Applications of Mechanically Exfoliated Single-Layer and Multilayer MoS<sub>2</sub> and WSe<sub>2</sub> Nanosheets| journal= Acc. Chem. Res.| year= 2014| volume= 47| issue=4| pages= 1067–75| doi=10.1021/ar4002312| pmid=24697842}}</ref><ref>{{Cite journal|title=Novel effects of strains in graphene and other two dimensional materials|journal=Physics Reports|volume=1503|pages=1–54|doi= 10.1016/j.physrep.2015.12.006|year=2016|last1=Amorim|first1=B.|last2=Cortijo|first2=A.|last3=De Juan|first3=F.|last4=Grushin|first4=A.G.|last5=Guinea|first5=F.|last6=Gutiérrez-Rubio|first6=A.|last7=Ochoa|first7=H.|last8=Parente|first8=V.|last9=Roldán|first9=R.|last10=San-Jose|first10=P.|last11=Schiefele|first11=J.|last12=Sturla|first12=M.|last13=Vozmediano|first13=M.A.H.|bibcode=2016PhR...617....1A|arxiv=1503.00747|s2cid=118600177}}</ref><ref>{{cite journal | last1 = Zhang | first1 = X. | last2 = Lai | first2 = Z. | last3 = Tan | first3 = C. | last4 = Zhang | first4 = H. | year = 2016 | title = Solution-Processed Two-Dimensional MoS<sub>2</sub> Nanosheets: Preparation, Hybridization, and Applications | journal = Angew. Chem. Int. Ed. | volume = 55 | issue = 31| pages = 8816–8838 | doi = 10.1002/anie.201509933 | pmid = 27329783}}</ref>

== Chemical reactions ==
Molybdenum disulfide is stable in air and attacked only by aggressive [[reagent]]s. It reacts with oxygen upon heating forming [[molybdenum trioxide]]:
:{{chem2|2 MoS2 + 7 O2 → 2 MoO3 + 4 SO2}}

[[Chlorine]] attacks molybdenum disulfide at elevated temperatures to form [[molybdenum pentachloride]]:
:{{chem2|2 MoS2 + 7 Cl2 → 2 MoCl5 + 2 S2Cl2}}

===Intercalation reactions===
Molybdenum disulfide is a host for formation of [[intercalation compounds]]. This behavior is relevant to its use as a cathode material in batteries.<ref>{{cite journal | last1 = Stephenson | first1 = T. | last2 = Li | first2 = Z. | last3 = Olsen | first3 = B. | last4 = Mitlin | first4 = D. | year = 2014 | title = Lithium Ion Battery Applications of Molybdenum Disulfide (MoS<sub>2</sub>) Nanocomposites | journal = Energy Environ. Sci. | volume = 7 | pages = 209–31 | doi = 10.1039/C3EE42591F}}</ref><ref>{{cite journal | last1 = Benavente | first1 = E. | last2 = Santa Ana | first2 = M. A. | last3 = Mendizabal | first3 = F. | last4 = Gonzalez | first4 = G. | year = 2002 | title = Intercalation chemistry of molybdenum disulfide | journal = Coordination Chemistry Reviews | volume = 224 | issue = 1–2 | pages = 87–109 | doi = 10.1016/S0010-8545(01)00392-7 | hdl = 10533/173130 | hdl-access = free}}</ref> One example is a lithiated material, {{chem2|Li_{''x''}MoS2}}.<ref>{{cite book|title =Progress in intercalation research|author1=Müller-Warmuth, W. |author2=Schöllhorn, R. |name-list-style=amp | url={{Google books|id=IyB_rPo3osUC|page=50|plainurl=yes}} |publisher= Springer| year = 1994| isbn =978-0-7923-2357-0}}</ref> With [[n-Butyllithium|butyl lithium]], the product is {{chem2|LiMoS2}}.<ref name=ullmann/>

== Applications ==
=== Lubricant ===
[[File:Graphite moly.jpg|thumb|A tube of commercial graphite powder lubricant with molybdenum disulfide additive (called "molybdenum")<ref name=moly>[http://www.pinewoodpro.com/graphite-nyoil.php High Performance, Dry Powdered Graphite with sub-micron molybdenum disulfide]. pinewoodpro.com</ref>]]
Due to weak [[van der Waals force|van der Waals]] interactions between the sheets of sulfide atoms, {{chem2|MoS2}} has a low [[coefficient of friction]]. {{chem2|MoS2}} in particle sizes in the range of 1–100&nbsp;μm is a common [[dry lubricant]].<ref>{{citation| last=Claus| first= F. L. |year= 1972| title=Solid Lubricants and Self-Lubricating Solids| journal= New York: Academic Press | bibcode= 1972slsl.book.....C}}</ref> Few alternatives exist that confer high lubricity and stability at up to 350&nbsp;°C in oxidizing environments. Sliding friction tests of {{chem2|MoS2}} using a [[pin on disc tester]] at low loads (0.1–2 N) give friction coefficient values of <0.1.<ref name="MiesslerTarr2004">{{cite book|first1=Gary L. |last1=Miessler|first2=Donald Arthur|last2= Tarr|title=Inorganic Chemistry|url={{google books |plainurl=y |id=oLQPAQAAMAAJ}}|year=2004|publisher=Pearson Education|isbn=978-0-13-035471-6}}</ref><ref name="ShriverAtkins2006">{{cite book|first1=Duward |last1=Shriver|first2=Peter |last2=Atkins|title=Inorganic Chemistry|url={{google books |plainurl=y |id=so8oAQAAMAAJ}}|date=17 February 2006|publisher=W. H. Freeman|isbn=978-0-7167-4878-6| last3= Overton| first3= T. L.| last4= Rourke| first4= J. P.| last5= Weller| first5= M. T.| last6= Armstrong| first6= F. A.}}</ref>

{{chem2|MoS2}} is often a component of blends and composites that require low friction. For example, it is added to graphite to improve sticking.<ref name=moly/> A variety of [[oil]]s and [[grease (lubricant)|grease]]s are used, because they retain their lubricity even in cases of almost complete oil loss, thus finding a use in critical applications such as [[aircraft engine]]s. When added to [[plastic]]s, {{chem2|MoS2}} forms a [[composite material|composite]] with improved strength as well as reduced friction. Polymers that may be filled with {{chem2|MoS2}} include [[nylon]] ([[trade name]] [[Nylatron]]), [[Teflon]] and [[Vespel]]. Self-lubricating composite coatings for high-temperature applications consist of molybdenum disulfide and [[titanium nitride]], using [[chemical vapor deposition]].

Examples of applications of {{chem2|MoS2}}-based lubricants include [[two-stroke engine]]s (such as motorcycle engines), bicycle [[coaster brakes]], automotive [[Constant-velocity joint|CV]] and [[universal joint]]s, ski waxes<ref>{{cite web| access-date = 2011-01-06| url = http://www.swixsport.com/dav/8dde5f4784.pdf| title = On dry lubricants in ski waxes| publisher = Swix Sport AX| url-status = dead| archive-url = https://web.archive.org/web/20110716174041/http://www.swixsport.com/dav/8dde5f4784.pdf| archive-date = 2011-07-16}}</ref> and [[bullet]]s.<ref>{{cite web| access-date = 2009-06-06| url = http://www.norma.cc/en/Ammunition-Academy/Barrel-wear/| title = Barrels retain accuracy longer with Diamond Line| publisher=Norma}}</ref>

Other layered inorganic materials that exhibit lubricating properties (collectively known as [[solid lubricant]]s (or dry lubricants)) includes graphite, which requires volatile additives and hexagonal [[boron nitride]].<ref>{{cite book|title=Ullmann's Encyclopedia of Industrial Chemistry|last=Bartels|first=Thorsten|publisher=Wiley VCH|year=2002|location=Weinheim|chapter=Lubricants and Lubrication|doi=10.1002/14356007.a15_423|display-authors=etal|isbn=978-3527306732}}</ref>

=== Catalysis ===
[[File:Molybdenum disulfide - 17.jpg|thumb|[[Fingerprint]] revealed by molybdenum disulfide]]
{{chem2|MoS2}} is employed as a [[catalyst|cocatalyst]] for desulfurization in [[petrochemistry]], for example, [[hydrodesulfurization]]. The effectiveness of the {{chem2|MoS2}} catalysts is enhanced by [[Doping (semiconductor)|doping]] with small amounts of [[cobalt]] or [[nickel]]. The intimate mixture of these sulfides is [[catalyst support|supported]] on [[alumina]]. Such catalysts are generated in situ by treating molybdate/cobalt or nickel-impregnated alumina with {{chem|H|2|S}} or an equivalent reagent. Catalysis does not occur at the regular sheet-like regions of the crystallites, but instead at the edge of these planes.<ref>{{cite book| last1= Topsøe| first1= H.| last2= Clausen| first2= B. S.| last3= Massoth| first3= F. E. | title =Hydrotreating Catalysis, Science and Technology| publisher = Springer-Verlag| location= Berlin| year = 1996}}</ref>

{{chem2|MoS2}} finds use as a [[hydrogenation]] catalyst for [[organic synthesis]].<ref name=Shigeo>{{cite book|last1=Nishimura|first1=Shigeo|title=Handbook of Heterogeneous Catalytic Hydrogenation for Organic Synthesis|date=2001|publisher=Wiley-Interscience| location= New York| isbn= 9780471396987|pages=43–44 & 240–241|edition=1st|url={{google books |plainurl=y |id=RjZRAAAAMAAJ|page=43}}}}</ref> As it is derived from a common [[transition metal]], rather than a [[group 10]] metal, {{chem2|MoS2}} is chosen when price or resistance to sulfur [[Catalyst poisoning|poisoning]] are of primary concern. {{chem2|MoS2}} is effective for the hydrogenation of [[nitro compounds]] to [[amines]] and can be used to produce [[Secondary (chemistry)|secondary]] amines via [[reductive amination]].<ref>{{cite journal|last1=Dovell|first1=Frederick S.| last2= Greenfield| first2= Harold| title=Base-Metal Sulfides as Reductive Alkylation Catalysts|journal=The Journal of Organic Chemistry|date=1964|volume=29|issue=5|pages=1265–1267|doi=10.1021/jo01028a511}}</ref> The catalyst can also effect [[hydrogenolysis]] of [[organosulfur compounds]], [[aldehyde]]s, [[ketone]]s, [[phenols]] and [[carboxylic acids]] to their respective [[alkane]]s.<ref name=Shigeo /> However, it suffers from low activity, often requiring hydrogen [[pressure]]s above 96 MPa and temperatures above 185&nbsp;°C.

== Research ==
{{chem2|MoS2}} plays an important role in [[condensed matter physics]] research.<ref name="Wood-2022">{{Cite web |last=Wood |first=Charlie |date=2022-08-16 |title=Physics Duo Finds Magic in Two Dimensions |url=https://www.quantamagazine.org/physics-duo-finds-magic-in-two-dimensions-20220816/ |access-date=2022-08-19 |website=Quanta Magazine |language=en}}</ref>

===Hydrogen evolution===
{{chem2|MoS2}} and related molybdenum sulfides are efficient catalysts for [[hydrogen evolution reaction|hydrogen evolution]], including the [[electrolysis of water]];<ref name="KibsgaardJaramillo2014">{{cite journal| last1= Kibsgaard| first1= Jakob| last2=Jaramillo|first2=Thomas F.|last3=Besenbacher|first3=Flemming|title=Building an appropriate active-site motif into a hydrogen-evolution catalyst with thiomolybdate [Mo<sub>3</sub>S<sub>13</sub>]<sup>2−</sup> clusters|journal=Nature Chemistry| volume= 6| issue= 3| year= 2014| pages= 248–253|doi=10.1038/nchem.1853|pmid=24557141|bibcode=2014NatCh...6..248K| url= https://zenodo.org/record/889641}}</ref><ref>{{cite journal| first1=A. B. | last1= Laursen| first2= S. | last2= Kegnaes| first3=S. | last3= Dahl | first4= I. | last4= Chorkendorff| title= Molybdenum Sulfides – Efficient and Viable Materials for Electro- and Photoelectrocatalytic Hydrogen Evolution| journal=Energy Environ. Sci.| year= 2012| volume= 5| issue= 2| pages= 5577–91| doi=10.1039/c2ee02618j}}</ref> thus, are possibly useful to produce hydrogen for use in [[fuel cell]]s.<ref name="Sandia12517">{{cite web|title=Superior hydrogen catalyst just grows that way|url=https://share-ng.sandia.gov/news/resources/news_releases/superior-catalyst/#.Wia84bbMw5s|website=share-ng.sandia.gov|publisher=Sandia Labs|access-date=December 5, 2017|format=news release|quote=a spray-printing process that uses molybdenum disulfide to create a “flowering” hydrogen catalyst far cheaper than platinum and reasonably close in efficiency.}}</ref>

=== Oxygen reduction and evolution ===
{{chem2|MoS2}}@Fe-''N''-C core/shell<ref>{{Cite journal |last1=Yan |first1=Yan |last2=Liang |first2=Shuang |last3=Wang |first3=Xiang |last4=Zhang |first4=Mingyue |last5=Hao |first5=Shu-Meng |last6=Cui |first6=Xun |last7=Li |first7=Zhiwei |last8=Lin |first8=Zhiqun |date=2021-10-05 |title=Robust wrinkled MoS 2 /N-C bifunctional electrocatalysts interfaced with single Fe atoms for wearable zinc-air batteries |journal=Proceedings of the National Academy of Sciences |language=en |volume=118 |issue=40 |pages=e2110036118 |doi=10.1073/pnas.2110036118 |issn=0027-8424 |pmc=8501804 |pmid=34588309|bibcode=2021PNAS..11810036Y |doi-access=free}}</ref> nanosphere with atomic Fe-doped surface and interface ({{chem2|MoS2}}/Fe-''N''-C) can be used as a used an electrocatalyst for oxygen reduction and evolution reactions (ORR and OER) bifunctionally because of reduced energy barrier due to Fe-N<sub>4</sub> dopants and unique nature of {{chem2|MoS2}}/Fe-''N''-C interface.

===Microelectronics===
As in [[graphene]], the layered structures of {{chem2|MoS2}} and other [[transition metal]] [[dichalcogenide]]s exhibit electronic and optical properties<ref name="nano">{{Cite journal | last1 = Wang | first1 = Q. H. | last2 = Kalantar-Zadeh | first2 = K. | last3 = Kis | first3 = A. | last4 = Coleman | first4 = J. N. | last5 = Strano | first5 = M. S. | title = Electronics and optoelectronics of two-dimensional transition metal dichalcogenides | doi = 10.1038/nnano.2012.193 | journal = Nature Nanotechnology | volume = 7 | issue = 11 | pages = 699–712 | year = 2012 | pmid = 23132225| bibcode = 2012NatNa...7..699W | s2cid = 6261931 | url = http://infoscience.epfl.ch/record/182177}}</ref> that can differ from those in bulk.<ref name=promising>{{cite journal| first1=R. |last1=Ganatra |first2= Q. |last2= Zhang| title= Few-Layer MoS<sub>2</sub>: A Promising Layered Semiconductor| journal= ACS Nano| year= 2014| volume= 8|issue=5 | pages= 4074–99| doi=10.1021/nn405938z|pmid=24660756}}</ref> Bulk {{chem2|MoS2}} has an indirect band gap of 1.2 eV,<ref>{{cite journal|doi=10.1038/ncomms4087|pmid=24435154|title=Electronic transport and device prospects of monolayer molybdenum disulphide grown by chemical vapour deposition|journal=Nature Communications|volume=5|pages=3087|year=2014|last1=Zhu|first1=Wenjuan|last2=Low|first2=Tony|last3=Lee|first3=Yi-Hsien|last4=Wang|first4=Han|last5=Farmer|first5=Damon B.|last6=Kong|first6=Jing|last7=Xia|first7=Fengnian|last8=Avouris|first8=Phaedon|bibcode=2014NatCo...5.3087Z|arxiv=1401.4951|s2cid=6075401}}</ref><ref>{{cite journal|doi=10.1038/ncomms7293|pmid=25695374|pmc=4346634|title=Exploring atomic defects in molybdenum disulphide monolayers|journal=Nature Communications|volume=6|pages=6293|year=2015|last1=Hong|first1=Jinhua|last2=Hu|first2=Zhixin|last3=Probert|first3=Matt|last4=Li|first4=Kun|last5=Lv|first5=Danhui|last6=Yang|first6=Xinan|last7=Gu|first7=Lin|last8=Mao|first8=Nannan|last9=Feng|first9=Qingliang|last10=Xie|first10=Liming|last11=Zhang|first11=Jin|last12=Wu|first12=Dianzhong|last13=Zhang|first13=Zhiyong|last14=Jin|first14=Chuanhong|last15=Ji|first15=Wei|last16=Zhang|first16=Xixiang|last17=Yuan|first17=Jun|last18=Zhang|first18=Ze|bibcode=2015NatCo...6.6293H}}</ref> while [[Transition metal dichalcogenide monolayers|{{chem2|MoS2}} monolayers]] have a direct 1.8 eV [[band gap|electronic bandgap]],<ref name= Splendiani>{{cite journal|last1=Splendiani| first1=A.| last2= Sun| first2= L.| last3= Zhang| first3=Y.| last4= Li| first4= T.| last5= Kim| first5= J.|last6=Chim|first6=J.|last7=F.|year=2010|title=Emerging Photoluminescence in Monolayer MoS<sub>2</sub>|journal=Nano Letters|volume=10|issue=4|pages=1271–1275| doi=10.1021/nl903868w| pmid=20229981|bibcode=2010NanoL..10.1271S|last8=Wang|first8=Feng}}</ref> supporting switchable transistors<ref name="Radisavljevic" /> and [[photodetectors]].<ref>{{cite journal | last1 = Lopez-Sanchez | first1 = O. | last2 = Lembke | first2 = D. | last3 = Kayci | first3 = M. | last4 = Radenovic | first4 = A. | last5 = Kis | first5 = A. | year = 2013 | title = Ultrasensitive photodetectors based on monolayer MoS<sub>2</sub> | journal = Nature Nanotechnology | volume = 8 | issue = 7| pages = 497–501 | doi = 10.1038/nnano.2013.100 | pmid = 23748194 | bibcode = 2013NatNa...8..497L | s2cid = 5435971 | url = http://infoscience.epfl.ch/record/183895}}</ref><ref name=promising /><ref>{{cite journal| first1=C. N. R. |last1= Rao| first2= H. S. S. |last2=Ramakrishna Matte |first3=U. |last3=Maitra| title= Graphene Analogues of Inorganic Layered Materials| journal= Angew. Chem.| edition= International| year= 2013| volume= 52|issue= 50| pages= 13162–85|doi=10.1002/anie.201301548|pmid= 24127325}}</ref>

{{chem2|MoS2}} nanoflakes can be used for solution-processed fabrication of layered [[Memristor|memristive]] and memcapacitive devices through engineering a {{chem2|MoO_{''x''}|}}/{{chem2|MoS2}} heterostructure sandwiched between silver electrodes.<ref name="flexible_memristor">{{Cite journal | doi = 10.1038/nmat4135| pmid = 25384168| title = Layered memristive and memcapacitive switches for printable electronics| journal = Nature Materials| volume = 14| issue = 2| pages = 199–204| year = 2014| last1 = Bessonov | first1 = A. A. | last2 = Kirikova | first2 = M. N. | last3 = Petukhov | first3 = D. I. | last4 = Allen | first4 = M. | last5 = Ryhänen | first5 = T. | last6 = Bailey | first6 = M. J. A. | bibcode = 2015NatMa..14..199B}}</ref> {{chem2|MoS2}}-based [[memristor]]s are mechanically flexible, optically transparent and can be produced at low cost.

The sensitivity of a graphene [[field-effect transistor]] (FET) [[Bio-FET|biosensor]] is fundamentally restricted by the zero band gap of graphene, which results in increased leakage and reduced sensitivity. In digital electronics, transistors control current flow throughout an integrated circuit and allow for amplification and switching. In biosensing, the physical gate is removed and the binding between embedded receptor molecules and the charged target biomolecules to which they are exposed modulates the current.<ref name=rad1409>{{cite news |title=Ultrasensitive biosensor from molybdenite semiconductor outshines graphene |date= 4 September 2014 |url=http://www.rdmag.com/news/2014/09/ultrasensitive-biosensor-molybdenite-semiconductor-outshines-graphene?et_cid=4135513&et_rid=677699018&location=top |work=R&D Magazine}}</ref>

{{chem2|MoS2}} has been investigated as a component of flexible circuits.<ref name=UT>{{Cite journal|title = Two-dimensional flexible nanoelectronics|journal = Nature Communications|date = 2014-12-17|pages = 5678|volume = 5|doi = 10.1038/ncomms6678|first1 = Deji|last1 = Akinwande|first2 = Nicholas|last2 = Petrone|first3 = James|last3 = Hone|pmid=25517105|bibcode = 2014NatCo...5.5678A|doi-access = free}}</ref><ref name="Chang-2015">{{Cite journal|title = Large-Area Monolayer MoS<sub>2</sub> for Flexible Low-Power RF Nanoelectronics in the GHz Regime|journal = Advanced Materials|date = 2015-12-01|pages = 1818–1823|doi = 10.1002/adma.201504309|pmid = 26707841|first1 = Hsiao-Yu|last1 = Chang|first2 = Maruthi Nagavalli|last2 = Yogeesh|first3 = Rudresh|last3 = Ghosh|first4 = Amritesh|last4 = Rai|first5 = Atresh|last5 = Sanne|first6 = Shixuan|last6 = Yang|first7 = Nanshu|last7 = Lu|first8 = Sanjay Kumar|last8 = Banerjee|first9 = Deji|last9 = Akinwande|volume=28|issue = 9| s2cid=205264837|doi-access = free}}</ref>

In 2017, a 115-transistor, 1-bit [[microprocessor]] implementation was fabricated using two-dimensional {{chem2|MoS2}}.<ref>{{Cite journal|last1=Wachter|first1=Stefan|last2=Polyushkin|first2=Dmitry K.|last3=Bethge|first3=Ole|last4=Mueller|first4=Thomas|date=2017-04-11|title=A microprocessor based on a two-dimensional semiconductor|journal=Nature Communications|language=en|volume=8|pages=14948|doi=10.1038/ncomms14948|pmid=28398336|pmc=5394242|issn=2041-1723|bibcode=2017NatCo...814948W|arxiv=1612.00965}}</ref>

{{chem2|MoS2}} has been used to create 2D 2-terminal [[memristor]]s and 3-terminal [[memtransistor]]s.<ref>{{Cite news|url=https://www.nextbigfuture.com/2018/02/memtransistors-advance-neuromorphic-computing.html|title=Memtransistors advance neuromorphic computing {{!}} NextBigFuture.com|date=2018-02-24|work=NextBigFuture.com|access-date=2018-02-27|language=en-US}}</ref>

=== Valleytronics ===
Due to the lack of spatial inversion symmetry, odd-layer MoS2 is a promising material for [[valleytronics]] because both the CBM and VBM have two energy-degenerate valleys at the corners of the first Brillouin zone, providing an exciting opportunity to store the information of 0s and 1s at different discrete values of the crystal momentum. The [[Berry curvature]] is even under spatial inversion (P) and odd under time reversal (T), the valley Hall effect cannot survive when both P and T symmetries are present. To excite valley Hall effect in specific valleys, circularly polarized lights were used for breaking the T symmetry in atomically thin transition-metal dichalcogenides.<ref>{{Cite journal |last1=Mak |first1=Kin Fai |last2=He |first2=Keliang |last3=Shan |first3=Jie |last4=Heinz |first4=Tony F. |title=Control of valley polarization in monolayer MoS2 by optical helicity |url=https://www.nature.com/articles/nnano.2012.96 |journal=Nature Nanotechnology |year=2012 |language=en |volume=7 |issue=8 |pages=494–498 |doi=10.1038/nnano.2012.96|pmid=22706698 |arxiv=1205.1822 |bibcode=2012NatNa...7..494M |s2cid=23248686}}</ref> In monolayer {{chem2|MoS2}}, the T and mirror symmetries lock the spin and valley indices of the sub-bands split by the spin-orbit couplings, both of which are flipped under T; the spin conservation suppresses the inter-valley scattering. Therefore, monolayer MoS2 have been deemed an ideal platform for realizing intrinsic valley Hall effect without extrinsic symmetry breaking.<ref>{{Cite journal |last1=Wu |first1=Zefei |last2=Zhou |first2=Benjamin T. |last3=Cai |first3=Xiangbin |last4=Cheung |first4=Patrick |last5=Liu |first5=Gui-Bin |last6=Huang |first6=Meizhen |last7=Lin |first7=Jiangxiazi |last8=Han |first8=Tianyi |last9=An |first9=Liheng |last10=Wang |first10=Yuanwei |last11=Xu |first11=Shuigang |last12=Long |first12=Gen |last13=Cheng |first13=Chun |last14=Law |first14=Kam Tuen |last15=Zhang |first15=Fan |date=2019-02-05 |title=Intrinsic valley Hall transport in atomically thin MoS2 |journal=Nature Communications |volume=10 |issue=1 |pages=611 |doi=10.1038/s41467-019-08629-9|pmid=30723283 |pmc=6363770 |arxiv=1805.06686 |bibcode=2019NatCo..10..611W}}</ref>

=== Photonics and photovoltaics ===
{{chem2|MoS2}} also possesses mechanical strength, electrical conductivity, and can emit light, opening possible applications such as photodetectors.<ref>{{Cite web|url = http://www.gizmag.com/molybdenum-di-sulphide-metal-graphene/33980|title = Metal-based graphene alternative "shines" with promise|date = September 25, 2014|access-date = September 30, 2014|publisher = Gizmag|last = Coxworth|first = Ben}}</ref> {{chem2|MoS2}} has been investigated as a component of photoelectrochemical (e.g. for photocatalytic hydrogen production) applications and for microelectronics applications.<ref name="Radisavljevic">{{cite journal|last1=Radisavljevic|first1=B.|last2=Radenovic|first2=A.|last3=Brivio|first3=J.|last4=Giacometti|first4=V.|last5=Kis|first5=A.|year=2011| title=Single-layer MoS<sub>2</sub> transistors| journal=Nature Nanotechnology| volume=6| issue=3| pages=147–150|doi=10.1038/nnano.2010.279| pmid=21278752|bibcode=2011NatNa...6..147R|url=http://infoscience.epfl.ch/record/164049}}</ref>

===Superconductivity of monolayers===
Under an electric field {{chem2|MoS2}} monolayers have been found to superconduct at temperatures below 9.4 K.<ref name=APL2012>{{Cite journal|url=https://aip.scitation.org/doi/abs/10.1063/1.4740268|title=Electric-field-induced superconductivity at 9.4 K in a layered transition metal disulphide MoS2|first1=Kouji|last1=Taniguchi|first2=Akiyo|last2=Matsumoto|first3=Hidekazu|last3=Shimotani|first4=Hidenori|last4=Takagi|date=July 23, 2012|journal=Applied Physics Letters|volume=101|issue=4|pages=042603|via=aip.scitation.org (Atypon)|doi=10.1063/1.4740268|bibcode=2012ApPhL.101d2603T}}</ref>

== See also ==
* [[Molybdenum diselenide]]

== References ==
{{reflist|30em}}

== External links ==
* {{Cite web |last=Wood |first=Charlie |date=2022-08-16 |title=Physics Duo Finds Magic in Two Dimensions |url=https://www.quantamagazine.org/physics-duo-finds-magic-in-two-dimensions-20220816/ |access-date=2022-08-19 |website=Quanta Magazine |language=en}}
{{Commons category|Molybdenum disulfide}}
{{Molybdenum compounds}}
{{sulfides}}

[[Category:Molybdenum(IV) compounds]]
[[Category:Disulfides]]
[[Category:Non-petroleum based lubricants]]
[[Category:Dry lubricants]]
[[Category:Semiconductor materials]]
[[Category:Transition metal dichalcogenides]]
[[Category:Hydrogenation catalysts]]
[[Category:Monolayers]]

Latest revision as of 04:39, 7 January 2025

Molybdenum disulfide
Molybdenum disulfide
Names
IUPAC name
Molybdenum disulfide
Other names
Molybdenum(IV) sulfide
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.013.877 Edit this at Wikidata
RTECS number
  • QA4697000
UNII
  • InChI=1S/Mo.2S checkY
    Key: CWQXQMHSOZUFJS-UHFFFAOYSA-N checkY
  • InChI=1/Mo.2S/rMoS2/c2-1-3
    Key: CWQXQMHSOZUFJS-FRBXWHJUAU
  • S=[Mo]=S
Properties
MoS2
Molar mass 160.07 g·mol−1
Appearance black/lead-gray solid
Density 5.06 g/cm3[1]
Melting point 2,375 °C (4,307 °F; 2,648 K)[4]
insoluble[1]
Solubility decomposed by aqua regia, hot sulfuric acid, nitric acid
insoluble in dilute acids
Band gap 1.23 eV (indirect, 3R or 2H bulk)[2]
~1.8 eV (direct, monolayer)[3]
Structure
hP6, P6
3/mmc, No. 194 (2H)

hR9, R3m, No 160 (3R)[5]

a = 0.3161 nm (2H), 0.3163 nm (3R), c = 1.2295 nm (2H), 1.837 (3R)
Trigonal prismatic (MoIV)
Pyramidal (S2−)
Thermochemistry
62.63 J/(mol·K)
−235.10 kJ/mol
−225.89 kJ/mol
Hazards
Safety data sheet (SDS) External MSDS
Related compounds
Other anions
 Molybdenum(IV) oxide
Molybdenum diselenide
Molybdenum ditelluride
Other cations
 Tungsten disulfide
Related lubricants
 Graphite
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)
"Molybdenum sulfide" redirects here. Not to be confused with Molybdenum trisulfide.

Molybdenum disulfide (or moly) is an inorganic compound composed of molybdenum and sulfur. Its chemical formula is MoS2.

The compound is classified as a transition metal dichalcogenide. It is a silvery black solid that occurs as the mineral molybdenite, the principal ore for molybdenum.[6] MoS2 is relatively unreactive. It is unaffected by dilute acids and oxygen. In appearance and feel, molybdenum disulfide is similar to graphite. It is widely used as a dry lubricant because of its low friction and robustness. Bulk MoS2 is a diamagnetic, indirect bandgap semiconductor similar to silicon, with a bandgap of 1.23 eV.[2]

Production

[edit]
Molybdenite

MoS2 is naturally found as either molybdenite, a crystalline mineral, or jordisite, a rare low temperature form of molybdenite.[7] Molybdenite ore is processed by flotation to give relatively pure MoS2. The main contaminant is carbon. MoS2 also arises by thermal treatment of virtually all molybdenum compounds with hydrogen sulfide or elemental sulfur and can be produced by metathesis reactions from molybdenum pentachloride.[8]

Structure and physical properties

[edit]
Electron microscopy of antisites (a, Mo substitutes for S) and vacancies (b, missing S atoms) in a monolayer of molybdenum disulfide. Scale bar: 1 nm.[9]

Crystalline phases

[edit]

All forms of MoS2 have a layered structure, in which a plane of molybdenum atoms is sandwiched by planes of sulfide ions. These three strata form a monolayer of MoS2. Bulk MoS2 consists of stacked monolayers, which are held together by weak van der Waals interactions.

Crystalline MoS2 exists in one of two phases, 2H-MoS2 and 3R-MoS2, where the "H" and the "R" indicate hexagonal and rhombohedral symmetry, respectively. In both of these structures, each molybdenum atom exists at the center of a trigonal prismatic coordination sphere and is covalently bonded to six sulfide ions. Each sulfur atom has pyramidal coordination and is bonded to three molybdenum atoms. Both the 2H- and 3R-phases are semiconducting.[10]

A third, metastable crystalline phase known as 1T-MoS2 was discovered by intercalating 2H-MoS2 with alkali metals.[11] This phase has trigonal symmetry and is metallic. The 1T-phase can be stabilized through doping with electron donors such as rhenium,[12] or converted back to the 2H-phase by microwave radiation.[13] The 2H/1T-phase transition can be controlled via the incorporation of sulfur (S) vacancies.[14]

Allotropes

[edit]

Nanotube-like and buckyball-like molecules composed of MoS2 are known.[15]

Exfoliated MoS2 flakes

[edit]

While bulk MoS2 in the 2H-phase is known to be an indirect-band gap semiconductor, monolayer MoS2 has a direct band gap. The layer-dependent optoelectronic properties of MoS2 have promoted much research in 2-dimensional MoS2-based devices. 2D MoS2 can be produced by exfoliating bulk crystals to produce single-layer to few-layer flakes either through a dry, micromechanical process or through solution processing.

Micromechanical exfoliation, also pragmatically called "Scotch-tape exfoliation", involves using an adhesive material to repeatedly peel apart a layered crystal by overcoming the van der Waals forces. The crystal flakes can then be transferred from the adhesive film to a substrate. This facile method was first used by Konstantin Novoselov and Andre Geim to obtain graphene from graphite crystals. However, it can not be employed for a uniform 1-D layers because of weaker adhesion of MoS2 to the substrate (either silicon, glass or quartz); the aforementioned scheme is good for graphene only.[16] While Scotch tape is generally used as the adhesive tape, PDMS stamps can also satisfactorily cleave MoS2 if it is important to avoid contaminating the flakes with residual adhesive.[17]

Liquid-phase exfoliation can also be used to produce monolayer to multi-layer MoS2 in solution. A few methods include lithium intercalation[18] to delaminate the layers and sonication in a high-surface tension solvent.[19][20]

Mechanical properties

[edit]

MoS2 excels as a lubricating material (see below) due to its layered structure and low coefficient of friction. Interlayer sliding dissipates energy when a shear stress is applied to the material. Extensive work has been performed to characterize the coefficient of friction and shear strength of MoS2 in various atmospheres.[21] The shear strength of MoS2 increases as the coefficient of friction increases. This property is called superlubricity. At ambient conditions, the coefficient of friction for MoS2 was determined to be 0.150, with a corresponding estimated shear strength of 56.0 MPa.[21] Direct methods of measuring the shear strength indicate that the value is closer to 25.3 MPa.[22]

The wear resistance of MoS2 in lubricating applications can be increased by doping MoS2 with Cr. Microindentation experiments on nanopillars of Cr-doped MoS2 found that the yield strength increased from an average of 821 MPa for pure MoS2 (at 0% Cr) to 1017 MPa at 50% Cr.[23] The increase in yield strength is accompanied by a change in the failure mode of the material. While the pure MoS2 nanopillar fails through a plastic bending mechanism, brittle fracture modes become apparent as the material is loaded with increasing amounts of dopant.[23]

The widely used method of micromechanical exfoliation has been carefully studied in MoS2 to understand the mechanism of delamination in few-layer to multi-layer flakes. The exact mechanism of cleavage was found to be layer dependent. Flakes thinner than 5 layers undergo homogenous bending and rippling, while flakes around 10 layers thick delaminated through interlayer sliding. Flakes with more than 20 layers exhibited a kinking mechanism during micromechanical cleavage. The cleavage of these flakes was also determined to be reversible due to the nature of van der Waals bonding.[24]

In recent years, MoS2 has been utilized in flexible electronic applications, promoting more investigation into the elastic properties of this material. Nanoscopic bending tests using AFM cantilever tips were performed on micromechanically exfoliated MoS2 flakes that were deposited on a holey substrate.[17][25] The yield strength of monolayer flakes was 270 GPa,[25] while the thicker flakes were also stiffer, with a yield strength of 330 GPa.[17] Molecular dynamic simulations found the in-plane yield strength of MoS2 to be 229 GPa, which matches the experimental results within error.[26]

Bertolazzi and coworkers also characterized the failure modes of the suspended monolayer flakes. The strain at failure ranges from 6 to 11%. The average yield strength of monolayer MoS2 is 23 GPa, which is close to the theoretical fracture strength for defect-free MoS2.[25]

The band structure of MoS2 is sensitive to strain.[27][28][29]

Chemical reactions

[edit]

Molybdenum disulfide is stable in air and attacked only by aggressive reagents. It reacts with oxygen upon heating forming molybdenum trioxide:

2 MoS2 + 7 O2 → 2 MoO3 + 4 SO2

Chlorine attacks molybdenum disulfide at elevated temperatures to form molybdenum pentachloride:

2 MoS2 + 7 Cl2 → 2 MoCl5 + 2 S2Cl2

Intercalation reactions

[edit]

Molybdenum disulfide is a host for formation of intercalation compounds. This behavior is relevant to its use as a cathode material in batteries.[30][31] One example is a lithiated material, LixMoS2.[32] With butyl lithium, the product is LiMoS2.[6]

Applications

[edit]

Lubricant

[edit]
A tube of commercial graphite powder lubricant with molybdenum disulfide additive (called "molybdenum")[33]

Due to weak van der Waals interactions between the sheets of sulfide atoms, MoS2 has a low coefficient of friction. MoS2 in particle sizes in the range of 1–100 μm is a common dry lubricant.[34] Few alternatives exist that confer high lubricity and stability at up to 350 °C in oxidizing environments. Sliding friction tests of MoS2 using a pin on disc tester at low loads (0.1–2 N) give friction coefficient values of <0.1.[35][36]

MoS2 is often a component of blends and composites that require low friction. For example, it is added to graphite to improve sticking.[33] A variety of oils and greases are used, because they retain their lubricity even in cases of almost complete oil loss, thus finding a use in critical applications such as aircraft engines. When added to plastics, MoS2 forms a composite with improved strength as well as reduced friction. Polymers that may be filled with MoS2 include nylon (trade name Nylatron), Teflon and Vespel. Self-lubricating composite coatings for high-temperature applications consist of molybdenum disulfide and titanium nitride, using chemical vapor deposition.

Examples of applications of MoS2-based lubricants include two-stroke engines (such as motorcycle engines), bicycle coaster brakes, automotive CV and universal joints, ski waxes[37] and bullets.[38]

Other layered inorganic materials that exhibit lubricating properties (collectively known as solid lubricants (or dry lubricants)) includes graphite, which requires volatile additives and hexagonal boron nitride.[39]

Catalysis

[edit]
Fingerprint revealed by molybdenum disulfide

MoS2 is employed as a cocatalyst for desulfurization in petrochemistry, for example, hydrodesulfurization. The effectiveness of the MoS2 catalysts is enhanced by doping with small amounts of cobalt or nickel. The intimate mixture of these sulfides is supported on alumina. Such catalysts are generated in situ by treating molybdate/cobalt or nickel-impregnated alumina with H
2S or an equivalent reagent. Catalysis does not occur at the regular sheet-like regions of the crystallites, but instead at the edge of these planes.[40]

MoS2 finds use as a hydrogenation catalyst for organic synthesis.[41] As it is derived from a common transition metal, rather than a group 10 metal, MoS2 is chosen when price or resistance to sulfur poisoning are of primary concern. MoS2 is effective for the hydrogenation of nitro compounds to amines and can be used to produce secondary amines via reductive amination.[42] The catalyst can also effect hydrogenolysis of organosulfur compounds, aldehydes, ketones, phenols and carboxylic acids to their respective alkanes.[41] However, it suffers from low activity, often requiring hydrogen pressures above 96 MPa and temperatures above 185 °C.

Research

[edit]

MoS2 plays an important role in condensed matter physics research.[43]

Hydrogen evolution

[edit]

MoS2 and related molybdenum sulfides are efficient catalysts for hydrogen evolution, including the electrolysis of water;[44][45] thus, are possibly useful to produce hydrogen for use in fuel cells.[46]

Oxygen reduction and evolution

[edit]

MoS2@Fe-N-C core/shell[47] nanosphere with atomic Fe-doped surface and interface (MoS2/Fe-N-C) can be used as a used an electrocatalyst for oxygen reduction and evolution reactions (ORR and OER) bifunctionally because of reduced energy barrier due to Fe-N4 dopants and unique nature of MoS2/Fe-N-C interface.

Microelectronics

[edit]

As in graphene, the layered structures of MoS2 and other transition metal dichalcogenides exhibit electronic and optical properties[48] that can differ from those in bulk.[49] Bulk MoS2 has an indirect band gap of 1.2 eV,[50][51] while MoS2 monolayers have a direct 1.8 eV electronic bandgap,[52] supporting switchable transistors[53] and photodetectors.[54][49][55]

MoS2 nanoflakes can be used for solution-processed fabrication of layered memristive and memcapacitive devices through engineering a MoOx/MoS2 heterostructure sandwiched between silver electrodes.[56] MoS2-based memristors are mechanically flexible, optically transparent and can be produced at low cost.

The sensitivity of a graphene field-effect transistor (FET) biosensor is fundamentally restricted by the zero band gap of graphene, which results in increased leakage and reduced sensitivity. In digital electronics, transistors control current flow throughout an integrated circuit and allow for amplification and switching. In biosensing, the physical gate is removed and the binding between embedded receptor molecules and the charged target biomolecules to which they are exposed modulates the current.[57]

MoS2 has been investigated as a component of flexible circuits.[58][59]

In 2017, a 115-transistor, 1-bit microprocessor implementation was fabricated using two-dimensional MoS2.[60]

MoS2 has been used to create 2D 2-terminal memristors and 3-terminal memtransistors.[61]

Valleytronics

[edit]

Due to the lack of spatial inversion symmetry, odd-layer MoS2 is a promising material for valleytronics because both the CBM and VBM have two energy-degenerate valleys at the corners of the first Brillouin zone, providing an exciting opportunity to store the information of 0s and 1s at different discrete values of the crystal momentum. The Berry curvature is even under spatial inversion (P) and odd under time reversal (T), the valley Hall effect cannot survive when both P and T symmetries are present. To excite valley Hall effect in specific valleys, circularly polarized lights were used for breaking the T symmetry in atomically thin transition-metal dichalcogenides.[62] In monolayer MoS2, the T and mirror symmetries lock the spin and valley indices of the sub-bands split by the spin-orbit couplings, both of which are flipped under T; the spin conservation suppresses the inter-valley scattering. Therefore, monolayer MoS2 have been deemed an ideal platform for realizing intrinsic valley Hall effect without extrinsic symmetry breaking.[63]

Photonics and photovoltaics

[edit]

MoS2 also possesses mechanical strength, electrical conductivity, and can emit light, opening possible applications such as photodetectors.[64] MoS2 has been investigated as a component of photoelectrochemical (e.g. for photocatalytic hydrogen production) applications and for microelectronics applications.[53]

Superconductivity of monolayers

[edit]

Under an electric field MoS2 monolayers have been found to superconduct at temperatures below 9.4 K.[65]

See also

[edit]

References

[edit]
  1. ^ a b Haynes, William M., ed. (2011). CRC Handbook of Chemistry and Physics (92nd ed.). Boca Raton, Florida: CRC Press. p. 4.76. ISBN 1-4398-5511-0.
  2. ^ a b Kobayashi, K.; Yamauchi, J. (1995). "Electronic structure and scanning-tunneling-microscopy image of molybdenum dichalcogenide surfaces". Physical Review B. 51 (23): 17085–17095. Bibcode:1995PhRvB..5117085K. doi:10.1103/PhysRevB.51.17085. PMID 9978722.
  3. ^ Yun, Won Seok; Han, S. W.; Hong, Soon Cheol; Kim, In Gee; Lee, J. D. (2012). "Thickness and strain effects on electronic structures of transition metal dichalcogenides: 2H-MX2 semiconductors (M = Mo, W; X = S, Se, Te)". Physical Review B. 85 (3): 033305. Bibcode:2012PhRvB..85c3305Y. doi:10.1103/PhysRevB.85.033305.
  4. ^ "Molybdenum Disulfide". PubChem. Retrieved August 31, 2018.
  5. ^ Schönfeld, B.; Huang, J. J.; Moss, S. C. (1983). "Anisotropic mean-square displacements (MSD) in single-crystals of 2H- and 3R-MoS2". Acta Crystallographica Section B. 39 (4): 404–407. Bibcode:1983AcCrB..39..404S. doi:10.1107/S0108768183002645.
  6. ^ a b Sebenik, Roger F. et al. (2005) "Molybdenum and Molybdenum Compounds", Ullmann's Encyclopedia of Chemical Technology. Wiley-VCH, Weinheim. doi:10.1002/14356007.a16_655
  7. ^ "Jordisite". www.mindat.org.
  8. ^ Murphy, Donald W.; Interrante, Leonard V.; Kaner; Mansuktto (1995). "Metathetical Precursor Route to Molybdenum Disulfide". Inorganic Syntheses. Vol. 30. pp. 33–37. doi:10.1002/9780470132616.ch8. ISBN 9780470132616.
  9. ^ Hong, J.; Hu, Z.; Probert, M.; Li, K.; Lv, D.; Yang, X.; Gu, L.; Mao, N.; Feng, Q.; Xie, L.; Zhang, J.; Wu, D.; Zhang, Z.; Jin, C.; Ji, W.; Zhang, X.; Yuan, J.; Zhang, Z. (2015). "Exploring atomic defects in molybdenum disulphide monolayers". Nature Communications. 6: 6293. Bibcode:2015NatCo...6.6293H. doi:10.1038/ncomms7293. PMC 4346634. PMID 25695374.
  10. ^ Gmelin Handbook of Inorganic and Organometallic Chemistry - 8th edition (in German).
  11. ^ Wypych, Fernando; Schöllhorn, Robert (1992-01-01). "1T-MoS2, a new metallic modification of molybdenum disulfide". Journal of the Chemical Society, Chemical Communications (19): 1386–1388. doi:10.1039/C39920001386. ISSN 0022-4936.
  12. ^ Enyashin, Andrey N.; Yadgarov, Lena; Houben, Lothar; Popov, Igor; Weidenbach, Marc; Tenne, Reshef; Bar-Sadan, Maya; Seifert, Gotthard (2011-12-22). "New Route for Stabilization of 1T-WS2 and MoS2 Phases". The Journal of Physical Chemistry C. 115 (50): 24586–24591. arXiv:1110.3848. doi:10.1021/jp2076325. ISSN 1932-7447. S2CID 95117205.
  13. ^ Xu, Danyun; Zhu, Yuanzhi; Liu, Jiapeng; Li, Yang; Peng, Wenchao; Zhang, Guoliang; Zhang, Fengbao; Fan, Xiaobin (2016). "Microwave-assisted 1T to 2H phase reversion of MoS 2 in solution: a fast route to processable dispersions of 2H-MoS 2 nanosheets and nanocomposites". Nanotechnology. 27 (38): 385604. Bibcode:2016Nanot..27L5604X. doi:10.1088/0957-4484/27/38/385604. ISSN 0957-4484. PMID 27528593. S2CID 23849142.
  14. ^ Gan, Xiaorong; Lee, Lawrence Yoon Suk; Wong, Kwok-yin; Lo, Tsz Wing; Ho, Kwun Hei; Lei, Dang Yuan; Zhao, Huimin (2018-09-24). "2H/1T Phase Transition of Multilayer MoS 2 by Electrochemical Incorporation of S Vacancies". ACS Applied Energy Materials. 1 (9): 4754–4765. doi:10.1021/acsaem.8b00875. ISSN 2574-0962. S2CID 106014720.
  15. ^ Tenne, R.; Redlich, M. (2010). "Recent progress in the research of inorganic fullerene-like nanoparticles and inorganic nanotubes". Chemical Society Reviews. 39 (5): 1423–34. doi:10.1039/B901466G. PMID 20419198.
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