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MOLYBDENUM DISULFIDE (MoS2)

Molybdenum Disulfide (MoS2) is used dry lubricant and lubricant additive.
Molybdenum Disulfide (MoS2) is used hydrogenation catalyst.
Molybdenum Disulfide (MoS2) is one of the most widely used lubricants in space systems.

CAS Number: 1317-33-5
EC Number: 215-172-4
MDL number: MFCD00003470
Chemical formula: MoS2

SYNONYMS:
Molybdenum disulfide, Molybdenum(IV) sulfide, MOLYBDENUM DISULFIDE, Molybdenum(IV) sulfide, 1317-33-5, Molybdenite, Molybdenum disulphide, 1309-56-4,
Molybdenite (MoS2), Molybdenum sulfide (MoS2), bis(sulfanylidene)molybdenum, Pigment Black 34, ZC8B4P503V, MFCD00003470, Molysulfide, Molykote, Motimol,
Nichimoly C, Sumipowder PA, Molykote Z, Molyke R, T-Powder, Moly Powder B, Moly Powder C, Moly Powder PA, Moly Powder PS, Mopol M, Mopol S, Natural molybdenite, 56780-54-2, Molybdenum bisulfide, M 5 (lubricant), Liqui-Moly LM 2, Solvest 390A, DM 1 (sulfide), Liqui-Moly LM 11, MoS2, Molycolloid CF 626, LM 13 (lubricant), MD 40 (lubricant), Molykote Microsize Powder, Molybdenum ores, molybdenite, 863767-83-3, DAG-V 657, HSDB 1660, DAG 206, DAG 325, LM 13,
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Molybdenum Disulfide (MoS2) [molybdenum(IV) sulfide, MoS2] is an inorganic compound that exists in nature in the mineral molybdenite.
Molybdenum Disulfide (MoS2)'s crystals have a hexagonal layered structure (shown) that is similar to graphite.
In 1957, Ronald E. Bell and Robert E. Herfert at the now-defunct Climax Molybdenum Company of Michigan (Ann Arbor) prepared what was then a new rhombohedral crystalline form of Molybdenum Disulfide (MoS2).

Rhombohedral crystals were subsequently discovered in nature.
Like most mineral salts, Molybdenum Disulfide (MoS2) has a high melting point, but it begins to sublime at a relatively low 450 ºC.
This property is useful for purifying Molybdenum Disulfide (MoS2).

Because of its layered structure, hexagonal Molybdenum Disulfide (MoS2), like graphite, is an excellent “dry” lubricant.
Molybdenum Disulfide (MoS2) and its cousin tungsten disulfide can be used as surface coatings on machine parts (e.g., in the aerospace industry), in two-stroke engines (the type used for motorcycles), and in gun barrels (to reduce friction between the bullet and the barrel).

Unlike graphite, Molybdenum Disulfide (MoS2) does not depend on adsorbed water or other vapors for its lubricant properties.
Molybdenum Disulfide (MoS2) can be used at temperatures as high as 350 ºC in oxidizing environments and up to 1100 ºC in nonoxidizing environments.
Its stability makes Molybdenum Disulfide (MoS2) useful in high-temperature applications in which oils and greases are not practical.

In addition to its lubricating properties, Molybdenum Disulfide (MoS2) is a semiconductor.
Molybdenum Disulfide (MoS2) is also known that it and other semiconducting transition-metal chalcogenides become superconductors at their surfaces when doped with an electrostatic field.

The mechanism of superconductivity was uncertain until 2018, when Andrea C. Ferrari at the University of Cambridge (UK) and colleagues there and at the Polytechnic Institute of Turin (Italy) reported that a multivalley Fermi surface is associated with the superconductivity state in Molybdenum Disulfide (MoS2).

The authors believe that “this [Fermi surface] topology will serve as a guideline in the quest for new superconductors.”
Molybdenum Disulfide (MoS2) is an excellent material to be used for various industrial purposes.
However, Molybdenum Disulfide (MoS2)'s applications are so vast and diverse that they are being observed in various industries and are enhancing the credibility and productivity of the material itself.

Molybdenum disulfide belongs to a class of materials called 'transition metal dichalcogenides' (TMDCs).
Materials in this class have the chemical formula MX2, where M is a transition metal atom (groups 4-12 in the periodic table) and X is a chalcogen (group 16).

The chemical formula of molybdenum disulfide is MoS2.
Molybdenum Disulfide (MoS2) has been intensively studied for almost 10 years, and many potential applications have been investigated.
The crystal structure of molybdenum disulfide (MoS2) takes the form of a hexagonal plane of S atoms on either side of a hexagonal plane of Mo atoms.

These triple planes stack on top of each other, with strong covalent bonds between the Mo and S atoms, but weak van der Waals forcing holding layers together.
This allows them to be mechanically separated to form 2-dimensional sheets of Molybdenum Disulfide (MoS2).

Molybdenum Disulfide (MoS2) is a naturally occurring mineral that has gained significant attention for its unique properties and applications in various industries.
Molybdenum Disulfide (MoS2) is a compound that is structurally similar to graphite, with layers of molybdenum atoms sandwiched between layers of sulfur atoms.

This structure gives Molybdenum Disulfide (MoS2) excellent lubricating properties, high thermal stability, and strong chemical resistance, making it ideal for use in extreme conditions.
Its ability to operate efficiently under high pressure and temperature, coupled with its environmental friendliness, makes Molybdenum Disulfide (MoS2) a preferred choice in many advanced applications.

Following on from the huge research interest in graphene, Molybdenum Disulfide (MoS2) was the next 2-dimensional material to be investigated for potential device applications.
Due to its direct bandgap, Molybdenum Disulfide (MoS2) has a great advantage over graphene for several applications, including optical sensors and field-effect transistors.

Few-layer Molybdenum Disulfide (MoS2) is considered to be one of the most attractive materials for next-generation nanoelectronics.
This is due to Molybdenum Disulfide (MoS2)'s silicon-level charge mobility and high current on/off ratio in thin-film transistors.
Molybdenum Disulfide (MoS2) is the most famous of the single layer transition metal dichalcogenide (TMD) family.

Molybdenum Disulfide (MoS2) has been used in bulk for many years as a solid state lubricant, this is due to its low coefficient of friction in addition to its high chemical and thermal stability.
All forms of Molybdenum Disulfide (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 Molybdenum Disulfide (MoS2).
Bulk Molybdenum Disulfide (MoS2) consists of stacked monolayers, which are held together by weak van der Waals interactions.
Molybdenum Disulfide (MoS2) is a natural molybdenum sul-fide found in igneous rocks and metallic veins.

Molybdenum Disulfide (MoS2) is a two dimensional layered material. Monolayers of transition metal dichalcogenides (TMDs)exhibit photoconductivity.
The layers of the TMD can be mechanically or chemicaly exfoliated to form nanosheets.
Molybdenum Disulfide (MoS2) is a sulfide salt.

Molybdenite is a mineral with formula of Mo4+S2-2 or MoS2.
The IMA symbol is Mol.
Molybdenum Disulfide (MoS2) is a dry/solid lubricant powder, also known as the molybdenite (principal ore from which molybdenum metal is extracted), and has the chemical formula MoS2.

Molybdenum Disulfide (MoS2) is insoluble in water and dilute acids.
Crystal structure is Hexagonal Lamellar and is similar to graphite, Boron Nitride and Tungsten Disulfide.
Molybdenum Disulfide (MoS2) also has excellent film forming properties and is an excellent lubricant in moisture free environments below 400° C.

Molybdenum Disulfide (MoS2) offers excellent lubricity properties in inert atmospheres and under high vacuum where other conventional lubricants fail.
Molybdenum Disulfide (MoS2) also offers extreme pressure lubricant properties.
Molybdenum Disulfide (MoS2) is able to withstand up to 250,000 p.s.i. which makes it extremely effective when used in applications such as cold metal forming.

USES and APPLICATIONS of MOLYBDENUM DISULFIDE (MoS2):
Molybdenum Disulfide (MoS2) is used dry lubricant and lubricant additive.
Molybdenum Disulfide (MoS2) is used hydrogenation catalyst.
Molybdenum Disulfide (MoS2) is one of the most widely used lubricants in space systems.

Molybdenum Disulfide (MoS2) is a common additive that improves the antiseize properties of wheel bearing grease.
Molybdenum Disulfide (MoS2) has been used for many years as a solid lubricant because of its interesting friction-reducing properties related to its crystalline structure.

Molybdenum Disulfide (MoS2) is a lamellar compound made of a stacking of S-Mo-S layers .
In each of them, the molybdenum atom is surrounded by six sulfur atoms located at the top of a trigonal prism.
The distance between a molybdenum atom and a sulfur atom is equal to 0.241 nm, whereas the distance between two sulfur atoms from two adjacent layers is equal to 0.349 nm.

This characteristic was often used to explain easy cleavage between the layers and therefore the lubricating properties of Molybdenum Disulfide (MoS2).
In addition to serving as the primary natural source of molybdenum, purified molybdenum disulfide Molybdenum Disulfide (MoS2) is an excellent lubricant when in the form of a dry film, or as an additive to oil or grease.

Molybdenum Disulfide (MoS2) also is used as a filler in nylons, and as an effective catalyst for hydrogenation-dehydrogenation reactions.
Molybdenum Disulfide (MoS2) is often a component of blends and composites where low friction is sought.
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, Molybdenum Disulfide (MoS2) forms a composite with improved strength as well as reduced friction.
Polymers that have been flld with Molybdenum Disulfide (MoS2) include nylon (with the trade name Nylatron), Teflon, and Vespel.
Self-lubricating composite coatings for high-temperature applications have been developed consisting of Molybdenum Disulfide (MoS2) and titanium nitride by chemical vapor deposition.

Molybdenum Disulfide (MoS2) is often used in two-stroke engines; e.g. motorcycle engines.
Molybdenum Disulfide (MoS2) is also used in CV and universal joints.
Molybdenum Disulfide (MoS2)-coatings allow bullets easier passage through the rifle barrel causing less barrel fouling allowing the barrel to retain ballistic accuracy much longer.

This resistance to barrel fouling comes at a cost of lower muzzle velocity with the same load due to a decreased chamber pressure.
Molybdenum Disulfide (MoS2) is applied to bearings in ultra- high vacuum applications up to 10-9 torr (at -226 to 399 °C).
The lubricant is applied by burnishing and the excess is wiped from the bearing surface.

During the Vietnam War, the Molybdenum Disulfide (MoS2) product "Dri-Slide" was used to lubricate weapons, although it was supplied from private sources, not the military.
Molybdenum Disulfide (MoS2)-coatings allow bullets easier passage through the rifle barrel with less deformation and better ballistic accuracy.

As a result of its direct band-gap, single-layer Molybdenum Disulfide (MoS2) has received much interest for applications in electronic and optoelectronic devices (such as transistors, photodetectors, photovoltaics and light-emitting diodes).
Molybdenum Disulfide (MoS2) is often used in two-stroke engines; e.g., motorcycle engines.

Molybdenum Disulfide (MoS2) is also used in CV and universal joints.
Molybdenum Disulfide (MoS2) is also being explored for applications in photonics, and can be combined with other TMDCs to create advanced heterostructured devices.

Application Fields of Molybdenum Disulfide (MoS2): Secondary batteries‚field-effect transistors‚ sensors‚ organic light-emitting diodes‚ memory.
Molybdenum Disulfide (MoS2) is widely used as dry lubricant additive in Grease, Oils, Polymers, Paints and other coatings.
Molybdenum Disulfide (MoS2) is also used in ski wax to prevent static buildup in dry snow conditions and to add glide when sliding in dirty snow.

-Electronic applications of Molybdenum Disulfide (MoS2):
Molybdenum Disulfide (MoS2) has many promising peculiarities and one of them is that its bandgap has a non-zero value as compared to graphene.
Molybdenum Disulfide (MoS2) acts as a semiconductor and due to its conductivity that can be altered, MoS2 is both efficient and effective for electronic and logic devices.

Moreover, the indirect bandgap is contained by MoS2's bulk form which is then transformed at the nanoscale into a direct bandgap, suggesting that Molybdenum Disulfide (MoS2)'s single layer found application in the optoelectronic devices.

Low power electronic devices and short channel FETs are also a possibility by Molybdenum Disulfide (MoS2) because of its 2-dimensional structure as it gives us control over the material's electrostatic nature.

-Field-effect transistors uses of Molybdenum Disulfide (MoS2):
The most latest electronic devices have field-effect transistors as their most elementary part.
Semiconductor technology has evolved over time.

Lithography can particularly lessen the sizes of the transistor in the range of a few nanometres.
Their channel size is below 14 nm as compared to many advantages like cost reduction, low power consumption, and fast switching.
Quantum mechanical tunneling takes place between the source electrodes and the drain due to the Joule heating effect.

For avoiding short channel effects and producing nano-sized devices, exploring thinner channel materials and thinner gate oxides materials is very important.

The monolayer of Molybdenum Disulfide (MoS2) is a suitable material for switching nanodevices as it possesses a direct bandgap of 1.8 eV which is appreciable.

-Switchable transistor uses of Molybdenum Disulfide (MoS2):
A switchable transistor based on Molybdenum Disulfide (MoS2)'s monolayer was displayed firstly by Radisavljevic.
A semiconducting channel with 6.5 A˚ of thickness is contained by this device and a 30 nm thick layer of HfO2 is used to deposit this device on SiO2 substrate as it has been utilized for covering it and also working as a top-gated dielectric layer.

The current on/off ratio is displayed by this device at 108 room temperature.
Off-state current, for instance, the subthreshold slope of 74 mV/dec, and 100 fA is exhibited by this device.

According to this work, Molybdenum Disulfide (MoS2) has promising potential in flexible and transparent electronics, and that MoS2 is a good alternative for low standby power integrated circuits.

-Solid lubricants uses of Molybdenum Disulfide (MoS2):
When the liquid lubricants fail the requirements of the needed applications, then solid lubricants are used.
Oils, greases, and other liquid lubricants are not utilized in various applications because of their weight, sealing problems, and environmental conditions.

However, on the other side, as compared to systems that are based on grease lubrication, solid lubricants have less weight and are cheap.
In high vacuum conditions, the liquid lubricants cant work thus causing the device to be unfit as in these conditions, lubricants also get evaporated.

Decomposition or oxidization of liquid lubricants takes place at high-temperature conditions.
At cryogenic temperatures, liquid lubricants get viscous or solidify and are incapable of flowing.

-Liquid lubricants uses of Molybdenum Disulfide (MoS2):
When under the effect of radiation environment conditions and corrosive gas, the liquid lubricants start to decay.
Dust or other contaminants are easily taken by the liquid lubricants where the major problem is contamination.

The components that are associated with the liquid lubricants are very heavy so handling them in applications where there is a requirement of long storage, is difficult.
Thus, these problems are effectively dealt with by solid lubricants.

In all aspects, liquid lubricants fail when it comes to space mechanisms.
Antennas, rovers, telescopes, vehicles, and satellites, etc., are involved in the space moving systems.

In strict environmental conditions, these systems function for a longer period of time with little service.
In such environmental conditions, the promising choice is the solid lubricants, Molybdenum Disulfide (MoS2) specifically.

-In graphite contrast uses of Molybdenum Disulfide (MoS2):
Unlike graphite, Molybdenum Disulfide (MoS2) doesn’t need the water’s vapor pressure to exhibit lubrication.
Slip rings, gears, ball bearings, and pointing and releasing mechanisms, etc. are the components in the space applications that are dependent on Molybdenum Disulfide (MoS2) lubrication.

Molybdenum Disulfide (MoS2)'s lubricity declines over the effect of a humid environment exhibit a major challenge to its implementation in various terrestrial applications.

Molybdenum Disulfide (MoS2)'s sputtering with Ti involves the improvement of MoS2's mechanical characteristics and it also protects MoS2 against humidity.
This improvement in Molybdenum Disulfide (MoS2)'s mechanical characteristics is significant for dry machining operations.

-Biosensors uses of Molybdenum Disulfide (MoS2):
Serious health issues have significantly affected the lifestyle of the human.

Significant effects lead to the increase in the importance of finding new ways and techniques that can observe different and numerous factors that are causing those effects and diseases.

A significant and major role is played by the evolution of biosensors in this point of view.
There has also been the utilization of biosensing in some elementary ways for efficiently observing the disease-causing factors.

Sensitivity and selectivity are the two factors on which the quality of the biosensors depends.
The research is being done at a large scale for engineering the sensor matrices for the enhancement of the selectivity and sensitivity of the biosensors.

-Nanostructures uses of Molybdenum Disulfide (MoS2):
Molybdenum Disulfide (MoS2) Nanostructures that possess a 2D nature have been used for biosensing based on the electrochemical phenomenon.
There has been an extensive exploration of the Molybdenum Disulfide (MoS2)'s sheets in the form of electrode materials in biosensors.

Molybdenum Disulfide (MoS2) nanosheets display strong fluorescence in the visible range because of their direct bandgap, which makes MoS2 a suitable and appropriate candidate for optical biosensors.
Optical biosensors are cost-efficient.

1-D Molybdenum Disulfide (MoS2) displays promising electrical characteristics and is analog to carbon nanotubes (CNTs).
One of the efficient and effective candidates for biosensors is the electrochemical sensors that are based on carbon nanotubes.

-FET based biosensors uses of Molybdenum Disulfide (MoS2):
Many researchers are fascinated by FET-based biosensors.
A drain and two electrodes source are mainly contained by the FET and they electrically associate with each other via a channel that's based on the semiconductor material.

The current that's flowing through the channel between the drain snd the source is controlled by the third electrode, the gate that's coupled with a dielectric layer.

Biomolecules that create an electrostatic effect are captured by the functionalized channel and are then converted into an observable signal in the form of FET devices' electrical properties.
How the characteristics of the devices perform, depends on the gate's biasing strategy.

-Gas sensors uses of Molybdenum Disulfide (MoS2):
Right now, it is very much important to trace noxious gases and pollutants, for instance, sulfur dioxide (SO2), hydrogen sulfide (H2S), carbon dioxide (CO2), ammonia (NH3), and nitrogen oxide (NOx).

Environment, quality of air, and noxious gas are monitored by a way known as gas sensing.
Resistance dependence, field-effect transistor, chemiresistive, Schottky diode optical fibers, etc. and other various semiconductor gas sensors are used for gas sensing but because of their low cost of production and easy operation, the resistivity based gas sensors are the most appreciable one

-Evolution of Graphene and 2D Materials uses of Molybdenum Disulfide (MoS2):
It is because of their promising characteristics like high sensitivity, selectivity, large surface to mass ratio, and low noise, that the evolution of 2-dimensional materials and graphene helps in the research of gas sensors.

Observations were being made on the sensors' sensing behavior at different concentrations and various temperatures.
With a 4.6 ppb of detection limit, great sensitivity is showed by this sensor at 60 degrees Celsius temperature.
Complete recovery/fast response is showed by the sensor.

-Field-effect transistors uses of Molybdenum Disulfide (MoS2):
The large direct bandgap and relatively high carrier mobility in Molybdenum Disulfide (MoS2) make it an obvious choice for FETs.
Early experiments on single-layer Molybdenum Disulfide (MoS2) transistors showed great promise, with recorded mobilities of 200 cm2V-1s-1 and an on/off ratio of ~108.

Molybdenum Disulfide (MoS2) has been suggested that such devices may outperform silicon-based FETs in several key metrics, such as power efficiency and on/off ratio.

However, they tend to show only n-type characteristics.
Much effort has been applied to refining FETs through reducing substrate interactions, improving electrical injection and realising ambipolar transport.

-Photodetectors uses of Molybdenum Disulfide (MoS2):
The bandgap properties of Molybdenum Disulfide (MoS2) also lend themselves to optoelectronic applications.
A device fabricated from an exfoliated flake with sensitivity 880 AW-1 and broadband photoresponse (400-680nm) was first demonstrated 5 years ago.
By combining with graphene into a monolayer heterostructure, sensitivity has been enhanced by a factor of 104.

-Solar cells uses of Molybdenum Disulfide (MoS2):
Monolayer Molybdenum Disulfide (MoS2) has visible optical absorption that is an order of magnitude greater than silicon, making it a promising solar cell material.
When combined with monolayer WS2 or graphene, power conversion efficiencies of ~1% have been recorded.

While these efficiencies appear low, the active area of such devices only has a thickness of ~1 nanometer (compared to 100’s of micrometers for silicon cells), corresponding therefore to a 104 times increase in power density.
A type-II heterojunction cell consisting of CVD grown monolayer Molybdenum Disulfide (MoS2) and p-doped silicon has shown a PCE of over 5%.

-Chemical sensors uses of Molybdenum Disulfide (MoS2):
The photoluminescence (PL) intensity of monolayer Molybdenum Disulfide (MoS2) has been shown to be highly dependent on physical adsorption of water and oxygen onto its surface.
Electron transfer from the n-type monolayer to gas molecules stabilises excitons and increases the PL intensity by up to 100 times.

Other studies based on the electrical properties of FET structures have shown that monolayer based sensors are unstable when detecting NO, NO2, NH3 and humidity, but operation can be stabilised by using few-layers.
Sensitivities of <1ppm have been recorded for the case of NO.

-Supercapacitor electrodes uses of Molybdenum Disulfide (MoS2):
The most common crystal structure of Molybdenum Disulfide (MoS2) (2H) is semiconducting, which limits its viability for use as an electrode.
However, Molybdenum Disulfide (MoS2) can also form a 1T crystal structure which is 107 more conductive than the 2H structure.
Stacked 1T monolayers acting as electrodes in various electrolytic cells showed higher power and energy densities than graphene-based electrodes.

-Valleytronic devices uss of Molybdenum Disulfide (MoS2):
While still a technology in its infancy, there have been some early demonstrations of devices that operate on the principles of valleytronics.
Examples include a bi-layer Molybdenum Disulfide (MoS2) transistor with gate-tunable valley Hall effect and valley polarised light emitting devices.

-Nanoelectronics uses of Molybdenum Disulfide (MoS2):
Due to its semiconducting properties and tunable band gap, Molybdenum Disulfide (MoS2) has demonstrated significant potential in nanoelectronics, sensors, and biomedical fields.
For example, Molybdenum Disulfide (MoS2) monolayers have exhibited strong performance in 5 nm electronic devices.

These applications include 2D Molybdenum Disulfide (MoS2)-based field-effect transistors, which are used to develop operational amplifiers with an open-loop gain of approximately 36 dB at low frequencies.
Additionally, modern Molybdenum Disulfide (MoS2) photodetectors exhibit high efficiency, eliminating the need for complex fabrication methods.

-Flexible Electronics use of Molybdenum Disulfide (MoS2):
Molybdenum Disulfide (MoS2) has become a key material for flexible electronics thanks to its mechanical properties and electronic versatility.
Historically, the growth of Molybdenum Disulfide (MoS2) in rigid substrates posed challenges for its use in flexible applications.

However, recent advancements have enabled the development of high-quality Molybdenum Disulfide (MoS2) monolayers on ultrathin, flexible glass substrates with thicknesses below 40 µm.
Chemical vapor deposition is now a preferred method for synthesizing Molybdenum Disulfide (MoS2) for these applications, achieving optimized mobility of 9.1 cm2 V−1 s−1.5

These developments have reduced energy consumption and improved the performance of flexible devices, making Molybdenum Disulfide (MoS2) suitable for applications in flexible superconductors and electronics.

-Energy Storage uses of Molybdenum Disulfide (MoS2):
Molybdenum Disulfide (MoS2) has transformed the energy storage landscape, offering innovative solutions alongside graphene.
For example, Molybdenum Disulfide (MoS2)-based core-shell structures optimize energy performance by combining a functional core with a protective shell.

These structures enhance the electrochemical and catalytic properties of Molybdenum Disulfide (MoS2), making it a viable material for lithium-ion batteries, supercapacitors, and hydrogen evolution reactions.

Additionally, Molybdenum Disulfide (MoS2) nanocomposites paired with carbon and transition metal oxides are gaining traction for energy storage and conversion technologies.

-Biomedical Applications of Molybdenum Disulfide (MoS2):
Molybdenum Disulfide (MoS2) has shown potential in the biomedical field due to its biocompatibility and strong binding energy with biomolecules.
Molybdenum Disulfide (MoS2)-based nanostructures have been investigated for their ability to enhance drug delivery, refine bio-imaging techniques, support the development of sensitive biosensors, and enable advancements in photo-thermal therapy.

-New and future applications of Molybdenum Disulfide (MoS2):
Since the discovery of single-layer graphene in 2004, the field of 2D materials has seen several new classes of materials emerge.
One of these is transition metal dichalcogenides (TMDs).

These materials are comprised of one of the transition metals bound with one of the elements in Group 16.
However, oxides are typically not classed as dichalcogenides.
Molybdenum Disulfide (MoS2) is currently the most studied member of the TMD family.

Similar to graphite, when Molybdenum Disulfide (MoS2) transitions from a bulk structure to a single layer structure the properties of this material undergo a significant change.
The layers of the TMD can be mechanically or chemically exfoliated to form nanosheets.

The most striking change that occurs when transitioning from bulk to single layer is the shift in the optoelectronic properties, with the material changing from being an indirect bandgap semiconductor with a bandgap value of approximately 1.3 eV to a direct bandgap semiconductor with a bandgap value of approximately 1.9 eV.

Due to the presence of a bandgap in this material there are significantly more uses for Molybdenum Disulfide (MoS2) in comparison to other 2d materials such as graphene.

Some areas in which Molybdenum Disulfide (MoS2) has already been applied include high on/off ratio field effect transistors due to low leakage currents, memresistors based on layered TMD films, controllable spin and valley polarization, geometric confinement of excitons, tuneable photoluminescence, the electrolysis of water, and photovoltaics/photodetectors.

-Advanced Lubricants uses of Molybdenum Disulfide (MoS2):
Molybdenum Disulfide (MoS2) is used to create high-performance lubricants that offer superior lubrication under extreme conditions, such as high load, vacuum, and wide temperature ranges.
Molybdenum Disulfide (MoS2) is particularly valuable in precision machinery and space applications where traditional lubricants are inadequate.

-Electronics uses of Molybdenum Disulfide (MoS2):
Molybdenum Disulfide (MoS2) is utilized in the manufacture of transistors, photodetectors, and other electronic devices due to its semiconducting properties.
Molybdenum Disulfide (MoS2) is known for its thin-layer capabilities and effective electron mobility, which are crucial in the miniaturization of electronic components.

-Energy Conversion and Storage of Molybdenum Disulfide (MoS2):
Molybdenum Disulfide (MoS2) is employed in hydrogen evolution reactions as a catalyst, enhancing the efficiency of water splitting in hydrogen fuel production.
Molybdenum Disulfide (MoS2) is also explored for its potential in improving the efficiency and capacity of lithium-sulfur batteries.

-Catalysis uses of Molybdenum Disulfide (MoS2):
Molybdenum Disulfide (MoS2) is used as a catalyst in the petrochemical industry for the removal of sulfur from fuels.
Molybdenum Disulfide (MoS2)'s high surface area and active sites facilitate efficient catalytic reactions, contributing to cleaner and more efficient fuel technologies.

-Coatings and Polymer Additives uses of Molybdenum Disulfide (MoS2):
Molybdenum Disulfide (MoS2) is incorporated into various coatings to improve wear resistance and reduce friction.
Molybdenum Disulfide (MoS2) is also added to polymers to enhance their strength, thermal stability, and to provide UV protection properties, making it valuable in automotive and aerospace materials.

PROPERTIES OF MOLYBDENUM DISULFIDE (MoS2):
*Bulk properties
Molybdenum Disulfide (MoS2) occurs naturally as the mineral 'molybdenite'.
In its bulk form, Molybdenum Disulfide (MoS2) appears as a dark, shiny solid.

The weak interlayer interactions allow sheets to easily slide over one another, so Molybdenum Disulfide (MoS2) is often used as a lubricant.
Molybdenum Disulfide (MoS2) can also be used as an alternative to graphite in high-vacuum applications, but it does have a lower maximum operating temperature than graphite.

Bulk Molybdenum Disulfide (MoS2) is a semiconductor with an indirect bandgap of ~1.2eV, and is therefore of limited interest to the optoelectronics industry.

*Optical and electrical properties
Individual layers of Molybdenum Disulfide (MoS2) have radically different properties compared to the bulk.
Removing interlayer interactions and confining electrons into a single plane results in the formation of a direct bandgap with an increased energy of ~1.89eV (visible red).

A single monolayer of Molybdenum Disulfide (MoS2) can absorb 10% of incident light with energy above the bandgap.
When compared to a bulk crystal, a 1000-fold increase in photoluminescence intensity is observed, but it remains relatively weak - with a photoluminescence quantum yield of about 0.4%.

However, this can be dramatically increased (to over 95%) by removing defects that are responsible for non-radiative recombination.
The bandgap can be tuned by introducing strain into the structure.
A 300 meV increase in bandgap per 1% biaxial compressive strain applied to trilayer Molybdenum Disulfide (MoS2) has been observed.

The application of a vertical electric field has also been suggested as a method of reducing the bandgap in 2D TMDCs - potentially to zero, thereby switching the structure from semiconducting to metallic.
Photoluminescence spectra of Molybdenum Disulfide (MoS2) monolayers show two excitonic peaks: one at ~1.92eV (the A exciton), and the other at ~2.08eV (the B exciton).

These are attributed to the valence band splitting at the K-point (in the Brillouin zone) due to spin-orbit coupling, allowing for two optically active transitions.
The binding energy of the excitons is >500meV.

Hence, they are stable up to high temperatures.
Injecting excess electrons into Molybdenum Disulfide (MoS2) (by either electrical or chemical doping) can cause the formation of trions (charged excitons), which consist of two electrons and one hole.

They appear as peaks in the absorption and PL spectra, red-shifted by ~40meV with respect to the A exciton peak (tunable through doping concentration).
While the binding energy of trions is much lower than that of the excitons (at approximately 20meV), they have a non-negligible contribution to the optical properties of MoS2 films at room temperature.

Molybdenum Disulfide (MoS2) monolayer transistors generally display n-type behaviour, with carrier mobilities approximately 350cm2V-1s-1 (or ~500 times lower than graphene).
However, when fabricated into field-effect transistors, they can display massive on/off ratios of 108, making them attractive for high-efficiency switching and logic circuits.

MECHANICAL PROPERTIES OF MOLYBDENUM DISULFIDE (MoS2):
Mechanical properties
Molybdenum Disulfide (MoS2) monolayers are flexible, and thin-film FETs have been shown to retain their electronic properties when bent to a 0.75mm radius of curvature.

They have a stiffness comparable to steel, and a higher breaking strength than flexible plastics (such as polyimide(PI) and polydimethylsiloxane (PDMS)), making them particularly suitable for flexible electronics.
At around 35Wm-1K-1, the thermal conductivity of Molybdenum Disulfide (MoS2) monolayers is ~100 times lower than that of graphene

PROCESSING OF MONOLAYER MOLYBDENUM DISULFIDE (MoS2):
Various techniques have been utilized for the preparation of Molybdenum Disulfide (MoS2)’s monolayer films.
Here we have mentioned the most common techniques and a brief review of them.

*Mechanical Exfoliation
Mechanical exfoliation is also called the ‘Scotch-tape method’, and it was utilized for the first time for isolating the layers of graphene.
If you apply a sticky tape on a bulk crystal sample, it will lead to thin layers of crystal sticking to the tape once you peel the sticky tape off and it is because of its greater mutual adhesion as compared to the interlayer adhesion.

*Sticking and peeling process
Until the production of single monolayers, this sticking-and-peeling process repeats again and again.
Then, the single monolayers can be transferred on a substrate, for instance through a PDMS stamp.

This process forms crystalline monolayers of high quality that are capable of being more than 10's of microns in size, even though this process is with a low monolayer yield.
When it comes to TMDC research, this is the most preferred method of processing, despite the method being 'low-tech'.

*Solvent exfoliation
Sonication of bulk crystals takes place in an organic solvent, breaking them down into thin layers.
A distribution is obtained in the thickness and size of the layers, and a surfactant is also obtained which usually is added for stopping the restacking of the layers.

This method has a low monolayer yield and a high thin-film yield.
The sizes of the flakes are on a 100 nm of scale, making the flakes look small.

*Intercalation
Monolayers long Molybdenum Disulfide (MoS2)’s intercalation is classed as a form of solvent exfoliation at times.
In 1986, Molybdenum Disulfide (MoS2) was demonstrated for the first time.

A solution that functions as a lithium ions’ source (n-butyllithium commonly, which is dissolved in hexane) has bulk crystals placed in it, and those bulk crystals are diffusing between the layers of the crystal.
The addition of water is the next step and then the water forms an interaction with the lithium ions for producing hydrogen, which pushes the layers apart.

*Careful Control
Careful control should be done over the parameters of an experiment for obtaining a high monolayer yield in this method.
Less needed metallic 1T structure is possessed by the resulting layers instead of thesemiconducting 2H structure.

However, potential applications are observed for the 1T structure in the supercapacitor electrodes.
Thermal annealing can be used to convert the 1T structure to the 2H.

*Vapour Deposition
Mechanical exfoliation is not a scalable technique however it can give high crystalline monolayers.
A reliable and good large-scale method is needed to produced high-quality films if 2-dimensional materials are supposed to find applications in the field of optoelectronics.

Vapour deposition is one of the methods with such potential and that's why it is studied in depth.
A chemical reaction is involved in the chemical vapor deposition for converting s precursor to the final Molybdenum Disulfide (MoS2).
MoO3 is commonly annealed at a high temperature of 1000 degrees celsius for the production of the Molybdenum Disulfide (MoS2) films in sulfur's presence.

*Other Precursors
Ammonium thiomolybdate and molybdenum metal are the other precursors, and dip coating and e-beam evaporation are used to deposit these before they convert into a furnace.

In comparison with those that are made from the exfoliated layers, very low mobility is possessed by the FETs that are made from vapor-grown films.
Moreover, the quality, thickness, and size (generally 10’s nm to few microns), of the substrates and films choice.

PROPERTIES OF MOLYBDENUM DISULFIDE (MoS2):
*Bulk characteristics
Naturally, the occurrence of Molybdenum Disulfide (MoS2) is as a 'molybdenite' mineral.

The appearance of MoS2 in its bulk form is as a shiny, dark solid.
Molybdenum Disulfide (MoS2) is also utilized as a lubricant because the sheets can slide over one another easily due to their weak interlayer interactions.

Molybdenum Disulfide (MoS2) is also utilized in high-vacuum applications as an alternative to graphite, but its maximum operating temperature is lower as compared to the maximum operating temperature of graphite.
With ~1.2eV of an indirect bandgap, bulk Molybdenum Disulfide (MoS2) is a semiconductor and is thus of restricted interest to the optoelectronics industry.

*Electrical and Optical Characteristics
In comparison with the bulk, Molybdenum Disulfide (MoS2)'s layers have radically different characteristics.

Eliminating confining electrons and interlayer interactions into a single plane leads to the production of a direct bandgap with ~1.89eV (visible red) of increased energy.
10 percent of incident light with more than the energy of the bandgap can be absorbed by Molybdenum Disulfide (MoS2)'s single monolayer.

An increase of 1000 fold in photoluminescence intensity was observed in comparison with a bulk crystal, however, it stays comparatively weak, with about 0.4% of photoluminescence quantum yield.
Although, if we remove the defects that are the reasons for non-radiative combination then this can be increased in a dramatic fashion to over 95%.

*Bandgap
The introduction of strain into the structure can tune the bandgap.
There have been observations of a 300 meV increase in bandgap per 1% biaxial compressive strain applied to trilayer Molybdenum Disulfide (MoS2).

In 2-dimensional TMDCs, the bandgap can be reduced potentially to zero by applying vertical electric field as it has been considered as a method too, therefore switching the semiconducting structure to the metallic structure.

*Photoluminescence spectra
Two excitonic peaks are shown by the photoluminescence spectra of Molybdenum Disulfide (MoS2) monolayers: one peak is at ~1.92eV (the A exciton), and the other peak is at ~2.08eV (the B exciton).

Both of the peaks are because of the valence band splitting in the Brillouin zone at the K-point because of the spin-orbit coupling, which enables two optically active transitions.

More than 500 meV is the binding energy of the excitons.
Therefore, they are stable at high temperatures.

*Injection of Electrons
Trions can form on the injection of excess electrons through either chemical or electrical doping into Molybdenum Disulfide (MoS2).

Trions are charged excitons and they consist of one hole and two electrons.
The appearance of trions in the PL spectra and absorption is as peaks, red-shifted by ~40meV.

A non-negligible contribution is shared by the trions at room temperature to Molybdenum Disulfide (MoS2) film’s optical characteristics while the trion’s binding energy is way less as compared to the binding energy of excitons (at almost 20 meV).

*Transistors
N-type behavior is generally displayed by the Molybdenum Disulfide (MoS2) monolayer transistors, with almost 350cm2V-1s-1 (or ~500 times lower as compared to graphene) of carrier mobilities.

Although, they can exhibit massive on/off ratios of 108 when fabricated into field-effect transistors, making them efficient and attractive for highly efficient logic circuits and switching.

MECHANICAL PROPERTIES OF MOLYBDENUM DISULFIDE (MoS2):
It is shown that when bent to a 0.75 mm radius of curvature, thin-film FETs retain their electronic characteristics, proving that the Molybdenum Disulfide (MoS2) monolayers are flexible.

Their stiffness is the same as the steel, and they also have a higher breaking strength as compared to the breaking strength of flexible plastics like polydimethylsiloxane (PDMS) and polyimide (PI), leaving them specifically suitable and appropriate for flexible electronics.
As compared to graphene's thermal conductivity, the thermal conductivity of Molybdenum Disulfide (MoS2) monolayers is around 100 times less at around 35 Wm-1K-1.

*Valleytronics
A route to technologies beyond electronics is offered by the Molybdenum Disulfide (MoS2) and other 2-dimensional TMDCs, where degrees of freedom can be used for storing information or/and processing.

Molybdenum Disulfide (MoS2)’s electronic bandstructure exhibits the valence band's energy maxima, and conduction band's minima at Brillouin zone's both K and K' (often called -K) points.
The same energy gap is possessed by these two discrete 'valleys' but when it comes to position, they are discrete in the momentum space.

*Optical transitions
Angular momentum changes of -1 for the K’ point and +1 for the K-point need the optical transitions in these valleys.

Therefore, it is possible for excitons to be selectively excited into a valley with circularly polarised light - with excitons in the K’ region being excited by left-handed (σ-) polarized light and excitons in the K valley being excited by the right-handed (σ+) polarised light.

*Emission of light
Conversely, light that will emit from exciton recombination in the K’ valley will be σ- polarised, and light that will emit from exciton recombination in the K valley will be σ+ polarised.

Valley pseudospin, which is a degree of freedom, is represented by these valleys as they can be addressed independently, and valley pseudospin can also be utilized in valleytronic devices.

*Spin-orbit valence band
Moreover, for each of the valleys, opposite signs of spin are possessed by the spin-orbit split valence band at the K' and K points.

For instance, a spin-down hole and a spin-up electron make up an A-exciton in the K valley, and a spin-up hole and spin-down electron make up a K valley B-exciton.
The constituent charge carriers for B and A excitons in the K’ valley have the opposite spin.

PROMISINF CHARACTERISTICS OF MOLYBDENUM DISULFIDE (MoS2):
Excellent electrochemical characteristics, luminescence characteristics, and semiconducting characteristics are displayed by Molybdenum Disulfide (MoS2) as a remarkable probe for biosensing for observing several analytes.

A zero dimension, which is also called inorganic fullerenes, is displayed by the Molybdenum Disulfide (MoS2) quantum dots, and their size is in less than 10 nm of range.
Promising electric and catalytic characteristics are contained by Molybdenum Disulfide (MoS2) quantum dots.

High photoluminescence at specific wavelengths is exhibited by Mo2 quantum dots due to the quantum confinement effect, and those wavelengths make Molybdenum Disulfide (MoS2) efficient and effective for optical biosensing based on the fluorimetric method.

CRYSTALLINE STRUCTURE OF MOLYBDENUM DISULFIDE (MoS2):
Molybdenum disulfide's (MoS2) crystal structure takes the shape of S atoms' hexagonal plane on either of the side of Mo atoms' hexagonal plane.
There is strong covalent bonding between the S and Mo atoms, and these triple planes stack on each other's top, however, the weak Van Der Waals forcing holds the layers together, which allow the layers to be mechanically separated for forming Molybdenum Disulfide (MoS2)'s 2-dimensional sheets.

SYNTHESIS OF MOLYBDENUM DISULFIDE (MoS2):
The preparation of Molybdenum Disulfide (MoS2) was carried out through modification of the method described in literature.
All the chemicals were purchased and used as received.

To start, 30 mL of 0.008 M ammonium molybdate ((NH4)6Mo7O24·4H2O, Merck India, 98%) solution was taken, and sodium dodecyl sulfate (SDS) of 10 times of cmc (critical micelle concentration) was added to it under constant stirring to obtain a clear solution.

Then, 9.60 mL of 0.23 M sodium dithionite (Na2S2O4, BDH, England, 98% pure) solution and 45 mL of 0.20 M thioacetamide (CH3CSNH2, Spectrochem India, 99%) solution were added into the former solution and were thoroughly mixed together by stirring.
The solution mixture was heated (~90°C) over a water bath to obtain a clear reddish yellow color solution.

Acidification of this solution with concentrated HCl (pH < 1) led to a dark brown colored precipitate.
The precipitate was isolated using a centrifuge and was washed with water for several times.

Drying of the precipitate gave rise to brownish black powders, which were calcined at 400°C for 2 h under argon atmosphere to obtain the black powders of Molybdenum Disulfide (MoS2).

STRUCTURE AND HYDROGEN BONDING OF MOLYBDENUM DISULFIDE (MoS2):
Molybdenum Disulfide (MoS2) belongs to a class of materials called 'transition metal dichalcogenides' (TMDCs).
Materials in this class have the chemical formula MX2, where M is a transition metal atom (groups 4-12 in the periodic table) and X is a chalcogen (group 16).

The chemical formula of molybdenum disulfide is MoS2.
The crystal structure of Molybdenum Disulfide (MoS2) takes the form of a hexagonal plane of S atoms on either side of a hexagonal plane of Mo atoms.

These triple planes stack on top of each other, with strong covalent bonds between the Mo and S atoms, but weak van der Waals forcing holding layers together.

This allows them to be mechanically separated to form 2-dimensional sheets of Molybdenum Disulfide (MoS2).
Molybdenum Disulfide (MoS2) with particle sizes in the range of 1-100 μm is a common dry lubricant.

Few alternatives exist that can confer the high lubricity and stability up to 350 °C in oxidizing environments.
Sliding friction tests of Molybdenum Disulfide (MoS2) using a pin on disc tester at low loads (0.1-2 N) give friction coefficient values of <0.1.

COMPARED TO MONOLAYER OF MOLYBDENUM DISULFIDE (MoS2)?
Molybdenum Disulfide (MoS2) (which needs a deposition of an additional high-k dielectric layer such as HfO2), few-layer MoS2 can be operated on its own.
This makes Molybdenum Disulfide (MoS2) more appealing for fabricating transistors and other optoelectronic devices.

PREPARATION OF MOLYBDENUM DISULFIDE (MoS2):
Synthetic- Chemical Vapour Transport (CVT)

CHEMICAL PROPERTIES OF MOLYBDENUM DISULFIDE (MoS2):
Molybdenum Disulfide (MoS2) is a dark grey or black powder，
Molybdenum Disulfide (MoS2), the most common natural form of molybdenum, is extracted from the ore and then purified for direct use in lubrication.

Since Molybdenum Disulfide (MoS2) is of geothermal origin, it has the durability to withstand heat and pressure.
This is particularly so if small amounts of sulfur are available to react with iron and provide a sulfide layer which is compatible with Molybdenum Disulfide (MoS2) in maintaining the lubricating film.

SYNTHESIS OF MOLYBDENUM DISULFIDE (MoS2):
High quality Molybdenum Disulfide (MoS2) few-layer films were grown directly on the substrates (SiO2/Si and Sapphire) by chemical vapour deposition (CVD) method.
The films were later transferred to the desired substrates using wet chemical transfer process.

VALLEYTRONICS OF MOLYBDENUM DISULFIDE (MoS2):
Molybdenum Disulfide (MoS2) and other 2D TMDCs may offer a route to technologies beyond electronics, where degrees of freedom (other than charge) can be utilised for information storage and/or processing.

The electronic band structure of Molybdenum Disulfide (MoS2) displays energy maxima of the valence band, and minima of the conduction band at both the K and K’ (often called -K) points of the Brillouin zone.
These two discrete ‘valleys’ have the same energy gap but are discrete in position in momentum space.

The optical transitions in these valleys require angular momentum changes of +1 for the K-point, and -1 for the K’ point.
Hence, excitons can be selectively excited into a valley with circularly polarised light - with right-handed (σ+) polarised light exciting excitons in the K valley, and left-handed (σ-) polarised light exciting excitons in the K’ valley.

Conversely, light emitted from exciton recombination in the K valley will be σ+ polarised, and light emitted from exciton recombination in the K’ valley will be σ- polarised.

Since these valleys can be independently addressed, they represent a degree of freedom called 'valley pseudospin' that could be used in ‘valleytronic’ devices.
Furthermore, the spin-orbit split valence band at the K and K’ points has opposite signs of spin for each of the valleys.

For example, an A-exciton in the K valley consists of a spin-up electron and a spin-down hole, and a K valley B-exciton has a spin-down electron and spin-up hole.
For A and B excitons in the K’ valley, their constituent charge carriers have the opposite spin.

This means that the valley pseudospin and charge carrier spin degrees of freedom are coupled (spin-valley coupling), and the spin and valley properties of charge carriers can be selected optically - through choice of excitation polarisation (to choose the valley) and energy (to select the A or B exciton - and hence, the spin).

When an in-plane electric field is applied, excitons may become disassociated, with the carriers retaining their valley and spin characteristics.
Electrons (and holes) in opposing valleys will travel in opposite directions perpendicular to the field.

This is called the 'valley Hall effect', and could form the basis of future technologies, where more information can be encoded onto electrons because of these added degrees of freedom.

a) σ+ circularly polarised light incident on a monolayer of Molybdenum Disulfide (MoS2) excites charge carriers in the K-valley (orange spheres).
Light with energy degenerate with the A-exciton (red arrow) excites spin-up electrons and spin-down holes.

Conversely, light corresponding to the B-exciton (blue arrow) excites spin-down electrons and spin-up holes.
An in-plane electric field causes electrons to accumulate on one edge of the layer, and holes on the other.

b) σ- light excites charge carriers in the K’-valley (green) with opposite spins to those in the K-valley, with the charges also accumulating on opposite edges.

c) Linearly polarised light with energy degenerate with the A-exciton excites charges in both valleys, with carriers carrying the same spins collecting on the same layer edge.

d) A similar situation is realised following excitation with linearly polarised light degenerate with the B-exciton, with spins migrating to the opposite sides of the layer.
Excitons in Molybdenum Disulfide (MoS2) have a valley lifetime (the time they remain in their original valley before scattering out) of a few picoseconds.

In comparison, the valley lifetime of electrons is >100 nanoseconds, and holes may have an even longer lifetime.
This represents the time available to complete logic operations using the valley pseudospin, and should be as large as possible for practical applications.

PHYSICAL and CHEMICAL PROPERTIES of MOLYBDENUM DISULFIDE (MoS2):
Chemical formula: MoS2
Molar mass: 160.07 g/mol
Appearance: black/lead-gray solid
Density: 5.06 g/cm3
Melting point: 2,375 °C (4,307 °F; 2,648 K)
Solubility in water: insoluble
Solubility: decomposed by aqua regia, hot sulfuric acid, nitric acid
insoluble in dilute acids
Band gap: 1.23 eV (indirect, 3R or 2H bulk) ~1.8 eV (direct, monolayer)

Structure:
Crystal structure: hP6, P63/mmc, No. 194 (2H) hR9, R3m, No 160 (3R)
Lattice constant:
a = 0.3161 nm (2H), 0.3163 nm (3R),
c = 1.2295 nm (2H), 1.837 (3R)
Coordination geometry: Trigonal prismatic (MoIV) Pyramidal (S2−)
Thermochemistry:
Std molar entropy (S⦵298): 62.63 J/(mol K)
Std enthalpy of formation (ΔfH⦵298): -235.10 kJ/mol
Gibbs free energy (ΔfG⦵): -225.89 kJ/mol

Molecular Weight: 160.1 g/mol
Hydrogen Bond Donor Count: 0
Hydrogen Bond Acceptor Count: 2
Rotatable Bond Count: 0
Exact Mass: 161.849546 g/mol
Monoisotopic Mass: 161.849546 g/mol
Topological Polar Surface Area: 64.2Å²
Heavy Atom Count: 3
Formal Charge: 0
Complexity: 18.3

Isotope Atom Count: 0
Defined Atom Stereocenter Count: 0
Undefined Atom Stereocenter Count: 0
Defined Bond Stereocenter Count: 0
Undefined Bond Stereocenter Count: 0
Covalently-Bonded Unit Count: 1
Compound Is Canonicalized: Yes
Physical state. powder
Color: gray
Odor: No data available

Melting point/freezing point.
Melting point: 1.185 °C
Initial boiling point and boiling range: No data available
Flammability (solid, gas): No data available
Upper/lower flammability or explosive limits: No data available
Flash point: No data available
Autoignition temperature: No data available
Decomposition temperature: No data available
pH: No data available

Viscosity
Viscosity, kinematic: No data available
Viscosity, dynamic: No data available
Water solubility: No data available
Partition coefficient: n-octanol/water:
Not applicable for inorganic substances
Vapor pressure: No data available
Density: 5,060 g/cm3 at 15 °C
Relative density: No data available

Relative vapor density: No data available
Particle characteristics: No data available
Explosive properties: No data available
Oxidizing properties: none
Other safety information: No data available
Melting point: 2375 °C
density: 5.06 g/mL at 25 °C(lit.)
form: powder
color: Gray to dark gray or black

Specific Gravity: 4.8
Water Solubility: Soluble in hot sulfuric acid, and aquaregia.
Insoluble in water, concentrated sulfuric acid and dilute acid.
Merck: 146,236
Boiling point: 100°C (water)
Exposure limits ACGIH: TWA 10 mg/m3; TWA 3 mg/m3
NIOSH: IDLH 5000 mg/m3
Stability: Stable.
Incompatible with oxidizing agents, acids.
InChIKey: CWQXQMHSOZUFJS-UHFFFAOYSA-N
CAS DataBase Reference: 1317-33-5(CAS DataBase Reference)

EPA Substance Registry System: Molybdenum sulfide (MoS2) (1317-33-5)
Bandgap: 1.23 eV
Electronic properties: 2D Semiconductor
CBNumber:CB6238843
Molecular Formula:MoS2
Molecular Weight:160.07
MDL Number:MFCD00003470
MOL File:1317-33-5.mol
Melting point: 2375 °C
Densit: 5.06 g/mL at 25 °C(lit.)
solubility: insoluble in H2O; soluble in concentrated acid solutions

form: powder
color: Gray to dark gray or black
Specific Gravity: 4.8
Odor: odorless
Water Solubility: Soluble in hot sulfuric acid, and aquaregia.
Insoluble in water, concentrated sulfuric acid and dilute acid.
Merck: 14,6236
Boiling point: 100°C (water)
Exposure limits ACGIH: TWA 10 mg/m3; TWA 3 mg/m3
NIOSH: IDLH 5000 mg/m3
Stability: Stable.

Incompatible with oxidizing agents, acids.
InChIKey: CWQXQMHSOZUFJS-UHFFFAOYSA-N
CAS DataBase Reference: 1317-33-5(CAS DataBase Reference)
EWG's Food Scores: 1
FDA UNII: ZC8B4P503V
EPA Substance Registry System: Molybdenum sulfide (MoS2) (1317-33-5)
Bandgap: 1.23 eV
Electronic properties: 2D Semiconductor
CAS Number: 1317-33-5
Chemical Formula: MoS2
Molecular Weight: 160.07 g/mol
Bandgap: 1.23 eV

Preparation: Synthetic - Chemical Vapour Transport (CVT)
Structure: Hexagonal
Electronic Properties: 2D semiconductor
Melting Point: 2375 °C (lit.)
Colour: Black / Dark brown
Classification / Family: Transition metal dichalcogenides (TMDCs), 2D semiconductor materials,
Nano-electronics, Nano-photonics, Materials science
Compound Formula: MoS2
Molecular Weight: 160.07
Appearance: Black powder or solid in various forms

Melting Point: 1185 ° C (2165 ° F)
Boiling Point: N/A
Density: 5.06 g/cm3
Solubility in H2O: Insoluble
EC No.: 215-263-9
Pubchem CID: 14823
IUPAC Name: bis(sulfanylidene)molybdenum
SMILES: S=[Mo]=S
InchI Identifier: InChI=1S/Mo.2S
InchI Key: CWQXQMHSOZUFJS-UHFFFAOYSA-N

Storage Temperature: Ambient temperatures
Exact Mass: 161.849549
Monoisotopic Mass: 161.849549
Linear Formula: MoS2
MDL Number: MFCD00003470
CBNumber: CB6238843
Molecular Formula: MoS2
Molecular Weight: 160.07
MDL Number: MFCD00003470
MOL File: 1317-33-5.mol
Melting Point: 2375 °C
Density: 5.06 g/mL at 25 °C (lit.)

Solubility: Insoluble in H2O; soluble in concentrated acid solutions
Form: Powder
Color: Gray to dark gray or black
Specific Gravity: 4.8
Odor: Odorless
Water Solubility: Soluble in hot sulfuric acid, and aquaregia.
Insoluble in water, concentrated sulfuric acid, and dilute acid.
Crystal Structure: MoS2 type
Crystal System: Six sides
Merck: 14,6236
Boiling Point: 100°C (water)
Space Group: P63/mmc

Stability: Stable. Incompatible with oxidizing agents, acids.
InChIKey: CWQXQMHSOZUFJS-UHFFFAOYSA-N
CAS DataBase Reference: 1317-33-5 (CAS DataBase Reference)
EWG's Food Scores: 1
FDA UNII: ZC8B4P503V
EPA Substance Registry System: Molybdenum sulfide (MoS2) (1317-33-5)
Bandgap: 1.23 eV
Electronic Properties: 2D Semiconductor
CAS No.: 1317-33-5
EINECS No.: 215-263-9
Chemical Formula: MoS2
Molecular Weight: 160.07
Standard: Enterprise
Crystal Structure: Hexagonal Layered structure

Specification
Appearance: Dark gray or black powder
Assay (BN): 99.5% min
Moisture: 0.3% max.
Particle Size (D50): 500 nm
C: 220ppm
Fe: 150ppm
Si: 180ppm
P: 50ppm
S: 30ppm
Sb: 2ppm
Cd: 1ppm max.

FIRST AID MEASURES of MOLYBDENUM DISULFIDE (MoS2):
-Description of first-aid measures
*If inhaled
After inhalation:
Fresh air.
*In case of skin contact:
Take off immediately all contaminated clothing.
Rinse skin with water/ shower.
*In case of eye contact
After eye contact:
Rinse out with plenty of water.
Remove contact lenses.
*If swallowed
After swallowing:
Make victim drink water (two glasses at most).
Consult doctor if feeling unwell.
-Indication of any immediate medical attention and special treatment needed
No data available

ACCIDENTAL RELEASE MEASURES of MOLYBDENUM DISULFIDE (MoS2):
-Environmental precautions:
No special precautionary measures necessary.
-Methods and materials for containment and cleaning up:
Observe possible material restrictions.
Take up dry.
Dispose of properly.
Clean up affected area.

FIRE FIGHTING MEASURES of MOLYBDENUM DISULFIDE (MoS2):
-Extinguishing media:
*Suitable extinguishing media:
Use extinguishing measures that are appropriate to local circumstances and the
surrounding environment.
*Unsuitable extinguishing media:
For this substance/mixture no limitations of extinguishing agents are given.
-Further information:
Suppress (knock down) gases/vapors/mists with a water spray jet.

EXPOSURE CONTROLS/PERSONAL PROTECTION of MOLYBDENUM DISULFIDE (MoS2):
-Control parameters:
--Ingredients with workplace control parameters:
-Exposure controls:
--Personal protective equipment:
*Eye/face protection:
Use equipment for eye protection.
Safety glasses
*Skin protection:
Full contact:
Material: Nitrile rubber
Minimum layer thickness: 0,11 mm
Break through time: 480 min
Splash contact:
Material: Nitrile rubber
Minimum layer thickness: 0,11 mm
Break through time: 480 min
*Respiratory protection
Recommended Filter type: Filter type P1
-Control of environmental exposure:
No special precautionary measures necessary.

HANDLING and STORAGE of MOLYBDENUM DISULFIDE (MoS2):
-Conditions for safe storage, including any incompatibilities:
*Storage conditions:
Tightly closed.
Dry.

STABILITY and REACTIVITY of MOLYBDENUM DISULFIDE (MoS2):
-Reactivity:
No data available
-Chemical stability:
The product is chemically stable under standard ambient conditions (room temperature) .
-Possibility of hazardous reactions:
No data available
-Conditions to avoid:
no information available