Molybdenum diselenide

Top-view atomic images of MoSe2 before and after (right) ion irradiation[1]

Names
IUPAC name

bis(selanylidene)molybdenum

Other names

molybdenum diselenide, molybdenumdiselenide, molybdenum selenide, diselanylidenemolybdenum, molybdenum(IV) selenide

Identifiers

CAS Number

* 12058-18-3

3D model (JSmol)

* Interactive image

ECHA InfoCard | 100.031.831

PubChem CID

* 82894

CompTox Dashboard (EPA)

* DTXSID4065234

SMILES

* [Se]=[Mo]=[Se]

Properties

Chemical formula

| MoSe

Molar mass | 253.86 g/mol[2]
Appearance  | crystalline solid
Density | 6.90 g/cm3[2]
Melting point | >1200 °C[2]
Band gap | ~0.85 eV (indirect, bulk)
~1.5 eV (direct, monolayer)[3][4]
Structure

Crystal structure

| hP6, space group P6
3/mmc, No 194[5]

Lattice constant

a = 0.3283 nm, c = 1.2918 nm

Coordination geometry

| Trigonal prismatic (MoIV)
Pyramidal (Se2−)
Related compounds

Other anions

| Molybdenum dioxide
Molybdenum disulfide
Molybdenum ditelluride
Tantalum diselenide

Other cations

| Tungsten diselenide

Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Infobox references

Chemical compound

Molybdenum diselenide (MoSe
2) is an inorganic compound of molybdenum and selenium. Its structure is similar to that of MoS
2.[6] Compounds of this category are known as transition metal dichalcogenides, abbreviated TMDCs. These compounds, as the name suggests, are made up of a transition metals and elements of group 16 on the periodic table of the elements. Compared to MoS
2, MoSe
2 exhibits higher electrical conductivity.[7]

## Structure[edit]

Like many TMDCs, MoSe
2 is a layered material with strong in-plane bonding and weak out-of-plane interactions. These interactions lead to exfoliation into two-dimensional layers of single unit cell thickness.[8]

The most common form of these TMDCs have trilayers of molybdenum sandwiched between selenium ions causing a trigonal prismatic metal bonding coordination, but it is octahedral when the compound is exfoliated. The metal ion in these compounds is surrounded by six Se2−
ions. The coordination geometry of the Mo is sometimes found as octahedral and trigonal prismatic.[9]

## Synthesis[edit]

Synthesis of MoSe
2 involves direct reaction of molybdenum and selenium in a sealed tube at high temperature. Chemical vapor transport with a halogen (usually bromine or iodine) is used to purify the compound at very low pressure (less than 10-6 torr) and very high temperature (600–700 °C). It has to be heated very gradually to prevent explosion due to its strong exothermic reaction. Stoichiometric layers crystallize in a hexagonal structure as the sample cools.[9] Excess selenium can be removed by sublimation under vacuum.[10] The synthesis reaction of MoSe
2 is:

Mo + 2 Se → MoSe

### 2D-MoSe
2[edit]

Single-crystal-thick layers of MoSe
2 are produced by scotch tape exfoliation from bulk crystals or by chemical vapor deposition (CVD).[11][12]

The electron mobility of 2D-MoSe
2 is significantly higher than that of 2D-MoS
2. 2D MoSe
2 adopts structures reminiscent of graphene, although the latter's electron mobility is thousands of times greater still. In contrast to graphene, 2D-MoSe
2 has a direct band gap, suggesting applications in transistors and photodetectors.[11]

## Natural occurrence[edit]

Molybdenum(IV) selenide occurs in the nature as the extremely rare mineral drysdallite.[13]

## References[edit]

Wikimedia Commons has media related to Molybdenum diselenide.

1. ^ Iberi, Vighter; Liang, Liangbo; Ievlev, Anton V.; Stanford, Michael G.; Lin, Ming-Wei; Li, Xufan; Mahjouri-Samani, Masoud; Jesse, Stephen; Sumpter, Bobby G.; Kalinin, Sergei V.; Joy, David C.; Xiao, Kai; Belianinov, Alex; Ovchinnikova, Olga S. (2016). "Nanoforging Single Layer MoSe2 Through Defect Engineering with Focused Helium Ion Beams". Scientific Reports. 6: 30481. Bibcode:2016NatSR...630481I. doi:10.1038/srep30481. PMC 4969618. PMID 27480346.
2. ^ a b c Haynes, William M., ed. (2011). CRC Handbook of Chemistry and Physics (92nd ed.). Boca Raton, FL: CRC Press. p. 4.76. ISBN 1-4398-5511-0.
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. ^ Kioseoglou, G.; Hanbicki, A. T.; Currie, M.; Friedman, A. L.; Jonker, B. T. (2016). "Optical polarization and intervalley scattering in single layers of MoS2 and MoSe2". Scientific Reports. 6: 25041. arXiv:1602.00640. Bibcode:2016NatSR...625041K. doi:10.1038/srep25041. PMC 4844971. PMID 27112195.
5. ^ Agarwal, M. K.; Patel, P. D.; Joshi, R. M. (1986). "Growth conditions and structural characterization of MoSexTe2−x (0 ⩽ x ⩽ 2) single crystals". Journal of Materials Science Letters. 5: 66–68. doi:10.1007/BF01671439. S2CID 96858586.
6. ^ Greenwood, N. N.; Earnshaw, A. (11 November 1997). Chemistry of the Elements. Elsevier. pp. 1017–1018. ISBN 978-0-08-050109-3.
7. ^ Eftekhari, Ali (2017). "Molybdenum Diselenide (MoSe
2) for Energy Storage, Catalysis, and Optoelectronics". Applied Materials Today. 8: 1–16. doi:10.1016/j.apmt.2017.01.006.MoSe2)+for+Energy+Storage,+Catalysis,+and+Optoelectronics&rft.volume=8&rft.pages=1-16&rft.date=2017&rft_id=info:doi/10.1016/j.apmt.2017.01.006&rft.aulast=Eftekhari&rft.aufirst=Ali&rfr_id=info:sid/en.wikipedia.org:Molybdenum+diselenide" class="Z3988">
8. ^ Wang, Qing Hua; Kalantar-Zadeh, Kourosh; Kis, Andras; Coleman, Jonathan N.; Strano, Michael S. (2012). "Electronics and optoelectronics of two-dimensional transition metal dichalcogenides". Nature Nanotechnology. 7 (11): 699–712. Bibcode:2012NatNa...7..699W. doi:10.1038/nnano.2012.193. PMID 23132225. S2CID 6261931.
9. ^ a b Parilla, P.; Dillon, A.; Parkinson, B.; Jones, K.; Alleman, J.; Riker, G.; Ginley, D.; Heben, M; Formation of Nanooctahedra in Molybdenum Disulfide and Molybdenum Diselenide Using Pulsed Vapor Transport doi:10.1021/jp036202
10. ^ Al-hilli, A.; Evans, L. The Preparation and Properties of Transition Metal Dichalcogenide Single Crystals. Journal of Crystal Growth. 1972. 15, 93–101. doi:10.1016/0022-0248(72)90129-7
11. ^ a b "Scalable CVD process for making 2-D molybdenum diselenide". Rdmag.com. 2014-04-04. Retrieved 2014-04-09.
12. ^ Choi, H. M. T.; Beck, V. A.; Pierce, N. A. (2014). "Next-Generation in Situ Hybridization Chain Reaction: Higher Gain, Lower Cost, Greater Durability". ACS Nano. 8 (5): 4284–94. doi:10.1021/nn405717p. PMC 4046802. PMID 24712299.
13. ^ "Home". mindat.org.

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Molybdenum compounds

Mo(0)|

* Mo(CO)6

Mo(II)|

* MoBr2
* MoCl2
* MoSi2

Mo(III)|

* MoBr3
* MoCl3
* MoI3
* Mo2O3
* Mo2(OtBu)6

Mo(IV)|

* MoBr4
* MoCl4
* MoF4
* MoO2
* MoS2
* MoSe2
* MoTe2

Mo(V)|

* MoCl5
* MoF5
* Mo2O5

Mo(VI)|

* Molybdates
* Molybdic acid
* MoO3
* MoCl6
* MoOCl4
* MoO2Cl2
* MoF6
* MoS3
* MoAs2

* v
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Salts and covalent derivatives of the selenide ion

| H2Se
H2Se2 |  |  |  | He

|
|
|
|

Li2Se | Be  | SexByOz | CSe2
OCSe
(CH3)2Se | (NH4)2Se | O  | F  | Ne
Na2Se | MgSe | Al2Se3 | Si  | PxSey | +S | Cl  | Ar
K2Se | CaSe |  | Sc2Se3 | TiSe2 | V  | CrSe
Cr2Se3 | MnSe
MnSe2 | FeSe | CoSe | NiSe | CuSe | ZnSe | GaSe
Ga2Se3
-Ga | GeSe
GeSe2
-Ge | As2Se3
As4Se3 | Se2−
n | Br  | Kr
Rb2Se | SrSe |  | Y2Se3 | Zr  | NbSe2
NbSe3 | MoSe2 | Tc  | Ru  | Rh  | Pd  | Ag2Se | CdSe | In2Se3 | SnSe
SnSe2 | Sb2Se3 | Te  | +I | Xe
Cs2Se | BaSe | *  | Lu2Se3 | Hf  | TaSe2 | WSe2
WSe3 | ReSe2 | Os  | Ir  | PtSe2 | Au  | HgSe | Tl2Se | PbSe | Bi2Se3 | Po  | At  | Rn
Fr  | Ra  | **  | Lr  | Rf  | Db  | Sg  | Bh  | Hs  | Mt  | Ds  | Rg  | CnSe | Nh  | Fl  | Mc  | Lv  | Ts  | Og

*  | La2Se3 | CeSe
Ce2Se3 | Pr2Se3 | Nd2Se3 | Pm  | Sm2Se3 | EuSe
Eu2Se3 | Gd  | TbSe | Dy2Se3 | Ho2Se3 | Er2Se3 | Tm2Se3 | Yb
**  | Ac  | ThSe2 | Pa  | USe2 | Np  | PuSe | Am  | Cm  | Bk  | Cf  | Es  | Fm  | Md  | No
*[CID]: Compound ID
*[EPA]: U.S. Environmental Protection Agency
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