Tungsten diselenide information

Tungsten diselenide
	; WSe2 monolayer on graphene (yellow) and its atomic image (inset)
Identifiers
CAS Number	12067-46-8;
3D model (JSmol)	Interactive image;
ECHA InfoCard	100.031.877
EC Number	235-078-7;
PubChem CID	82910;
CompTox Dashboard (EPA)	DTXSID8065240 ;
	InChI InChI=1S/2Se.W Key: ROUIDRHELGULJS-UHFFFAOYSA-N;
	SMILES [Se]=[W]=[Se];
Properties
Chemical formula	WSe2
Molar mass	341.76 g/mol
Appearance	grey to black solid
Odor	odorless
Density	9.32 g/cm3
Melting point	> 1200 °C
Solubility in water	insoluble
Band gap	~1 eV (indirect, bulk); ~1.7 eV (direct, monolayer)
Structure
Crystal structure	hP6, space group P6; 3/mmc, No 194
Lattice constant	a = 0.3297 nm, c = 1.2982 nm
Coordination geometry	Trigonal prismatic (WIV); Pyramidal (Se2−)
Thermochemistry
Std enthalpy of; formation (ΔfH⦵298)	-185.3 kJ mol−1
Hazards
	Occupational safety and health (OHS/OSH):
Main hazards	External MSDS
Related compounds
Other anions	Tantalum diselenide
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Tungsten diselenide is an inorganic compound with the formula WSe₂.^[6] The compound adopts a hexagonal crystalline structure similar to molybdenum disulfide. The tungsten atoms are covalently bonded to six selenium ligands in a trigonal prismatic coordination sphere while each selenium is bonded to three tungsten atoms in a pyramidal geometry. The tungsten–selenium bond has a length of 0.2526 nm, and the distance between selenium atoms is 0.334 nm.^[7] It is a well studied example of a layered material. The layers stack together via van der Waals interactions. WSe₂ is a very stable semiconductor in the group-VI transition metal dichalcogenides.

^ Chiu, Ming-Hui; Zhang, Chendong; Shiu, Hung-Wei; Chuu, Chih-Piao; Chen, Chang-Hsiao; Chang, Chih-Yuan S.; Chen, Chia-Hao; Chou, Mei-Yin; Shih, Chih-Kang; Li, Lain-Jong (2015). "Determination of band alignment in the single-layer MoS₂/WSe₂ heterojunction". Nature Communications. 6: 7666. arXiv:1406.5137. Bibcode:2015NatCo...6.7666C. doi:10.1038/ncomms8666. PMC 4518320. PMID 26179885.
^ ^a ^b Agarwal, M. K.; Wani, P. A. (1979). "Growth conditions and crystal structure parameters of layer compounds in the series Mo_1−xW_xSe₂". Materials Research Bulletin. 14 (6): 825–830. doi:10.1016/0025-5408(79)90144-2.
^ Prakash, Abhijith; Appenzeller, Joerg (2017-02-28). "Bandgap Extraction and Device Analysis of Ionic Liquid Gated WSe2 Schottky Barrier Transistors". ACS Nano. 11 (2): 1626–1632. doi:10.1021/acsnano.6b07360. ISSN 1936-0851. PMID 28191930.
^ 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.
^ O'Hare, P.A.G.; Lewis, Brett M.; parkinson, B.A. (June 1988). "Standard molar enthalpy of formation by fluorine-combustion calorimetry of tungsten diselenide (WSe2). Thermodynamics of the high-temperature vaporization of WSe2. Revised value of the standard molar enthalpy of formation of molybdenite (MoS2)". The Journal of Chemical Thermodynamics. 20 (6): 681–691. doi:10.1016/0021-9614(88)90019-5.
^ Holleman, Arnold Frederik; Wiberg, Egon (2001), Wiberg, Nils (ed.), Inorganic Chemistry, translated by Eagleson, Mary; Brewer, William, San Diego/Berlin: Academic Press/De Gruyter, ISBN 0-12-352651-5
^ Schutte, W.J.; De Boer, J.L.; Jellinek, F. (1986). "Crystal Structures of Tungsten Disulfide and Diselenide". Journal of Solid State Chemistry. 70 (2): 207–209. Bibcode:1987JSSCh..70..207S. doi:10.1016/0022-4596(87)90057-0.

[1] Chiu, Ming-Hui; Zhang, Chendong; Shiu, Hung-Wei; Chuu, Chih-Piao; Chen, Chang-Hsiao; Chang, Chih-Yuan S.; Chen, Chia-Hao; Chou, Mei-Yin; Shih, Chih-Kang; Li, Lain-Jong (2015). "Determination of band alignment in the single-layer MoS₂/WSe₂ heterojunction". Nature Communications. 6: 7666. arXiv:1406.5137. Bibcode:2015NatCo...6.7666C. doi:10.1038/ncomms8666. PMC 4518320. PMID 26179885.

[str-2] Agarwal, M. K.; Wani, P. A. (1979). "Growth conditions and crystal structure parameters of layer compounds in the series Mo_1−xW_xSe₂". Materials Research Bulletin. 14 (6): 825–830. doi:10.1016/0025-5408(79)90144-2.

[3] Prakash, Abhijith; Appenzeller, Joerg (2017-02-28). "Bandgap Extraction and Device Analysis of Ionic Liquid Gated WSe2 Schottky Barrier Transistors". ACS Nano. 11 (2): 1626–1632. doi:10.1021/acsnano.6b07360. ISSN 1936-0851. PMID 28191930.

[4] 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.

[5] O'Hare, P.A.G.; Lewis, Brett M.; parkinson, B.A. (June 1988). "Standard molar enthalpy of formation by fluorine-combustion calorimetry of tungsten diselenide (WSe2). Thermodynamics of the high-temperature vaporization of WSe2. Revised value of the standard molar enthalpy of formation of molybdenite (MoS2)". The Journal of Chemical Thermodynamics. 20 (6): 681–691. doi:10.1016/0021-9614(88)90019-5.

[6] Holleman, Arnold Frederik; Wiberg, Egon (2001), Wiberg, Nils (ed.), Inorganic Chemistry, translated by Eagleson, Mary; Brewer, William, San Diego/Berlin: Academic Press/De Gruyter, ISBN 0-12-352651-5

[7] Schutte, W.J.; De Boer, J.L.; Jellinek, F. (1986). "Crystal Structures of Tungsten Disulfide and Diselenide". Journal of Solid State Chemistry. 70 (2): 207–209. Bibcode:1987JSSCh..70..207S. doi:10.1016/0022-4596(87)90057-0.

Tungsten diselenide information

and 28 Related for: Tungsten diselenide information

Tungsten diselenide

Diselenide

Transition metal dichalcogenide monolayers

Photocatalytic water splitting

Molybdenum diselenide

Tantalum diselenide

Tungsten disulfide

Niobium diselenide

Magnesium battery

Hubbard model

Chalcogenide

Liquid phase exfoliation

Molybdenum ditelluride

Tin selenide

Gilbert Daniel Nessim

Hafnium

Molybdenum disulfide

Silicon compounds

List of inorganic compounds

Germanium

Extreme tribology

Heterocumulene

Carbon group

Rhenium compounds

Selenium

Technetium

Lead

Oxidation state

Identifiers
WSe₂ monolayer on graphene (yellow) and its atomic image (inset)^[1]

CAS Number	12067-46-8
3D model (JSmol)	Interactive image
ECHA InfoCard	100.031.877
EC Number	235-078-7
PubChem CID	82910
CompTox Dashboard (EPA)	DTXSID8065240
InChI InChI=1S/2Se.W Key: ROUIDRHELGULJS-UHFFFAOYSA-N
SMILES [Se]=[W]=[Se]
Properties
Chemical formula	WSe₂
Molar mass	341.76 g/mol
Appearance	grey to black solid
Odor	odorless
Density	9.32 g/cm³^[2]
Melting point	> 1200 °C
Solubility in water	insoluble
Band gap	~1 eV (indirect, bulk)^[3] ~1.7 eV (direct, monolayer)^[4]
Structure
Crystal structure	hP6, space group P6 ₃/mmc, No 194^[2]
Lattice constant	a = 0.3297 nm, c = 1.2982 nm
Coordination geometry	Trigonal prismatic (W^IV) Pyramidal (Se²⁻)
Thermochemistry
Std enthalpy of formation (Δ_fH^⦵₂₉₈)	-185.3 kJ mol⁻¹^[5]
Hazards
Occupational safety and health (OHS/OSH):
Main hazards	External MSDS
Related compounds
Other anions	Tantalum diselenide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references