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{{chembox
| verifiedrevid = 434167925
|   Name = Tantalum(IV) sulfide
| ImageFile2 = Molybdenite-3D-balls.png
| ImageSize = 200px
|   ImageName = Tantalum(IV) sulfide
|   OtherNames = tantalum disulfide
| Section1 = {{Chembox Identifiers
|   CASNo_Ref = {{cascite|correct|??}}
| CASNo = 12143-72-5
| PubChem = 82945
| EINECS =
| InChI = 1S/2S.Ta
| SMILES = S=[Ta]=S
  }}
| Section2 = {{Chembox Properties
|   Formula = TaS<sub>2</sub>
|   MolarMass = 245.08 g/mol
|   Appearance = black crystals
|   Density = 6.86 g/cm³, solid
|   MeltingPt = 3000°C
|   BoilingPt =
|   Solubility =
  }}
| Section3 = {{Chembox Structure
|   CrystalStruct = hexagonal
  }}
| Section7 = {{Chembox Hazards
|   EUClass = not listed
  }}
}}

'''Tantalum(IV) sulfide''' is the [[inorganic compound]] with the formula [[Tantalum|Ta]][[Sulfide|S<sub>2</sub>]]. It is a layered compound with three-coordinate sulfide centres and trigonal prismatic metal centres. It is structurally similar to the more famous material [[molybdenum disulfide]], MoS<sub>2</sub>. TaS<sub>2</sub> is a semiconductor with d<sup>1</sup> electron configuration.

Although an obscure material otherwise, TaS<sub>2</sub> has been the subject of many studies because it is a versatile host for [[Intercalation (chemistry)|intercalation]] of electron donors.<ref>J. F. Revelli, "Tantalum Disulfide (TaS<sub>2</sub>) and Its Intercalation Compounds" Inorganic Syntheses 1995, volume 30, pp. 155. {{DOI|10.1002/9780470132616.ch32}}</ref>

TaS<sub>2</sub> is prepared by the high temperature reaction of powdered tantalum and sulfur. It is purified and crystallized by [[chemical vapor transport]] using [[iodine]] as the transporting agent:
:TaS<sub>2</sub> + 2 I<sub>2</sub> <math>\overrightarrow{\leftarrow}</math> TaI<sub>4</sub> + 2 S

The crystallographic structure of tantalum disulfide shows a number of complexities. One of its forms 1T-TaS<sub>2</sub> undergoes a number of phase transitions as a function of temperature. In the lowest temperature phase, the commensurate phase (below 180K) there is a commensurate [[superstructure (condensed matter)|superstructure]], known as a [[charge density wave]] (CDW), at an angle of 13.9 degrees relative to the lattice. In an incommensurate phase above 353K the wave is aligned with the lattice. Two more structures exist: a nearly commensurate one appears between 353K and 180K upon cooling. Upon warming a triclinic phase is first formed between 223K and 283K to revert to the nearly commensurate one at 283K. Both these phases have different superstructures.<ref>Scanning Tunneling Microscopy of Charge Density Wave Structure in Tantalum Disulfide
Thomson, Ruth Ellen
Thesis (PH.D.)--UNIVERSITY OF CALIFORNIA, BERKELEY, 1991.Source: Dissertation Abstracts International, Volume: 53-05, Section: B, page: 2385.</ref>

==References==
{{reflist}}

{{Tantalum compounds}}

[[Category:Sulfides]]
[[Category:Tantalum compounds]]
[[Category:Inorganic compound stubs]]


{{inorganic-compound-stub}}