Tungsten dichloride dioxide
{{chembox
| Verifiedfields = changed
| Watchedfields = changed
| verifiedrevid = 428738669
| Name = Tungsten dichloride dioxide
| ImageFile = WO2Cl2distances.png
| ImageName = Tungsten(VI) dioxydichloride
| IUPACName = Tungsten(VI) dichloride dioxide
| OtherNames = {{ubl|Tungsten(VI) dioxydichloride|Tungsten dichloride dioxide|Tungstyl chloride}}
| Section1 = {{Chembox Identifiers
| CASNo_Ref = {{cascite|correct|??}}
| CASNo = 13520-76-8
| ChemSpiderID = 10652408
| PubChem = 19092009
| EINECS = 236-862-1
| InChI = 1S/2ClH.2O.W/h2*1H;;;/q;;2*-2;/p-2
| StdInChI=1S/2ClH.2O.W/h2*1H;;;/q;;2*-2;/p-2
| StdInChIKey = DVBXMVWZPVBSJY-UHFFFAOYSA-L
| SMILES = [O-2].[O-2].[Cl-].[Cl-].[W]
}}
| Section2 = {{Chembox Properties
| Formula = {{chem2|WO2Cl2}}
| W=1|O=2|Cl=2
| Appearance = Yellow-red crystals
| Density = 4.67 g/cm3
| MeltingPtC = 265
| BoilingPt = Sublimes at > 350 °C in vacuum
| Solubility = decomposes
| SolubleOther = slightly soluble in ethanol
}}
| Section3 = {{Chembox Structure
| CrystalStruct = orthorhombic
}}
| Section7 = {{Chembox Hazards
| GHSPictograms = {{GHS07}}
| GHSSignalWord = Warning
| HPhrases = {{H-phrases|315|319|335}}
| PPhrases = {{P-phrases|}}
}}
}}
Tungsten dichloride dioxide, or Tungstyl chloride is the chemical compound with the formula {{chem2|WO2Cl2|auto=1}}. It is a yellow-colored solid. It is used as a precursor to other tungsten compounds. Like other tungsten halides, {{chem2|WO2Cl2}} is sensitive to moisture, undergoing hydrolysis.
Preparation
{{chem2|WO2Cl2}} is prepared by ligand redistribution reaction from tungsten trioxide and tungsten hexachloride:
:{{chem2|2 WO3 + WCl6 → 3 WO2Cl2}}
Using a two-zone tube furnace, a vacuum-sealed tube containing these solids is heated to 350 °C. The yellow product sublimes to the cooler end of the reaction tube. No redox occurs in this process.{{cite book | author = Tillack, J. | title = Inorganic Syntheses | chapter = Tungsten Oxyhalides | journal = Inorg. Synth. | year = 1973 | volume = 14 | pages = 109–122 | doi = 10.1002/9780470132456.ch22 | isbn = 9780470132456 }} An alternative route highlights the oxophilicity of tungsten:{{cite journal |author1=Gibson, V. C. |author2=Kee, T. P. |author3=Shaw, A. | title = New, improved synthesis of the group 6 oxyhalides, W(O)Cl4, W(O)2Cl2 and Mo(O)2Cl2 | journal = Polyhedron | year = 1988 | volume = 7 | issue = 7 | pages = 579–80 | doi = 10.1016/S0277-5387(00)86336-6}}
:{{chem2|WCl6 + 2 ((CH3)3Si)2O → 3 WO2Cl2 + 4 (CH3)3SiCl}}
This reaction, like the preceding one, proceeds via the intermediacy of {{chem2|WOCl4}}.
Structure
Gaseous tungsten dichloride dioxide is a monomer.{{cite journal |doi=10.1021/ic50070a020 |title=Synthesis and Structure of Four- and Five-Coordinated Gaseous Oxohalides of Molybdenum(VI) and Tungsten(VI) |year=1968 |last1=Ward |first1=Brian G. |last2=Stafford |first2=Fred E. |journal=Inorganic Chemistry |volume=7 |issue=12 |pages=2569–2573 }} Solid tungsten dichloride dioxide is a polymer consisting of distorted octahedral W centres. The polymer is characterized by two short W-O distances, typical for a multiple W-O bond, and two long W-O distances more typical of a single or dative W-O bond.Jarchow, O.; Schröder, F.; Schulz, H. "Kristallstruktur und Polytypie von WO2Cl2" Zeitschrift für anorganische und allgemeine Chemie 1968, vol. 363, p. 345ff. {{doi|10.1002/zaac.19683630108}}
Related oxy halides
Tungsten forms a number of oxyhalides including Tungsten(VI) oxytetrachloride, {{chem2|WOCl3}}, {{chem2|WOCl2}}. The corresponding bromides ({{chem2|WOBr4}}, {{chem2|WOBr3}}, {{chem2|WOBr2}}) are also known as is {{chem2|WO2I2}}.Holleman, A. F.; Wiberg, E. Inorganic Chemistry Academic Press: San Diego, 2001. {{ISBN|0-12-352651-5}}.
Reactions
{{chem2|WO2Cl2}} is a Lewis acid, forming soluble adducts of the type {{chem2|WO2Cl2L2}}, where L is a donor ligand such as bipyridine and dimethoxyethane. Such complexes often cannot be prepared by depolymerization of the inorganic solid, but are generated in situ from {{chem2|WOCl4}}.K. Dreisch, C. Andersson, C. Stalhandske "Synthesis and structure of dimethoxyethane-dichlorodioxo-tungsten(VI)—a highly soluble derivative of tungsten dioxodichloride" Polyhedron 1991, volume 10, p. 2417. {{doi|10.1016/S0277-5387(00)86203-8}}