Tungsten(V) bromide

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Tungsten(V) bromide
WBr5.png
Crystal structure of tungsten(V) bromide
Names
Other names
tungsten pentabromide, tungsten(V) bromide, pentabromotungsten
Identifiers
3D model (JSmol)
ChemSpider
PubChem CID
  • InChI=1S/5BrH.W/h5*1H;/q;;;;;+5/p-5
    Key: UXVOMHPBSSIGNQ-UHFFFAOYSA-I
  • InChI=1S/5BrH.W/h5*1H;/q;;;;;+5/p-5
  • Br[W](Br)(Br)(Br)Br
Properties
WBr5, Br5W
Molar mass 583.4 g/mol
Appearancebrown-black crystals
hygroscopic
Melting point 286 °C (547 °F; 559 K)
Boiling point 333 °C (631 °F; 606 K)
+250.0·10−6 cm3/mol
Related compounds
Other anions
Tungsten(V) chloride
Other cations
Molybdenum(V) bromide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Tungsten(V) bromide is the inorganic compound with the empirical formula W Br5. The compound consists of bioctahedral structure, with two bridging bromide ligands, [1] so its molecular formula is W2Br10.

Contents

Preparation and structure

Tungsten(V) bromide is prepared by treating tungsten powder with bromine in the temperature range 650-1000 °C. The product is often contaminated with tungsten hexabromide. [2]

According to X-ray diffraction, the structure for tungsten pentabromide consists of an edge-shared bioctahedron. [1]

Reactions

Tungsten(V) bromide is the precursor to other tungsten compounds by reduction reactions. For example, tungsten(IV) bromide can be prepared by reduction with aluminium or tungsten. [2] The WBr4 can be purified by chemical vapor transport.

3 WBr5 + Al → 3 WBr4 + AlBr3

Excess tungsten pentabromide and aluminum tribromide are then removed by sublimation at 240 °C.

Tungsten(II) bromide can then be obtained heating the tetrabromide. [2] At 450-500 °C, gaseous pentabromide is evolved leaving yellow-green residue of WBr2. An analogous method can also be applied to the synthesis of tungsten(II) chloride.

Reductive substitution reactions

Because it is relatively easy to reduce tungsten pentahalides, they can be used as alternative synthetic routes to tungsten (IV) halide adducts. For example, reaction of WBr5 with pyridine gives WBr4(py)2. [2]

2 WBr5 + 7 C5H5N → 2 WBr4(C5H5N)2 + bipyridine + C5H5NHBr

Related Research Articles

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<span class="mw-page-title-main">Organotin chemistry</span> Branch of organic chemistry

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<span class="mw-page-title-main">Tantalum(V) chloride</span> Chemical compound

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<span class="mw-page-title-main">Methyllithium</span> Chemical compound

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<span class="mw-page-title-main">Tantalum(V) bromide</span> Chemical compound

Tantalum(V) bromide is the inorganic compound with the formula Ta2Br10. Its name comes from the compound's empirical formula, TaBr5. It is a diamagnetic, orange solid that hydrolyses readily. The compound adopts an edge-shared bioctahedral structure, which means that two TaBr5 units are joined by a pair of bromide bridges. There is no bond between the Ta centres. Niobium(V) chloride, niobium(V) bromide, niobium(V) iodide, tantalum(V) chloride, and tantalum(V) iodide all share this structural motif.

<span class="mw-page-title-main">Niobium(IV) chloride</span> Chemical compound

Niobium(IV) chloride, also known as niobium tetrachloride, is the chemical compound of formula NbCl4. This compound exists as dark violet crystals, is highly sensitive to air and moisture, and disproportiates into niobium(III) chloride and niobium(V) chloride when heated.

<span class="mw-page-title-main">Metal halides</span>

Metal halides are compounds between metals and halogens. Some, such as sodium chloride are ionic, while others are covalently bonded. A few metal halides are discrete molecules, such as uranium hexafluoride, but most adopt polymeric structures, such as palladium chloride.

<span class="mw-page-title-main">Molybdenum(III) chloride</span> Chemical compound

Molybdenum(III) chloride is the inorganic compound with the formula MoCl3. It forms purple crystals.

<span class="mw-page-title-main">Zirconium(III) bromide</span> Chemical compound

Zirconium(III) bromide is an inorganic compound with the formula ZrBr3.

<span class="mw-page-title-main">Zirconium(III) iodide</span> Chemical compound

Zirconium(III) iodide is an inorganic compound with the formula ZrI3.

Protactinium(V) bromide is an inorganic compound. It is a halide of protactinium, consisting of protactinium and bromine. It is radioactive and has a chemical formula of PaBr5, which is a red crystal of the monoclinic crystal system.

<span class="mw-page-title-main">Protactinium(IV) bromide</span> Chemical compound

Protactinium(IV) bromide is an inorganic compound. It is an actinide halide, composed of protactinium and bromine. It is radioactive, and has the chemical formula of PaBr4. It may be due to the brown color of bromine that causes the appearance of protactinium(IV) bromide to be brown crystals. Its crystal structure is tetragonal. Protactinium(IV) bromide is sublimed in a vacuum at 400 °C. The protactinium(IV) halide closest in structure to protactinium(IV) bromide is protactinium(IV) chloride.

Protactinium compounds are compounds containing the element protactinium. These compounds usually have protactinium in the +5 oxidation state, although these compounds can also exist in the +2, +3 and +4 oxidation states.

<span class="mw-page-title-main">Tungsten hexabromide</span> Chemical compound

Tungsten hexabromide, also known as tungsten(VI) bromide, is a chemical compound of tungsten and bromine with the formula WBr6. It is an air-sensitive dark grey powder that decomposes above 200 °C to tungsten(V) bromide and bromine.

<span class="mw-page-title-main">Tantalum(IV) iodide</span> Chemical compound

Tantalum(IV) iodide is an inorganic compound with the chemical formula TaI4. It dissolves in water to give a green solution, but the color fades when left in the air and produces a white precipitate.

References

  1. 1 2 Y.-Q. Zheng, K. Peters and H. G. von Schnering (1998) "Crystal structure of tungsten pentabromide, WBr5" Zeitschrift für Kristallographie - New Crystal Structures 213(3) 471
  2. 1 2 3 4 R.E. McCarley, T.M. Brown "The Preparation and Reactions of Some Tungsten (II) and Tungsten (IV) Halides" Inorg. Chem. 1964, volume 3, 1232-1236. doi : 10.1021/ic50019a007