Tantalum(III) chloride or tantalum trichloride is non-stoichiometric with a range of composition from TaCl_2.9 to TaCl_3.1 Anionic and neutral clusters containing Ta(III) chloride include a₆Cl₁₈sup>4− and a₆Cl₁₄H₂O)₄.

Formation

Tantalum(III) chloride is formed by reducing tantalum(V) chloride with tantalum metal. this is done by heating tantalum(III) chloride to 305 °C, passing the vapour over tantalum foil at 600°, and condensing the trichloride at 365 °C. If the condensing region is kept at too high a temperature, then TaCl_2.5 deposits instead. The trichloride can also be prepared by thermal decomposition of TaCl₄, with removal of volatile TaCl₅. TaCl₅ can be vapourised leaving behind TaCl₃. "

Salt-free reduction In chemistry, salt-free reduction describes methodology for reduction of metal halides by electron-rich trimethylsilyl reagents. Traditional reductions of metal halides are accomplished with alkali metals, a process that cogenerates alkali metal s ...

" of a toluene solution of TaCl₅ with 1,4-disilyl-cyclohexadiene in the presence of

ethylene Ethylene (IUPAC name: ethene) is a hydrocarbon which has the formula or . It is a colourless, flammable gas with a faint "sweet and musky" odour when pure. It is the simplest alkene (a hydrocarbon with carbon-carbon double bonds). Ethylene i ...

produces a complex of TaCl₃: :

Properties

Above 500 °C, TaCl₃ disproportionates further releasing TaCl₅. TaCl₃ is insoluble in room temperature water, or dilute acid, but dissolves in boiling water. A blue-green solution is formed.

Complexes

Tantalum(III) chloride can form complexes with some ligands as a monomer or dimer. Complexes include Ta(=C-CMe₃)(PMe₃)₂Cl₃, aCl₃(P(CH₂C₆H₅)₃THFsub>2μ-N₂ and aCl₃THF₂sub>2μ-N₂ (dinitrogen complexes). As a dimer, complexes include Ta₂Cl₆(SC₄H₈)₃ (SC₄H₈=tetrahydrothiophene). Ta₂Cl₆(SMe₂)₃, Ta₂Cl₆(thiane)₃ and Ta₂Cl₆(thiolane)₃ have a double bond between the two tantalum atoms, and two bridging chlorides, and a bridging ligand.

References

{{Reflist Tantalum compounds Chlorides Non-stoichiometric compounds