Tantalum(V) fluoride

Chembox new
Name = Tantalum(V) fluoride
ImageFile = Tantalum(V) fluoride.jpg
ImageName = Tantalum(V) fluoride
OtherNames = tantalum pentafluoride
Section1 = Chembox Identifiers
CASNo = 7783-71-3
RTECS = WW5775000
Section2 = Chembox Properties
Formula = TaF₅
MolarMass = 275.95 g/mol
Appearance = white powder
Density = 4.74 g/cm³, solid
Solubility = decomposes
MeltingPt = 96.8 °C
BoilingPt = 229.5 °C
Section3 = Chembox Structure
Dipole = 0 D
Section7 = Chembox Hazards
EUClass = not listed
ExternalMSDS =
MainHazards = HF source
FlashPt = nonflammable
RPhrases = 34
SPhrases = 26-27-28-36/37/39-45
Section8 = Chembox Related
OtherCpds = TaCl₅
NbCl₅
WF₆

Tantalum(V) fluoride is the chemical compound with the formula. TaF₅. Characteristic of other penta and hexafluorides, TaF₅ is volatile.

Preparation

It is prepared by treating Ta metal with fluorine gas. [Priest, H. F. “Anhydrous Metal Fluorides” Inorganic Syntheses McGraw-Hill: New York, 1950; Vol. 3, pages 171-183.] NbF₅ is prepared similarly.

tructure

Solid and molten TaF₅ is tetrameric, consisting of four TaF₄ centers linked together via bridging fluoride atoms. Gaseous TaF₅ adopts the trigonal pyramidal structure, with D_3h symmetry. [Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-5.]

Reactions and derivatives

The tendency of TaF₅ to form clusters in the solid state indicates the Lewis acidity of the monomer. Indeed, TaF₅ reacts with fluoride sources to give the ions [TaF₆] ^-, [TaF₇] ^2-, and [TaF₈] ^3-. With neutral Lewis bases, such as diethyl ether TaF₅ forms adducts.

References