Tantalum(V) fluoride is the inorganic compound with the formula TaF5. It is one of the principal molecular compounds of tantalum. Characteristic of some other pentafluorides, the compound is volatile but exists as an oligomer in the solid state.
It is prepared by treating tantalum metal with fluorine gas.[2] NbF5 is prepared similarly.
Solid and molten TaF5 is tetrameric, consisting of four TaF6 centers linked via bridging fluoride centers. Gaseous TaF5 adopts the trigonal pyramidal structure with D3hsymmetry.[3]
Reactions and derivativesedit
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 [TaF 6]− , [TaF 7]2− , and [TaF 8]3− . With neutral Lewis bases, such as diethyl ether TaF5 forms adducts.
TaF 5 is used in combination with HF as a catalyst for the alkylation of alkanes and alkenes and for the protonation of aromatic compounds. The TaF 5–HF system is stable in reducing environments, unlike SbF 5–HF.[4] In the presence of fluoride, tantalum pentafluoride forms the anions [TaF 8]3− , [TaF 7]2− , or [TaF 6]− , depending on the nature of the counterion and the concentration of HF. High concentrations of HF favor the hexafluoride by virtue of the formation of HF− 2:[5]
[TaF 7]2− + HF ⇌ [TaF 6]− + HF− 2
The salts M3TaF8 have been crystallized. For K+ = M+, the crystals consist of [TaF 7]2− anions together with fluoride that does not coordinate to Ta(V).[6] For M+ = M+, the crystals features [TaF 8]3− .[7]
Section of the Na3TaF8 structure (Ta = turquoise, F = green).
Relevance to separation of Ta and Nbedit
In the Marignac process, Nb and Ta are separated by fractional crystallization of K2TaF7 from solutions of hydrofluoric acid. Under these conditions, niobium forms K2NbOF5, which is more soluble than K2TaF7. Reduction of K2TaF7 with sodium gives metallic Ta.[8]
Referencesedit
^"Tantalum pentafluoride". pubchem.ncbi.nlm.nih.gov. Retrieved 16 December 2021.
^Priest, Homer F.; Swinehert, Carl F. (1950-01-01), Audrieth, Ludwig F. (ed.), "Anhydrous Metal Fluorides", Inorganic Syntheses, vol. 3 (1 ed.), Wiley, pp. 171–183, doi:10.1002/9780470132340.ch47, ISBN978-0-470-13162-6, retrieved 2024-01-22
^Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN0-12-352651-5.
^Arpad Molnar; G. K. Surya Prakash; Jean Sommer (2009). Superacid Chemistry (2nd ed.). Wiley-Interscience. p. 60. ISBN978-0-471-59668-4.
^Anatoly Agulyanski (2004). The chemistry of tantalum and niobium fluoride compounds. Amsterdam: Elsevier. p. 134. ISBN0-444-51604-2.
^Ľubomír Smrčok; Radovan Černý; Miroslav Boča; Iveta Macková; Blanka Kubíková (2010). "K3TaF8 from Laboratory X-ray powder data". Acta Crystallographica C. 66 (2): pi16–pi18. Bibcode:2010AcCrC..66I..16S. doi:10.1107/S0108270109055140. PMID 20124670.
^Langer, V.; Smrčok, L.; Boča, M. (2010). "Redetermination of Na3TaF8". Acta Crystallographica C. 66 (9): pi85–pi86. Bibcode:2010AcCrC..66I..85L. doi:10.1107/S0108270110030556. PMID 20814090.
^Klaus Andersson, Karlheinz Reichert, Rüdiger Wolf "Tantalum and Tantalum Compounds" in Ullmann's Encyclopedia of Industrial Chemistry 2002, Wiley-VCH. Weinheim. doi:10.1002/14356007.a26_071
January 01, 1970
tantalum, fluoride, inorganic, compound, with, formula, taf5, principal, molecular, compounds, tantalum, characteristic, some, other, pentafluorides, compound, volatile, exists, oligomer, solid, state, names, other, names, tantalum, pentafluoride, identifiers,. Tantalum V fluoride is the inorganic compound with the formula TaF5 It is one of the principal molecular compounds of tantalum Characteristic of some other pentafluorides the compound is volatile but exists as an oligomer in the solid state Tantalum V fluoride Names Other names tantalum pentafluoride Identifiers CAS Number 7783 71 3 Y 3D model JSmol Interactive image ChemSpider 74198 ECHA InfoCard 100 029 111 EC Number 232 022 3 PubChem CID 82218 RTECS number WW5775000 UNII QAG1W735WO Y CompTox Dashboard EPA DTXSID5064833 InChI Key YRGLXIVYESZPLQ UHFFFAOYSA IInChI 1S 5FH Ta h5 1H q 5 p 5 SMILES F Ta F F F F Properties Chemical formula TaF5 Molar mass 275 95 g mol Appearance white powder Density 4 74 g cm3 solid Melting point 96 8 C 206 2 F 369 9 K Boiling point 229 5 C 445 1 F 502 6 K Solubility in water decomposes Magnetic susceptibility x 795 0 10 6 cm3 mol Structure Dipole moment 0 D Hazards Occupational safety and health OHS OSH Main hazards HF source GHS labelling 1 Pictograms Signal word Danger Hazard statements H302 H314 Precautionary statements P260 P261 P264 P270 P271 P280 P301 P312 P301 P330 P331 P302 P352 P303 P361 P353 P304 P312 P304 P340 P305 P351 P338 P310 P312 P321 P322 P330 P363 P405 P501 Flash point Non flammable Related compounds Related compounds TaCl5NbCl5WF6 Except where otherwise noted data are given for materials in their standard state at 25 C 77 F 100 kPa Y verify what is Y N Infobox references Contents 1 Preparation and structure 2 Reactions and derivatives 2 1 Relevance to separation of Ta and Nb 3 ReferencesPreparation and structure editIt is prepared by treating tantalum metal with fluorine gas 2 NbF5 is prepared similarly Solid and molten TaF5 is tetrameric consisting of four TaF6 centers linked via bridging fluoride centers Gaseous TaF5 adopts the trigonal pyramidal structure with D3h symmetry 3 Reactions and derivatives editThe 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 TaF5 is used in combination with HF as a catalyst for the alkylation of alkanes and alkenes and for the protonation of aromatic compounds The TaF5 HF system is stable in reducing environments unlike SbF5 HF 4 In the presence of fluoride tantalum pentafluoride forms the anions TaF8 3 TaF7 2 or TaF6 depending on the nature of the counterion and the concentration of HF High concentrations of HF favor the hexafluoride by virtue of the formation of HF 2 5 TaF7 2 HF TaF6 HF 2 The salts M3TaF8 have been crystallized For K M the crystals consist of TaF7 2 anions together with fluoride that does not coordinate to Ta V 6 For M M the crystals features TaF8 3 7 nbsp Section of the Na3TaF8 structure Ta turquoise F green Relevance to separation of Ta and Nb edit In the Marignac process Nb and Ta are separated by fractional crystallization of K2TaF7 from solutions of hydrofluoric acid Under these conditions niobium forms K2NbOF5 which is more soluble than K2TaF7 Reduction of K2TaF7 with sodium gives metallic Ta 8 References edit Tantalum pentafluoride pubchem ncbi nlm nih gov Retrieved 16 December 2021 Priest Homer F Swinehert Carl F 1950 01 01 Audrieth Ludwig F ed Anhydrous Metal Fluorides Inorganic Syntheses vol 3 1 ed Wiley pp 171 183 doi 10 1002 9780470132340 ch47 ISBN 978 0 470 13162 6 retrieved 2024 01 22 Holleman A F Wiberg E Inorganic Chemistry Academic Press San Diego 2001 ISBN 0 12 352651 5 Arpad Molnar G K Surya Prakash Jean Sommer 2009 Superacid Chemistry 2nd ed Wiley Interscience p 60 ISBN 978 0 471 59668 4 Anatoly Agulyanski 2004 The chemistry of tantalum and niobium fluoride compounds Amsterdam Elsevier p 134 ISBN 0 444 51604 2 Ľubomir Smrcok Radovan Cerny Miroslav Boca Iveta Mackova Blanka Kubikova 2010 K3TaF8 from Laboratory X ray powder data Acta Crystallographica C 66 2 pi16 pi18 Bibcode 2010AcCrC 66I 16S doi 10 1107 S0108270109055140 PMID 20124670 Langer V Smrcok L Boca M 2010 Redetermination of Na3TaF8 Acta Crystallographica C 66 9 pi85 pi86 Bibcode 2010AcCrC 66I 85L doi 10 1107 S0108270110030556 PMID 20814090 Klaus Andersson Karlheinz Reichert Rudiger Wolf Tantalum and Tantalum Compounds in Ullmann s Encyclopedia of Industrial Chemistry 2002 Wiley VCH Weinheim doi 10 1002 14356007 a26 071 Retrieved from https en wikipedia org w index php title Tantalum V fluoride amp oldid 1206029961, wikipedia, wiki, book, books, library,
