Selenium tetrafluoride

Selenium tetrafluoride  Error creating thumbnail: Unable to save thumbnail to destination

Identifiers

CAS Number

* 13465-66-2 Y

3D model (JSmol)

* Interactive image

ChEBI |

* CHEBI:30435 Y

ChemSpider |

* 109914 Y

PubChem CID

* 123311

UNII |

* 73U0ARO564 Y

InChI

* InChI=1S/F4Se/c1-5(2,3)4 Y

Key: PMOBWAXBGUSOPS-UHFFFAOYSA-N Y

* InChI=1/F4Se/c1-5(2,3)4

Key: PMOBWAXBGUSOPS-UHFFFAOYAQ

SMILES

* F[Se](F)(F)F

Properties

Chemical formula

| SeF4
Molar mass | 154.954 g/mol
Appearance  | colourless liquid
Density | 2.77 g/cm3
Melting point |  −13.2 °C (8.2 °F; 259.9 K)
Boiling point |  101 °C (214 °F; 374 K)
Hazards
NFPA 704 (fire diamond)  |

~~W~~

Related compounds

Other anions

| selenium dioxide, selenium(IV) chloride, selenium(IV) bromide

Other cations

| sulfur tetrafluoride, tellurium(IV) fluoride

Related compounds

| selenium difluoride, selenium hexafluoride

Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

N verify (what is YN ?)
Infobox references

Selenium tetrafluoride (SeF4) is an inorganic compound. It is a colourless liquid that reacts readily with water. It can be used as a fluorinating reagent in organic syntheses (fluorination of alcohols, carboxylic acids or carbonyl compounds) and has advantages over sulfur tetrafluoride in that milder conditions can be employed and it is a liquid rather than a gas.

## Contents

* 1 Synthesis
* 2 Structure and bonding
* 3 Reactions
* 4 References
* 5 See also
* 6 External links

## Synthesis

The first reported synthesis of selenium tetrafluoride was by Paul Lebeau in 1907, who treated selenium with fluorine:[1]

Se + 2 F2 → SeF4

A synthesis involving more easily handled reagents entails the fluorination of selenium dioxide with sulfur tetrafluoride:[2]

SF4 \+ SeO2 → SeF4 \+ SO2

An intermediate in this reaction is seleninyl fluoride (SeOF2).

Other methods of preparation include fluorinating elemental selenium with chlorine trifluoride:

3 Se + 4 ClF3 → 3 SeF4 \+ 2 Cl2

## Structure and bonding

Selenium in SeF4 has an oxidation state of +4. Its shape in the gaseous phase is similar to that of SF4, having a see-saw shape. VSEPR theory predicts a pseudo-trigonal pyramidal disposition of the five electron pairs around the selenium atom. The axial Se-F bonds are 177 pm with an F-Se-F bond angle of 169.2°. The two other fluorine atoms are attached by shorter bonds (168 pm), with an F-Se-F bond angle of 100.6°. In solution at low concentrations this monomeric structure predominates, but at higher concentrations evidence suggests weak association between SeF4 molecules leading to a distorted octahedral coordination around the selenium atom. In the solid the selenium center also has a distorted octahedral environment.

## Reactions

In HF, SeF4 behaves as a weak base, weaker than sulfur tetrafluoride, SF4 (Kb= 2 X 10−2):

SeF4 \+ HF → SeF3+ \+ HF2−; (Kb = 4 X 10−4)

Ionic adducts containing the SeF3+ cation are formed with SbF5, AsF5, NbF5, TaF5, and BF3.[3] With caesium fluoride, CsF, the SeF5− anion is formed, which has a square pyramidal structure similar to the isoelectronic chlorine pentafluoride, ClF5 and bromine pentafluoride, BrF5.[4] With 1,1,3,3,5,5-hexamethylpiperidinium fluoride or 1,2-dimethylpropyltrimethylammonium fluoride, the SeF62− anion is formed. This has a distorted octahedral shape which contrasts to the regular octahedral shape of the analogous SeCl62−. [5]

## References

1. ↑ Paul Lebeau (1907). "Action of Fluorine on Selenium Tetrafluoride of Selenium". Comptes Rendus de l'Académie des Sciences de Paris 144: 1042.
2. ↑ Konrad Seppelt, Dieter Lentz, Gerhard Klöter "Selenium Tetrafluoride, Selenium Difluoride Oxide (Seleninyl Fluoride), and Xenon Bis[Pentafluorooxoselenate(VI)]" Inorg. Synth., 1987, vol. 24, 27-31. doi:10.1002/9780470132555.ch9
3. ↑ R. J. Gillespie; A. Whitla (1970). "Selenium tetrafluoride adducts. II. Adducts with boron trifluoride and some pentafluorides". Can. J. Chem. 48 (4): 657–663. doi:10.1139/v70-106.
4. ↑ K. O. Christe; E. C. Curtis; C. J. Schack; D. Pilipovich (1972). "Vibrational Spectra and Force Constants of the Square-Pyramidal Anions SF5−, SeF5−, and TeF5−". Inorganic Chemistry 11 (7): 1679–1682. doi:10.1021/ic50113a046.
5. ↑ Ali Reza Mahjoub; Xiongzhi Zhang; Konrad Seppelt (1995). "Reactions of the Naked Fluoride Ion: Syntheses and Structures of SeF62− and BrF6−". Chemistry: A European Journal 1 (4): 261–265. doi:10.1002/chem.19950010410.

* Selenium: Inorganic Chemistry Krebs. B., Bonmann S., Eidenschink I.; Encyclopedia of Inorganic Chemistry (1994) John Wiley and Sons ISBN 0-471-93620-0

## See also

* Selenium hexafluoride
* Sulfur tetrafluoride
* Tellurium tetrafluoride

## External links

* WebBook page for SeF4

* v
* t
* e

Selenium compounds

Se(−II)|

* Ag2Se
* Al2Se3
* CaSe
* Se2−

Se(0,I)|

* Se3S5

Se(I)|

* Se2S6
* Se2Cl2
* C3H7NO2Se

Se(II)|

* SeS2

Se(IV)|

* SeCl4
* SeF4
* SeO2
* SeS2
* SeOBr2
* SeOCl2

Se(VI)|

* SeF6
* SeO3
* SeO2F2

* v
* t
* e

Fluorine compounds

| HF |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | He

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LiF | BeF2 |  |  |  |  |  |  |  |  |  |  | BF3
B2F4 | CF4 | NF3 | OF2 | F− | Ne
NaF | MgF2 |  |  |  |  |  |  |  |  |  |  | AlF3 | SiF4 | PF3
PF5 | SF2
SF4
SF6 | ClF
ClF3
ClF5 | Ar
KF | CaF2 | ScF3 | TiF3
TiF4 | VF3
VF4
VF5 | CrF2
CrF3
CrF4
CrF5 | MnF2
MnF3 | FeF2
FeF3 | CoF2
CoF3 | NiF2 | CuF
CuF2 | ZnF2 | GaF3 | GeF4 | AsF3
AsF5 | SeF4
SeF6 | BrF3
BrF5 | KrF2
RbF | SrF2 | YF3 | ZrF4 | NbF4
NbF5 | MoF5
MoF6 | TcF6 | RuF3
RuF4
RuF5
RuF6 | RhF6 | PdF2 | AgF
AgF2
Ag2F | CdF2 | InF3 | SnF2
SnF4 | SbF3
SbF5 | TeF4 | IF
IF3
IF5
IF7 | XeF2
XeF4
XeF6
CsF | BaF2 | *  | HfF4 | TaF5 | WF4
WF6 | ReF4
ReF5
ReF6
ReF7 | OsF4
OsF5
OsF6 | IrF3
IrF5
IrF6 | PtF4
PtF6 | AuF3
Au2F10
AuF5·F2
| HgF2
Hg2F2 | TlF
TlF3 | PbF2
PbF4 | BiF3
BiF5 | Po | At | RnF2
Fr | Ra | **  | Rf | Db | Sg | Bh | Hs | Mt | Ds | Rg | Cn | Nh | Fl | Mc | Lv | Ts | Og
|  | ↓ |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
| * | LaF3 | CeF3 | Pr | NdF3 | PmF3 | SmF3
| Eu | Gd | Tb | DyF3 | Ho | Er | Tm | YbF3
| Lu |
| ** | AcF3 | ThF4 | Pa | UF3
UF4
UF5
UF6 | NpF3
NpF4
NpF5
NpF6
| PuF3
PuF4
PuF5
PuF6 | AmF3
AmF4 | CmF3 | Bk | Cf | Es | Fm | Md | No | Lr |

Other|

* AgBF4
* AgPF6
* Cs2AlF5
* K3AlF6
* Na3AlF6
* KAsF6
* LiAsF6
* NaAsF6
* HBF4
* KBF4
* LiBF4
* NaBF4
* RbBF4
* Ba(BF4)2
* Ni(BF4)2
* Pb(BF4)2
* Sn(BF4)2
* BaClF
* BaSiF6
* BaGeF6
* BrOF3
* BrO2F
* CBrF3
* CBr2F2
* CBr3F
* CClF3
* CCl2F2
* CCl3F
* CFN
* CF2O
* CF3I
* CHF3
* CH2F2
* CH3F
* C2Cl3F3
* C2H3F
* C6H5F
* C7H5F3
* C15F33N
* ClFO2
* CrFO4
* CrF2O2
* CsBF4
* NH4F
* FNO
* FNO2
* FNO3
* KHF2
* NaHF2
* ThOF2
* NH5F2
* (NH4)2SiF6
* F2OS
* F3OP
* PSF3
* HPF6
* HSbF6
* NH4PF6
* KPF6
* KSbF6
* LiPF6
* NaPF6
* NaSbF6
* Na2SiF6
* Na2TiF6
* Na2ZrF6
* TlPF6
* IOF3
* K2NbF7
* K2TaF7
* IO3F
* UO2F2

Chemical formulas

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