Diboron tetrafluoride

Chemical compound

Names

Preferred IUPAC name

Diboron tetrafluoride

Systematic IUPAC name

Tetrafluorodiborane(4)

Identifiers

CAS Number

13965-73-6

3D model (JSmol)

Interactive image

ChemSpider

123165

PubChem CID

139653

CompTox Dashboard (EPA)

DTXSID80161143

InChI

InChI=1S/B2F4/c3-1(4)2(5)6
Key: WUWOPJNIAKTBSJ-UHFFFAOYSA-N

SMILES

FB(F)B(F)F

Properties

Chemical formula

B₂F₄

Molar mass

97.61 g·mol⁻¹

Appearance

Colorless gas

Density

4.3 kg/m³ (gas)

Melting point

−56 °C (−69 °F; 217 K)

Boiling point

−34 °C (−29 °F; 239 K)

Thermochemistry

Heat capacity (C)

79.1 J/mol K

Std molar
entropy (S^⦵₂₉₈)

317.3 J/mol K

Std enthalpy of
formation (Δ_fH^⦵₂₉₈)

-1440.1 kJ/mol

Gibbs free energy (Δ_fG^⦵)

-1410.4 kJ/mol

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

Infobox references

Chemical compound

Diboron tetrafluoride is the inorganic compound with the formula (BF₂)₂. A colorless gas, the compound has a halflife of days at room temperature. It is the most stable of the diboron tetrahalides,^[1] and does not appreciably decompose under standard conditions.^[2]

Structure and bonding

Diboron tetrafluoride is a planar molecule with a B-B bond distance of 172 pm.^[1] Although it is electron-deficient, the unsaturated boron centers are stabilized by pi-bonding with the terminal fluoride ligands. The compound is isoelectronic with oxalate.

Synthesis and reactions

Diboron tetrafluoride can be formed by treating boron monofluoride with boron trifluoride at low temperatures, taking care not to form higher polymers.^[3] Alternatively, diboron tetrachloride can be fluorinated with antimony trifluoride.^[2]

Addition of diboron tetrafluoride to Vaska's complex was employed to produce an early example of a transition metal boryl complex:^[4]

2 B₂F₄ + IrCl(CO)(PPh₃)₂ → Ir(BF₂)₃(CO)(PPh₃)₂ + ClBF₂

Historical literature

Louis Trefonas and William N. Lipscomb (1958). "Crystal and Molecular Structure of Diboron Tetrafluoride, B₂F₄". J. Chem. Phys. 28 (1): 54–55. Bibcode:1958JChPh..28...54T. doi:10.1063/1.1744079.
Gayles, J. N.; Self, J. (1964). "Infrared Spectrum of Diboron Tetrafluoride in the Gaseous and Solid States". Journal of Chemical Physics. 40 (12): 3530–3539. Bibcode:1964JChPh..40.3530G. doi:10.1063/1.1725048.
A. K. Holliday; F. B. Taylor (1964). "Diboron tetrafluoride. Part II. Reactions with some oxides and organometallic compounds". J. Chem. Soc.: 2731–2734. doi:10.1039/JR9640002731.
Vernon H. Dibeler; Susan K. Liston (1968). "Mass-spectrometric study of photoionization. XII. Boron trifluoride and diboron tetrafluoride". J. Chem. Soc. 7 (9): 1742–1746. doi:10.1021/ic50067a010.

References

^ ^a ^b Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
^ ^a ^b Arthur Finch and Hermann Irving Schlesinger (1958). "Diboron Tetrafluoride". J. Am. Chem. Soc. 80 (14): 3573–3574. doi:10.1021/ja01547a020.
^ Timms, P. L. (1972). "Low Temperature Condensation of High Temperature Species as a Synthetic Method". Advances in Inorganic Chemistry and Radiochemistry. Academic Press: 143. doi:10.1016/S0065-2792(08)60006-0. ISBN 0-12-023614-1.
^ Neeve, Emily C.; Geier, Stephen J.; Mkhalid, Ibraheem A. I.; Westcott, Stephen A.; Marder, Todd B. (2016). "Diboron(4) Compounds: From Structural Curiosity to Synthetic Workhorse". Chemical Reviews. 116 (16): 9091–9161. doi:10.1021/acs.chemrev.6b00193. hdl:1807/78811. PMID 27434758.