Diboron tetrafluoride
Stick model of diboron tetrafluoride
Space-filling model of the diboron tetrafluoride molecule
Preferred IUPAC name
Diboron tetrafluoride
Systematic IUPAC name
3D model (JSmol)
  • InChI=1S/B2F4/c3-1(4)2(5)6
  • FB(F)B(F)F
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)
79.1 J/mol K
317.3 J/mol K
-1440.1 kJ/mol
-1410.4 kJ/mol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

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


  1. ^ a b Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
  2. ^ a b Arthur Finch and Hermann Irving Schlesinger (1958). "Diboron Tetrafluoride". J. Am. Chem. Soc. 80 (14): 3573–3574. doi:10.1021/ja01547a020.
  3. ^ 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.
  4. ^ 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.