Ammonium tetrafluoroborate

From Sciencemadness Wiki
Revision as of 19:21, 29 February 2020 by Mabus (Talk | contribs) (Created page with "{{Chembox | Name = Ammonium tetrafluoroborate | Reference = | IUPACName = Ammonium tetrafluoroborate | PIN = | SystematicName = | OtherNames = Ammonium fluoroborate<br>Azanium...")

(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Jump to: navigation, search
Ammonium tetrafluoroborate
IUPAC name
Ammonium tetrafluoroborate
Other names
Ammonium fluoroborate
Azanium tetrafluoroborate
Molar mass 104.85 g/mol
Appearance White crystalline solid
Odor Odorless
Density 1.871 g/cm3 (15 °C)
Melting point 220–230 °C (428–446 °F; 493–503 K) (sublimes)
Boiling point Decomposes
10.85 g/100 ml (-2.7 °C)
5.26 g/100 ml (-1.5 °C)
3.09 g/100 ml (-1.0 °C)
12.20 g/100 ml (0 °C)
25.0 g/100 ml (16 °C)
25.83 g/100 ml (25 °C)
44.09 g/100 ml (50 °C)
67.50 g/100 ml (75 °C)
98.93 g/100 ml (100 °C)
113.7 g/100 ml (108.5 °C)
Solubility Soluble in aq. NH3
Solubility in hydrogen fluoride 20% (0 °C)
Vapor pressure ~0 mmHg
Safety data sheet Sigma-Aldrich
Flash point Non-flammable
Related compounds
Related compounds
Nitronium tetrafluoroborate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Ammonium tetrafluoborate (NH4BF4) is a chemical compound, a primary source of the BF4 cation.



The BF4 anion is less nucleophilic and basic (and therefore more weakly coordinating) than nitrates, halides or even triflates. Thus, when using salts of BF4, one can usually assume that the cation is the reactive agent and this tetrahedral anion is inert.

When heated to decomposition it emits very toxic fumes of hydrogen fluoride, nitrogen oxides and ammonia.


Ammonium tetrafluoborate is a colorless crystalline solid, soluble in water.


It is sold by chemical suppliers.


Ammonium fluoroborate can be obtained by reacting boric acid with hydrofluoric acid and then with ammonium bicarbonate.

H3BO3 + 4 HF → HBF4 + 3 H2O
HBF4 + NH4HCO3 → NH4BF4 + H2O + CO2


  • Preparation of arenediazonium tetrafluoroborates[1]
  • Inversion of chiral amines[2]
  • Dealumination of zeolites[3]
  • Isolate highly electrophilic cations
  • Electrolyte useful for synthetic electrochemistry
  • Source of fluoride



Ammonium tetrafluoroborate is toxic if ingested, as both boron and fluorides are harmful.

It is mentioned that it's corrosive to aluminium.[4]


In closed bottles.


Best to try and recycle it.


  1. Roe, A., Org. React. 1949, 5, 193
  2. Moss, R. A.; Schueler, P. E.; Lee, T. B. K., Tetrahedron Lett. 1973, 2509. (b) Moss, R. A., J. Org. Chem. 1966, 31, 1082
  4. Association of American Railroads. Emergency Handling of Hazardous Materials in Surface Transportation. Washington, D.C.: Assoc. of American Railroads, Hazardous Materials Systems (BOE), 1987., p. 34

Relevant Sciencemadness threads