Ammonium tetrafluoroborate
| Names | |
|---|---|
| IUPAC name
Ammonium tetrafluoroborate
| |
| Other names
Ammonium fluoroborate
Azanium tetrafluoroborate | |
| Properties | |
| NH4BF4 | |
| 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 |
| Hazards | |
| 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.
Contents
Properties
Chemical
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.
Physical
Ammonium tetrafluoborate is a colorless crystalline solid, soluble in water.
Availability
It is sold by chemical suppliers.
Preparation
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
Projects
- 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
Handling
Safety
Ammonium tetrafluoroborate is toxic if ingested, as both boron and fluorides are harmful.
It is mentioned that it's corrosive to aluminium.[4]
Storage
In closed bottles.
Disposal
Best to try and recycle it.
References
- ↑ Roe, A., Org. React. 1949, 5, 193
- ↑ Moss, R. A.; Schueler, P. E.; Lee, T. B. K., Tetrahedron Lett. 1973, 2509. (b) Moss, R. A., J. Org. Chem. 1966, 31, 1082
- ↑ https://pubs.rsc.org/en/content/articlelanding/1989/C3/C39890001837
- ↑ 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
