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Diammonium tetrafluoroberyllate is one of several salts of the tetrafluoroberyllate anion, in which four fluorine atoms are covalently bonded to a beryllium atom in a tetrahedral arrangement. The anion has also been prepared as salts of alkali metals, alkaline earths, transition metals, and many organic amines, some with varying degrees of hydration.
Also called ammonium beryllium fluoride, the salt is formed by dissolving beryllium hydroxide [Be(OH)2] in an aqueous solution of ammonium hydrogen fluoride [(NH4)HF2]. The aqueous solution is concentrated in an evaporative crystallizer to form the diammonium tetrafluoroberyllate salt. Its crystals are orthorhombic (shown) with a density of 1.71 g/mL. Like all beryllium-containing compounds, it is extremely toxic.
Diammonium tetrafluoroberyllate is used to produce beryllium fluoride (BeF2) glass by heating the salt to 鈮�1000 掳C. BeF2, in turn, can be used to make beryllium metal by reducing聽it with elemental聽magnesium at 1300 掳C. In the past several years, beryllium has been in short supply; in 2016, L. N. Malyutin and co-workers at Tomsk Polytechnic University (Russia) developed improved methods to on its way to making the metal.
Advanced materials manufacturers, such as Materion (Mayfield Heights, OH), use ammonium tetrafluoroberyllate to make their beryllium-containing products. Materion uses the synthetic route described above to make BeF2 and the metal.
In addition to being the precursor to the metal, BeF2 has applications in the nuclear energy industry. Beryllium metal produced from ammonium tetrafluoroberyllate was used to make the mirrors of the , which is 聽scheduled to be launched later this year.
Ammonium tetrafluoroberyllate hazard information*
| Hazard class** | GHS code and hazard statement | |
|---|---|---|
| Acute toxicity, oral, category 3 | H301鈥擳oxic if swallowed |  |
| Skin corrosion/irritation, category 2 | H315鈥擟auses skin irritation |  |
| Sensitization, skin, category 1 | H317鈥擬ay cause an allergic skin reaction | |
| Serious eye damage/eye irritation, category 2A | H319鈥擟auses serious eye irritation聽 | |
| Acute toxicity, inhalation, category 1 | H330鈥擣atal if inhaled聽 | |
| Specific target organ toxicity, single exposure, respiratory tract irritation, category 3 | H335鈥擬ay cause respiratory irritation | |
| Carcinogenicity, category 1A | H350鈥擬ay cause cancer by inhalation聽 |  |
| Specific target organ toxicity, repeated exposure, category 1 | H372鈥擟auses damage to organs through prolonged or repeated exposure | |
| Hazardous to the aquatic environment, long-term hazard | H411鈥擳oxic to aquatic life with long-lasting effects |  |
*Information acquired from online sources, not a specific safety data sheet.
**Globally Harmonized System (GHS) of Classification and Labeling of Chemicals.聽聽
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Ammonium tetrafluoroberyllate聽
fast facts
| CAS Reg. No. | 14874-86-3 |
nomenclature | Beryllate(2鈥�), tetrafluoro-, ammonium (1:2) |
| Empirical formula | H8BeF4N2 |
| Molar mass | 121.08 g/mol |
| Appearance | White crystals |
| Melting point | 280 掳C (dec.) |
| Water solubility | 323 g/L |
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