Beryllium Fluoride

Author: Hans Lohninger

Beryllium fluoride (BeF₂) is a white solid being used as the principal precursor for the manufacture of beryllium metal. The production of beryllium is done by the reduction of BeF₂ at 1300°C with magnesium in a graphite crucible:

BeF₂ + Mg Be + MgF₂

In order to obtain BeF₂ beryllium ores (mainly bertrandite) are converted into Be(OH)₂. The impure Be(OH)₂ then reacts with ammonium bifluoride to give ammonium tetrafluorberyllate:

Be(OH)₂ + 2 (NH₄)HF₂ (NH₄)₂BeF₄ + 2 H₂O

Tetrafluorberyllate is a robust ion, which allows its purification by precipitation of various impurities as their hydroxides. Heating purified (NH₄)₂BeF₄ gives the desired product:

(NH₄)₂BeF₄ 2 NH₃ + 2 HF + BeF₂