Beryllium bromide

Beryllium bromide is the chemical compound with the formula BeBr₂. It is very hygroscopic and dissolves well in water. The cation, which is relevant to BeBr₂, is characterized by the highest known charge density, making it one of the hardest cations and a very strong Lewis acid.

Preparation and reactions

It can be prepared by reacting beryllium metal with elemental bromine at temperatures of 500 °C to 700 °C:
When the oxidation is conducted on an ether suspension, one obtains colorless dietherate:
The same dietherate is obtained by suspending beryllium dibromide in diethyl ether:
This ether ligand can be displaced by other Lewis bases
Beryllium bromide hydrolyzes slowly in water:
BeBr₂ + 2 H₂O → 2 HBr + Be₂

Two forms of BeBr₂ are known. Both structures consist of tetrahedral Be²⁺ centers interconnected by doubly bridging bromide ligands. One form consist of edge-sharing polytetrahedra. The other form resembles zinc iodide with interconnected adamantane-like cages.

Beryllium compounds are toxic if inhaled or ingested.