It is an insoluble solid compound, BeO, hexagonal, r.d. 3.01, m.p 2530°C.

It occurs naturally as bromellite, and can be made by burning beryllium in oxygen or by the decomposition of beryllium carbonate or hydroxide.

It is an important amphoteric oxide, reacting with acids to form salts and with alkalis to form compounds known as beryllates.

It is used in the production of beryllium and beryllium-copper refractories, transistors and integrated circuits.