Beryllium carbonate

Beryllium carbonate is a chemical compound with the chemical formula BeCO3.
Structures.
There are three forms reported, anhydrous, a tetrahydrate and basic beryllium carbonate. The anhydrous form is reported to be unstable, decomposing to BeO and carbon dioxide, and requiring storage under CO2. The tetrahydrate is said to be formed when CO2 is bubbled through a solution of Be(OH)2 and is also reported to be similarly unstable.
Preparation.
Basic beryllium carbonate is a mixed salt, which can be prepared by the reaction of beryllium sulfate and ammonium carbonate, and contains both carbonate and hydroxide ions, with formula Be2CO3(OH)2. It is believed that in the older literature this is probably what was referred to as beryllium carbonate.
Safety.
It may cause irritation. Toxic. It should be handled carefully since several related beryllium compounds are known carcinogens.
Natural occurrence.
No purely beryllic carbonate is known to occur naturally. The only Be-rich carbonate mineral currently known is niveolanite.