Beryllium Oxalates

Beryllium oxalate trihydrate, BeC₂O₄.3H₂O, can be prepared by dissolving basic beryllium carbonate in rather more than an equivalent amount of oxalic acid. On crystallising, oxalic acid crystals separate first, then crystals of beryllium oxalate. Even after nine recrystallisations the latter contain occluded oxalic acid. In the sufficiently recrystallised product the neutralisation of the occluded acid by exactly enough basic beryllium carbonate produces the pure normal oxalate. It crystallises in orthorhombic crystals, is stable at room temperature, very soluble in water, acid in reaction, sharp and sweet in taste, and readily decomposed by heat. 100 c.c. water at 25° C. dissolve 63.2 grm.; oxalic acid dissolves it more readily.

At 100°-105° C. the trihydrate passes into the monohydrate, which is stable in dry air. It loses water slowly above 105° C. and rapidly towards 220° C. Decomposition begins near the latter temperature, and at 350° C. the salt is completely converted into the oxide.

Other oxalates, basic and acid, which have been described, apparently do not exist.