Chemical Properties
Terbium oxide is a dark brown powder. slightly hygroscopic. Insoluble in water and alkaline solution, soluble in dilute acid. The aqueous suspension is alkaline and can absorb carbon dioxide in the air to form basic carbonate.
Terbium oxide is a functional material used to make metal terbium, magneto-optical glass, phosphors, magneto-optical storage materials, chemical additives, etc.
Uses
Terbium Oxide, also called Terbia, has important role as an activator for green phosphors used in color TV tubes. Meanwhile Terbium Oxide is also used in special lasers and as a dopant in solid-state devices. It is also frequently used as a dopant for crystalline solid-state devices and fuel cell materials. Terbium Oxide is one of the chief commercial Terbium compounds. Produced by heating the metal Oxalate,Terbium Oxide is then used in the preparation of other Terbium compounds.
Preparation
Terbium(III,IV) oxide Synthesis: Tetraterbium nitrate or terbium carbonate or terbium sulfate solution with sodium hydroxide to form terbium hydroxide precipitate, which is filtered and burned to obtain terbium oxide.
4Tb(OH)3+0.5O2→Tb4O7+6H2O
Tb4O7 is most often produced by ignition of the oxalate at or the sulfate in air.
Application
Terbium(III,IV) oxide acts as a precursor for the preparation of other terbium compounds. It is used as a redox catalyst in reactions involving oxygen. At high temperatures, it can liberate oxygen. It finds applications in the manufacture of glass, optical and ceramic. Nanoparticles of terbium oxide are used as analytical reagents for the determination of drugs in food.
Reactions
Terbium Oxide reacts with atomic oxygen to produce TbO2, but more convenient preparations are available.
Tb4O7 (s) + 6 HCl (aq) → 2 TbO2 (s) + 2 TbCl3 (aq) + 3 H2O (l)
Terbium oxide is heated with ammonium chloride to produce the ammonium salt of the pentachloride:
Tb4O7 + 22 NH4Cl → 4 (NH4)2TbCl5 + 7 H2O + 14 NH3
Purification Methods
Dissolve it in acid (e.g. perchloric acid), precipitate it as its oxalate and ignite the oxalate at 650o.
