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Terbium Compounds
Terbium compounds are Chemical compound, compounds formed by the lanthanide metal terbium (Tb). Terbium generally exhibits the +3 oxidation state in these compounds, such as in terbium(III) chloride, TbCl3, terbium(III) nitrate, Tb(NO3)3 and Tb(CH3COO)3. Compounds with terbium in the +4 oxidation state are also known, such as terbium(IV) oxide, TbO2 and BaTbF6. Terbium can also form compounds in the 0, +1 and +2 oxidation states. The trivalent terbium ion (Tb3+) is generally colorless in aqueous solution, and when it is irradiated by certain wavelengths of ultraviolet light (such as 254 nm or 365 nm) in solution or crystal form, it will emit green fluorescence. This property has given rise to applications in fields such as optics. The tetravalent terbium ion (Tb4+) is non-luminescent and its coexistence with Tb3+ will reduce the green emission of Tb3+. Properties of terbium compounds Chalcogenides Oxides Terbium has a variety of oxides. The most easily obtai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Luminescence Of Terbium Compounds
Luminescence is a spontaneous emission of radiation from an electronically or vibrationally excited species not in thermal equilibrium with its environment. A luminescent object emits ''cold light'' in contrast to incandescence, where an object only emits light after heating. Generally, the emission of light is due to the movement of electrons between different energy levels within an atom after excitation by external factors. However, the exact mechanism of light emission in vibrationally excited species is unknown. The dials, hands, scales, and signs of aviation and navigational instruments and markings are often coated with luminescent materials in a process known as ''luminising''. Types * Ionoluminescence, a result of bombardment by fast ions * Radioluminescence, a result of bombardment by ionizing radiation * Electroluminescence, a result of an electric current passed through a substance ** Cathodoluminescence, a result of a luminescent material being struck by electron ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
