
Terbium is a chemical element with the symbol Tb and atomic number 65. It is a silvery-white rare earth metal that is malleable, ductile and soft enough to be cut with a knife.
Terbium is used to dope calcium fluoride, calcium tungstate and strontium molybdate, materials that are used in solid-state devices, and as a crystal stabilizer of fuel cells which operate at elevated temperatures. As a component of Terfenol-D (an alloy which expands and contracts in magnetic field more than any other alloy), terbium is of use in actuators in sensors. Terbium oxide is used in green phosphors in fluorescent lamps. Terbium "green" phosphors (which fluoresce a brilliant lemon-yellow) are combined with divalent europium blue phosphors and trivalent europium red phosphors to provide the "trichromatic" lighting technology.
Characteristics[]
It is relatively stable in air as compared to other lanthanides. Terbium exists in two crystal allotropes with a transformation temperature of 1289 °C between them.
The terbium(III) cation is brilliantly fluorescent, in a bright lemon-yellow color that is the result of a strong green emission line in combination with other lines in the orange and red. The yttrofluorite variety of the mineral fluorite owes its creamy-yellow fluorescence in part to terbium. Terbium easily oxidizes, and is therefore used in its elemental form only for research purposes. Single Tb atoms have been isolated by implanting them into fullerene molecules.
Terbium has a simple ferromagnetic ordering at temperatures below 219 K. Above 219 K, it turns into a helical antiferromagnetic state in which all of the atomic moments in a particular basal plane layer are parallel, and oriented at a fixed angle to the moments of adjacent layers. This unusual antiferromagnetism transforms into a disordered paramagnetic state at 230 K.
Value[]
The base value of each unit of ranges between 8 and 36Ð per unit, with up to 3 units being found at any one time.
Presence on Mars: Rare
Martian Minerals | |
Group 1 | Group 2 | Group 3 | Group 4 | Group 5 | Group 6 | |
Group 4 | |Actininum | Areanetium | Borane | Carbon Tetrachloride | Dubnium | Dysprosium | Erbium | Europium | Ferrous Dixenate | |Gadollinium | Golgathium | Holmium | Holmium Sulfate | Iron Golgathide | Neodymium | Praseodymium | Promethium | |Protactinium | Rutherfordium | Samarium | Selenium Arsenide | Terbium | Thallium Titanide | Thulium | Uranium| |