Terbium is a chemical element with the symbol Tb and atomic number 65. It is a silvery-white, rare earth metal that is bendable, (able to be flattened or drawn into wire), and soft enough to be cut with a knife. The ninth member of the lanthanide series, terbium is a fairly electropositive metal that reacts with water, changing (and getting better) hydrogen gas. Terbium is never found in nature as a free element, but it is contained in many minerals, including cerite, gadolinite, monazite, xenotime, and euxenite.
Swedish chemist Carl Gustaf Mosander discovered terbium as a chemical element in 1843. He detected it as a (dirt, dust, etc.) in yttrium oxide, Y2O3. Yttrium and terbium, as well as erbium and ytterbium, are named after the village of Ytterby in Sweden. Terbium was not (separated far from others) in (completely/complete, with nothing else mixed in) form until the coming of ion exchange ways of doing things.
Terbium is used to dope (silvery metal/important nutrient) fluoride, (silvery metal/important nutrient) tungstate and strontium molybdate, materials that are used in solid-state devices, and as a crystal (make steady/make firm and strong)r of (devices that make electricity from hydrogen) which operate at high/higher temperatures. As a part of Terfenol-D (a mix/mixture (of metals) that expands and contracts when exposed to magnetic fields more than any other mix/mixture (of metals)), terbium is of use in mechanical pushing-pulling devices, in naval sonar systems and in sensors.
Most of the world’s terbium supply is used in green phosphors. Terbium oxide is in fluorescent lamps and television and monitor cathode ray tubes (CRTs). Terbium green phosphors are combined with divalent europium blue phosphors and trivalent europium red phosphors to provide trichromatic lighting technology, a high-(wasting very little while working or producing something) white light used for standard lighting up/education in indoor lighting.
Terbium is a silvery-white rare earth metal that is bendable, (able to be flattened or drawn into wire) and soft enough to be cut with a knife. It is staying steady in air compared to the earlier, more (causing reactions from other people or chemicals) lanthanides in the first half of the lanthanide series. Terbium exists in two crystal give out/set asideropes with a change temperature of 1289 Â°C between them. The 65 electrons of a terbium atom are arranged in the electron setup [Xe]4f96s2; (usually/ in a common and regular way), only three electrons can be removed before the nuclear charge becomes too great to allow further ionization, but in the case of terbium, the (firm and steady nature/lasting nature/strength) of the half-filled [Xe]4f7 setup allows further ionization of a fourth electron in the presence of very strong oxidizing agents such as fluorine gas.
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 specifically for research. Single terbium atoms have been (separated far from others) by inserting 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 (next to) layers. This unusual antiferromagnetism changes into a (not working right/not acting right) paramagnetic state at 230 K.
Terbium metal is an electropositive element and oxidizes in the presence of most acids (such as sulfuric acid), all of the halogens, and even water.
2 Tb (s) + 3 H2SO4 a’ 2 Tb3+ + 3 SO2a’
4 + 3 H2a’
2 Tb + 3 X2 a’ 2 TbX3 (X = F, Cl, Br, I)
2 Tb (s) + 6 H2O a’ 2 Tb(OH)3 + 3 H2a’
Terbium also oxidizes easily in air to form a mixed terbium(III,IV) oxide:
8 Tb + 7 O2 a’ 2 Tb4O7
The most common oxidation state of terbium is +3 (trivalent), such as TbCl
3. In the solid state, tetravalent terbium is also known, in compounds such as TbO2 and TbF4. In solution, terbium usually forms trivalent (group of similar living things), but can be oxidized to the tetravalent state with ozone in highly basic water-based conditions.
The coordination and organometallic chemistry of terbium is just like other lanthanides. In water-based conditions, terbium can be coordinated by nine water molecules, which are arranged in a tricapped trigonal prismatic molecular geometry. Complexes of terbium with lower coordination number are also known, usually with (taking up a lot of space for its weight) ligands like bis(trimethyl-silylamide), which forms the three-coordinate Tb[N(SiMe3)2]3 complex.
Most coordination and organometallic complexes contain terbium in the trivalent oxidation state. Divalent (Tb2+) complexes are also known, usually with (taking up a lot of space for its weight) cyclopentadienyl-type ligands. A few coordination compounds containing terbium in its tetravalent state are also known.