Thulium metal

The rare metal thulium has almost no practical applications. What it can provide is available -more cheaply - from other lanthanides. It has been suggested, however, that the metal could be incorporated in ceramics, making them magnetic. If so, this material could be used in microwave equipment The y-radiation from the radioactive isotope °Tm has been examined for use in materials testing and as a portable X-ray source for medical use. 

The brittle, silvery, shiny metal was long considered the last stable element of the Periodic Table. In 2003 it was unmasked as an extremely weak alpha emitter (half-life 20 billion years). Like thulium, there is only one isotope. Bismuth alloys have low melting points (fuses, fire sprinklers). As an additive in tiny amounts, it imparts special properties on a range of metals. Applied in electronics and optoelectronics. The oxichloride (BiOCl) gives rise to pearlescent pigments (cosmetics). As bismuth is practically nontoxic, its compounds have medical applications. The basic oxide neutralizes stomach acids. A multitalented element. Crystallizes with an impressive layering effect (see right). 

Silver-colored, ductile metal that is attacked slowly by air and water. The element exhibits interesting magnetic properties. Found in television tubes. Laser material such as YAG (yttrium-aluminum garnet) doped with holmium (as well as chromium and thulium) can be applied in medicine, especially in sensitive eye operations. 

The silver gray metal can be cut with a knife, although it only melts at 1545 °C (for comparison, iron 1538 °C). It is the rarest of the "rare earths", but is nevertheless more abundant than iodine, mercury, and silver. Thulium has few applications, especially because it is relatively expensive. The element occurs naturally as a single isotope, namely 169Tm (compare bismuth). The artificial, radioactive 170Tm is a transportable source of X-rays for testing materials. Occasionally used in laser optics and microwave technology. 

Thulium is a naturally occurring rare metal that exists is very small amounts mixed with other rare-earths. It is a bright silvery metal that is malleable and ductile and can be cut easily with a knife. Its melting point is so high that it is difficult to force it into a melted state. Its vapor pressure is also high, and thus, much of the molten thulium evaporates into the atmosphere. Its melting point is 1,545°C, its boiling point is 2,950°C, and its density is 9.32g/cm. ... 

Thulium is near the end of the lanthanide series, where the metals tend to be heavier than the ones located near the beginning of the series. It is so scarce that it requires the processing of about 500 tons of earth to extract four kilograms of thulium. The only element that is scarcer is promethium, which is not found naturally on Earth. 

Thulium is relatively scarce and expensive, which hmits its commercial uses. Thulium-170, which is a radioactive isotope of thuhum produced by fission in nuclear reactors, can be used as small, portable X-ray sources. It also has limited use as an alloy metal with other metals and has experimentally been used in lasers. (Note Of all the isotopes of thuhum, only thuhum-169 is stable and nonradioactive.)... 

Soret and Delafontaine identified holmium in 1878 by examination of its spectrum. The following year, Cleve separated its oxide from Marignac s erbia, a mixture of erbium, holmium and thulium oxides. He named this element Holmium, after his native town Holmia (Stockholm). The metal was produced in 1934 by Klemm and Bommer. 

Holmium is obtained from monazite, bastnasite and other rare-earth minerals as a by-product during recovery of dysprosium, thulium and other rare-earth metals. The recovery steps in production of all lanthanide elements are very similar. These involve breaking up ores by treatment with hot concentrated sulfuric acid or by caustic fusion separation of rare-earths by ion-exchange processes conversion to halide salts and reduction of the hahde(s) to metal (See Dysprosium, Gadolinium and Erbium). 

Ionic radius Tm3+ 0.880 A. Metallic radius 1.746 A. First ionization potential 6.18 V second 12.05 V. Odier physical properties of thulium are given under Rare-Earth Elements and Metals. 

B. Evans, Assistant Chemist. Rare-Earth Information Center. Energy itnd Mineral Resources Research Institute. Iowa Slate University. Ames. I,A. http //www.cxternal.ameslab.gov/. Cerium Dysprosium Erbium Europium Gadolinium Holmium Lanthanum Lutetium Neodymium Rare-Earth Elements and Metals Praseodymium Samarium Scandium Terbium Thulium Ytterbium and Yttrium Daniel F. Farkas, Oregon State University. Corvallis. OR. http // oregonstate.edu/. Food Processing... 

The influence of steric factors was thoroughly studied in the reaction of Ln(btsa)3 with the alcohol tritox-H. While the reaction takes place with larger lanthanides like neodymium to yield the homoleptic alkoxide complexes (Eq. 18) [264], the analogous reaction does not work with smaller metals like yttrium and thulium (Eq. 19). However, variation of the reaction conditions to a stoichiometric solid reaction yielded a fully exchanged product along with an unexpected and unusual silylamine degradation [265] (Eq. 20). This degradation reaction seems to be sterically forced and points out N-Si bond disruptions and C-Si bond formations under mild conditions [114]. 

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