Thulium isotope

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). 

Tin hold the record with 10 stable isotopes. There are 19 so-called "pure elements" of which there is only one isotope. These anisotopic elements are beryllium, fluorine, sodium, aluminum, phosphorus, scandium, manganese, cobalt, arsenic, yttrium, niobium, rhodium, iodine, cesium, praseodymium, terbium, holmium, thulium, gold, and bismuth. 

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. 

Phosphorus is an unusual element, because it has only one single isotope, phosphorus-31, and that this isotope is NMR-active with a spin of xh. The only other elements for which this is the case are fluorine, yttrium, rhodium and thulium. 

ISOTOPES There are a total of 46 isotopes of thulium. One of these, Tm-169 is the only stable isotope of thulium and accounts for the total atomic mass of the element. All the other isotopes are artificially produced and radioactive and have half-lives ranging from a few microseconds to two years. 

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.)... 

Moseley s work not only shed much fight on the periodic system and the relationships between known elements and the radioactive isotopes, but was also a great stimulus in the search for the few elements remaining undiscovered (11). One of the first chemists to utilize the new method was Professor Georges Urbain of Paris, who took his rare earth preparations to Oxford for examination. Moseley showed him the characteristic fines of erbium, thulium, ytterbium, and lutetium, and confirmed in a few days the conclusions which Professor Urbain had made after twenty years... 

Only one naturally occurring isotope of thulium exists thulium-169. Isotopes are two or more forms of an element. Isotopes differ from each other according to their mass number. The number written to the right of the element s name is the mass number. The mass number represents the number of protons plus neutrons in the nucleus of an atom of the element. The number of protons determines the element, but the number of neutrons in the atom of any one element can vary. Each variation is an isotope. 

Forty-six radioactive isotopes of thulium are known also. A radioactive isotope is one that breaks apart and gives off some form of radiation. Radioactive isotopes are produced when very small particles are fired at atoms. These particles stick in the atoms and make them radioactive. 

Thulium-170, a radioactive isotope of thulium, has been used in portable X-ray machines for use in medical and dental procedures. This isotope gives off gamma radiation. Gamma radiation is very similar to X rays. They pass through soft tissues in the body like X rays. But they are blocked by bones and other thick materials. So a small amount of thulium-170 acts just like a tiny X-ray machine. It can be carried around more easily than can a big X-ray machine. Another radioactive isotope of thulium, thulium-171, may have some application as an energy source. 

The nature of the thermal decomposition of thalium peroxides has been investigated. A similar study of thulium and ytterbium nitrate tetrahydrates produced no evidence for the formation of anhydrous nitrates. The new Tm isotope was found to have a half life of 3.6 0.3 min. 

The most common isotope of thulium is Tm, which has a natural abundance of 100 percent and is the only stable isotope. Other isotopes range from Tm to Tm and have half-lives ranging from 0.36 milliseconds ( Tm) to 1.92 years ( Tm). Examples of thuhum compounds include thulium iodide (Tmlj), thulium fluoride (TmFj), and thulium oxide (Tm203). 

Thulium, Tm at. wt 168.9342 at. no. 69 valence 3- A rare earth element of the yttrium group. One naturally occurring isotope ltsTm artificial, radioactive isotopes ... 

Naturally occurring Thulium has one stable isotope Tm with an atomic mass of 168.934211 (u). For thulium, 34 radioisotopes have been identified. Of these the most stable are Tm with a half-life of 1.92 years, °Tm with a half-life of 128.6 days, Tm with a half-life of 93.1 days, and Tm with a half-life of 9.25 days. All the other radioactive isotopes have half-lives that are less than 64 h, and most of them have half-lives that are less than 2 min. 

Thulium is a silver-gray, ductile metal, unreactive in air if protected from moisture. Thulium has almost no practical applications. The y-radiation from the radioactive isotope °Tm has, however, been examined for use in materials testing and as a... 

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