THULIUM Chemical Properties
- Melting point:
- 1545 °C(lit.)
- Boiling point:
- 1950 °C(lit.)
- 9.332 g/mL at 25 °C(lit.)
- Specific Gravity
- 90 μΩ-cm, 20°C
- Water Solubility
- slowly reacts with H2O; soluble in dilute acids [HAW93]
- Air & Moisture Sensitive
- CAS DataBase Reference
- 7440-30-4(CAS DataBase Reference)
- EPA Substance Registry System
- Thulium (7440-30-4)
THULIUM Usage And Synthesis
Thulium is a naturally occurring rare metal that exists is very small amounts mixed withother rare-earths. It is a bright silvery metal that is malleable and ductile and can be cuteasily with a knife. Its melting point is so high that it is difficult to force it into a meltedstate. Its vapor pressure is also high, and thus, much of the molten thulium evaporates intothe atmosphere. Its melting point is 1,545°C, its boiling point is 2,950°C, and its density is9.32g/cm3.
There are a total of 46 isotopes of thulium. One of these, Tm-169 is the onlystable isotope of thulium and accounts for the total atomic mass of the element. All theother isotopes are artificially produced and radioactive and have half-lives ranging from afew microseconds to two years.
Origin of Name
Named for Thule, the Greek word for Scandinavia, the most northerly habitable land in ancient mythology.
Thulium is the 61st most abundant element in the Earth’s crust and is found along withother rare-earths in monazite sand, which is about 50% rare-earths by weight. Only about0.007% of this is thulium. It is also found in bastnasite ore. It ranks 16th out of the 17 rareearthsin abundance. Thulium is usually found as an oxide along with other rare-earths. Likemost rare-earths, thulium can be separated from its ore by the ion-exchange process, whereits positive ion reacts with elements with negative ions like fluorine, chlorine, or oxygen toform binary compounds (e.g., Tm2O2). It can also be recovered as a by-product of the nuclearfission reaction in nuclear reactors.
Discovered in 1879 by Cleve. Thulium occurs in small quantities along with other rare earths in a number of minerals. It is obtained commercially from monazite, which contains about 0.007% of the element. Thulium is the least abundant of the rare-earth elements, but with new sources recently discovered, it is now considered to be about as rare as silver, gold, or cadmium. Ion-exchange and solvent extraction techniques have recently permitted much easier separation of the rare earths, with much lower costs. Only a few years ago, thulium metal was not obtainable at any cost; in 1996 the oxide cost $20/g. Thulium metal powder now costs $70/g (99.9%). Thulium can be isolated by reduction of the oxide with lanthanum metal or by calcium reduction of the anhydrous fluoride. The pure metal has a bright, silvery luster. It is reasonably stable in air, but the metal should be protected from moisture in a closed container. The element is silver-gray, soft, malleable, and ductile, and can be cut with a knife. Forty-one isotopes and isomers are known, with atomic masses ranging from 146 to 176. Natural thulium, which is 100% 169Tm, is stable. Because of the relatively high price of the metal, thulium has not yet found many practical applications. 169Tm bombarded in a nuclear reactor can be used as a radiation source in portable X-ray equipment. 171Tm is potentially useful as an energy source. Natural thulium also has possible use in ferrites (ceramic magnetic materials) used in microwave equipment. As with other lanthanides, thulium has a low-to-moderate acute toxicity rating. It should be handled with care.
Thulium is near the end of the lanthanide series, where the metals tend to be heavier thanthe ones located near the beginning of the series. It is so scarce that it requires the processing ofabout 500 tons of earth to extract four kilograms of thulium. The only element that is scarceris promethium, which is not found naturally on Earth.
Thulium is relatively scarce and expensive, which limits its commercial uses. Thulium-170,which is a radioactive isotope of thulium produced by fission in nuclear reactors, can be usedas small, portable X-ray sources. It also has limited use as an alloy metal with other metals andhas experimentally been used in lasers. (Note: Of all the isotopes of thulium, only thulium-169 is stable and nonradioactive.)
Thulium(III) carbonate hydrate has specialized uses in ceramics, glass, phosphors, lasers, and also is the important dopant for fibre amplifiers. Thulium(III) carbonate hydrate has use in ferrites, ceramic magnetic materials that are used in microwave equipment.
Ferrites, X-ray source.
Atomic number 69, group IIIB of the periodic table, a rare-earth element of the lanthanide groups, aw168.9342, valence of 3; no stable isotopes.
A soft malleable ductile silvery element of the lanthanoid series of metals. It occurs in association with other lanthanoids. Symbol: Tm; m.p. 1545°C; b.p. 1947°C; r.d. 9.321 (20°C); p.n. 69; r.a.m. 168.93421.
thulium: Symbol Tm. A soft greymetallic element belonging to thelanthanoids; a.n. 69; r.a.m. 168.934;r.d. 9.321 (20°C); m.p. 1545°C; b.p.1947°C. It occurs in apatite and xenotime.There is one natural isotope,thulium–169, and seventeen artificialisotopes have been produced. Thereare no uses for the element, whichwas discovered by Per Cleve (1840–1905) in 1879.
Fire risk in form of dust.
The dust and powder of thulium are explosive and toxic if inhaled or ingested. As with allradioactive elements, thulium can cause radiation poisoning.
- antimony, compound with thulium (1:1)
- ammonium thulium(3+) disulphate
- diammonium thulium pentanitrate
- thulium orthovanadate
- thulium vanadium oxide
- Thulium(III) sulfate, >=99.99%
- thulium hexaboride
- Thulium(III) nitrate trihydrate
- Thulium sulfate octahydrate
- THULIUM(III) ACETATE HYDRATE, 99.9%
- THULIUM ETHYL SULFATE
- THULIUM TELLURIDE
- THULIUM(III) OXIDE, 99.9%,THULIUM(III) OXIDE, 99.99%
- THULIUM(III) FLUORIDE, ANHYDROUS, 99.99%,thulium trifluoride
- thulium(3+) oxalate ,THULIUM(III) OXALATE, 99.99+%
- THULIUM SELENIDE
- THULIUM(III) CHLORIDE HEXAHYDRATE
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