7440-30-4 Usage
Description
Thulium is a naturally occurring rare metal that is part of the lanthanoid series of metals. It is the 61st most abundant element in the Earth's crust and is found along with other rare-earth elements in monazite sand and bastnasite ore. Thulium is a bright silvery metal that is malleable, ductile, and can be cut easily with a knife. It has a high melting point of 1,545°C and a boiling point of 2,950°C, with a density of 9.32g/cm3. Thulium has one natural, stable, and nonradioactive isotope, thulium-169, and several artificial isotopes. Thulium is relatively scarce and expensive, which limits its commercial uses.
Uses
1. Used in Medical Applications:
Thulium is used as a portable X-ray source for medical and dental diagnosis, as well as for detecting defects in mechanical and electronic inaccessible components. These sources do not require excessive protection and typically have a small cap of lead.
2. Used in Alloys:
Thulium is used as an alloy metal with other metals, enhancing their properties and contributing to the creation of superalloys.
3. Used in Ferrite Applications:
Thulium is used as a dopant in ferrites, which are ceramic magnetic materials used in microwave equipment.
4. Used in Lasers:
Thulium has experimentally been used in lasers, taking advantage of its unique properties to improve their performance.
5. Used in Crystal Applications:
Thulium products are mainly used in making crystals and lasers, benefiting from its distinctive characteristics.
6. Used in Arc Lighting:
Thulium is used in arc lighting for its unusual spectrum, providing unique lighting properties.
7. Used in Ceramics, Glass, and Phosphors:
Thulium(III) carbonate hydrate has specialized uses in ceramics, glass, and phosphors, contributing to their enhanced properties.
8. Used in Fiber Amplifiers:
Thulium(III) carbonate hydrate is an important dopant for fiber amplifiers, improving their performance and efficiency.
Isotopes
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.
History
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.
Characteristics
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.
Production Methods
Thulium is recovered from xenotime, gadolinite, euxenite, samarskite, and other minerals. The first step of recovery involves opening the ores. If xenotime, (Y)PO4 is the starting material, the mineral is heated with an excess of sulfuric acid (95%). The product mixture is treated with cold water to separate water-soluble sulfates from unreacted mineral, silica, and other insoluble residues. The solution is filtered and yttrium and the individual rare earths are separated from this solution by ion exchange. The tripositive lanthanide metal ions and yttrium are absorbed on an appropriate cation exchange column and eluted with ammonium ethylenediamine tetraacetic acid (EDTA) at pH 8.4. The cation-exchange resin is pretreated with an equimolar mixture (1 M) of copper sulfate-sulfuric acid. The various eluate fractions are collected, and are treated with oxalic acid. The metals are precipitated as oxalates. Precipitate from the thulium fraction is calcined at 800°C to convert oxalate into oxide, Tm2O3. If thulium is to be recovered from gadolinite, Be2Fe(Y)2Si2O10, pulverized mineral is opened by digesting with hot nitric acid-hydrochloric acid mixture. Insoluble silica residues are removed by filtration. The solution now contains beryllium, iron, yttrium, and the rare earths. The solution is treated with oxalic acid to precipitate yttrium and the rare earths. The precipitate is calcined at 800°C to form rare earth oxides. The oxide mixture is dissolved in an acid from which yttrium and the rare earths are separated by the ionexchange as above. Caustic fusion may be carried out instead of acid digestion to open the ore. Under this condition silica converts to sodium silicate and is leached with water. The insoluble residue containing rare earths and yttrium is dissolved in an acid. The acid solution is fed to an ion exchange system for separating thulium from other rare earths,Thulium metal is prepared from its oxide by reduction with lanthanum at its melting point of 1,545°C. Thulium is separated from lanthanum by sublimation in vacuum. The metal vapor is condensed into crystalline metal in purified form free from lanthanum.
Hazard
Fire risk in form of dust.
Hazard
The dust and powder of thulium are explosive and toxic if inhaled or ingested. As with allradioactive elements, thulium can cause radiation poisoning.
Check Digit Verification of cas no
The CAS Registry Mumber 7440-30-4 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 7,4,4 and 0 respectively; the second part has 2 digits, 3 and 0 respectively.
Calculate Digit Verification of CAS Registry Number 7440-30:
(6*7)+(5*4)+(4*4)+(3*0)+(2*3)+(1*0)=84
84 % 10 = 4
So 7440-30-4 is a valid CAS Registry Number.
InChI:InChI=1/Tm
7440-30-4Relevant articles and documents
Liquid-liquid solvent extraction of rare earths from chloride medium with sec-nonylphenoxy acetic acid and its mixtures with neutral organophosphorus extractants
Xiao, Pengfei,Bao, Changli,Song, Naizhong,Li, Cui,Jia, Qiong
, p. 1157 - 1161 (2011/10/18)
In the present study, sec-nonylphenoxy acetic acid (CA100) and its mixtures with four neutral organophosphorus extractants, tri-butyl-phosphate (TBP), 2-ethylhexyl phosphonic acid di-2-ethyl ester (DEHEHP), Cyanex923, and Cyanex925 have been applied to the extraction of rare earths. Results show that all the four mixing systems do not have evident synergistic effects on the extraction of rare earths. The different extraction effects have been considered to the separation of rare earths. The four mixtures may be applied to the separation of yttrium from some certain lanthanoids at proper mole fractions of CA100. Pleiades Publishing, Ltd., 2011.
Temperature dependent rate constants for the reactions of gas phase lanthanides with N2O
Campbell, Mark L.
, p. 562 - 566 (2007/10/03)
The reactivity of gas phase lanthanide (Ln) atoms (Ln=La-Yb with the exception of Pm) with N2O from 298 to 623 K is reported. Lanthanide atoms were produced by the photodissociation of Ln(TMHD)3 (TMHD=2,2,6,6-tetramethyl-3,5-heptanat
Thermodynamics of sublimation and crystal chemistry of Tm0.77Te
Petzel, T.,Ludwigs, J.,Greis, O.
, p. 317 - 328 (2008/10/08)
The congruent vaporization of solid Tm0.77Te (rhombohedral, with hexagonal lattice parameters a = 430.9 pm, c = 1083.8 pm) was investigated by the Knudsen effusion weight-loss technique over the temperature range 1624 - 1798 K. Using literature data for the enthalpies of dissociation of gaseous TmTe and Te2 and for the free energy functions of gaseous TmTe, Te2, thulium and tellurium, an equation for vaporization to the atoms is given. A vapor pressure equation is provided. Second and third law calculations based on estimated thermodynamic data for Tm0.77Te yielded the standard enthalpies and entropies of reaction. The crystal chemistry and thermochemical properties are discussed.
