Thulium ( Latin Thulium ) is a chemical element of the thirteenth group [3] of the sixth period of the periodic system of chemical elements . It is designated by the symbol Tm , atomic number - 69, refers to the group of lanthanides . The simple substance thulium is an easily processed silver-white metal .
| Thulium | ||||
|---|---|---|---|---|
| β Erbium | Ytterbium β | ||||
| ||||
| The appearance of a simple substance | ||||
| Soft silver white metal | ||||
 | ||||
| Atom properties | ||||
| Name, symbol, number | Thulium / Thulium (Tm), 69 | |||
| Atomic mass ( molar mass ) | 168.93421 (2) [1] a. E. m. ( g / mol ) | |||
| Electronic configuration | [Xe] 4f 13 6s 2 | |||
| Atom radius | 177 pm | |||
| Chemical properties | ||||
| Covalent radius | 156 pm | |||
| Ion radius | (+ 3e) 87 pm | |||
| Electronegativity | 1.25 (Pauling scale) | |||
| Electrode potential | Tm β Tm 3+ -2.32 V Tm β Tm 2+ -2.3 V | |||
| Oxidation state | 3, 2 | |||
| Ionization energy (first electron) | 589.0 (6.10) kJ / mol ( eV ) | |||
| Thermodynamic properties of a simple substance | ||||
| Density (at N. at. ) | 9.321 g / cmΒ³ | |||
| Melting temperature | 1818 K | |||
| Boiling temperature | 2220 K | |||
| Beats heat of vaporization | 232 kJ / mol | |||
| Molar heat capacity | 27.0 [2] J / (K Β· mol) | |||
| Molar volume | 18.1 cmΒ³ / mol | |||
| The crystal lattice of a simple substance | ||||
| Lattice structure | hexagonal | |||
| Lattice options | a = 3,540 c = 5.56 Γ | |||
| C / a ratio | 1,570 | |||
| Other characteristics | ||||
| Thermal conductivity | (300 K) (16.9) W / (mK) | |||
| CAS Number | 7440-30-4 | |||
| 69 | Thulium |
Tm | |
| 4f 13 6s 2 | |
Content
History
Thulium was discovered by the Swedish chemist P.T. Kleve in 1879 when searching for impurities to erbium oxide Er 2 O 3 . The same method previously allowed K. G. Mosander to discover other rare earth elements . With the release of impurities, Cleve obtained two oxides β brown holmium oxide and green thulium oxide. In 1911, T.W. Richards received the element in its purest form and measured its atomic weight.
Name Origin
Having isolated oxide of an unknown element, the Swedish chemist Per Theodor Kleve gave it the name Thulium in honor of the legendary island of Thule located in northern Europe ( dr. Greek ΞΞΏΟλη , lat. Thule ).
Getting
Metallic thulium is obtained by metallothermal reduction of thulium trifluoride using metallic calcium :
Properties
Solutions of thulium salts are colored green [4] .
Prevalence in nature
Thulium is a rare element, its content in the earth's crust is 2.7β 10 β5 mass. %, in sea water - 10 β7 mg / liter [2] . Along with other rare earth elements, thulium is present in minerals such as xenotime , euxenite , monazite , loparite and some others.
Isotopes
The thulium-170 isotope is used for the manufacture of portable x-ray medical devices, as well as in metal defectoscopy. More recently, it has been proposed as a fuel in radioisotope energy sources .
Application
Magnetic storage media
Production of ferro-pomegranates for the production of DTMs (information carriers).
Laser materials
Thulium ions are used to generate infrared radiation with a wavelength of 1.91 microns . In addition, thulium metal pairs are used to excite laser radiation with a tunable wavelength (frequency).
Thermoelectric materials
Thulium monotelluride has a very high thermoelectric power (700 ΞΌV / K), and the efficiency of thermoelectric converters made on its basis is very high (with a decrease in the price of thulium, its use in the production of thermoelements will increase sharply). In addition, thulium telluride is used to regulate the semiconductor properties of lead telluride (modifier).
Nuclear Power
Thulium borate is used in atomic technology (special enamels).
Biological role
Thulium does not play any biological role, although it is known that it stimulates the metabolism [5] . Soluble thulium salts are low toxic, but insoluble compounds are non-toxic. The element is practically not absorbed by plants and, therefore, cannot get into the food chain [5] . The average content of thulium in plants is about 1 mg per tonne of dry weight [5] .
Prices
The price of thulium metal with a purity of> 99.9% is approximately 2.2 thousand dollars per 1 kg, the price of thulium oxide with a purity of 99.9% is 1.1 thousand dollars per 1 kg [6] .
Notes
- β Michael E. Wieser, Norman Holden, Tyler B. Coplen, John K. BΓΆhlke, Michael Berglund, Willi A. Brand, Paul De BiΓ¨vre, Manfred GrΓΆning, Robert D. Loss, Juris Meija, Takafumi Hirata, Thomas Prohaska, Ronny Schoenberg , Glenda O'Connor, Thomas Walczyk, Shige Yoneda, Xiang β Kun Zhu. Atomic weights of the elements 2011 (IUPAC Technical Report ) // Pure and Applied Chemistry . - 2013 .-- Vol. 85 , no. 5 . - P. 1047-1078 . - DOI : 10.1351 / PAC-REP-13-03-02 .
- β 1 2 Chemical Encyclopedia: in 5 vols. / Editorial: Zefirov N.S. (Ch. Ed.). - M .: Big Russian Encyclopedia, 1999. - V. 5. - P. 16.
- β In the outdated βshortβ form of the periodic table, it is a side subgroup of the third group.
- β Remy, 1966 , p. 535.
- β 1 2 3 John Emsley. Nature's building blocks: an AZ guide to the elements . - US: Oxford University Press, 2001. - P. 442β443. - ISBN 0-19-850341-5 .
- β Prices of thulium and its compounds
Links
Literature
- Remy G. Inorganic chemistry course. - M .: Mir, 1966. - T. 2. - 838 p.