|Name , symbol , atomic number||Dysprosium, Dy, 66|
|Group , period , block||La , 6 , f|
|Mass fraction of the earth's envelope||4.3 ppm|
|Atomic mass||162,500 (1) u|
|Atomic radius (calculated)||175 (228) pm|
|Covalent radius||192 pm|
|Electron configuration||[ Xe ] 4 f 10 6 s 2|
|1. Ionization energy||5.93905 (7) eV ≈ 573.03 kJ / mol|
|2. Ionization energy||11.647 (20) eV ≈ 1 123.8 kJ / mol|
|3. Ionization energy||22nd.89 (3) eV ≈ 2 210 kJ / mol|
|4. Ionization energy||41.23 (8) eV ≈ 3 980 kJ / mol|
|5. Ionization energy||62.1 (3) eV ≈ 5 990 kJ / mol|
|density||8.559 g / cm 3 (25 ° C )|
|magnetism||paramagnetic ( Χ m = 0.065)|
|Melting point||1680 K (1407 ° C)|
|boiling point||2873 K (2600 ° C)|
|Molar volume||19.01 · 10 −6 m 3 · mol −1|
|Heat of evaporation||280 kJ / mol|
|Heat of fusion||11.06 kJ mol −1|
|Speed of sound||2710 m s −1 at 293.15 K.|
|Electric conductivity||1.08 · 10 6 A · V −1 · m −1|
|Thermal conductivity||11 W m −1 K −1|
|Normal potential||−2.29 V (Dy 3+ + 3 e - → Dy)|
|Electronegativity||1.22 ( Pauling scale )|
|For other isotopes see list of isotopes|
As far as possible and customary, SI units are used.
Unless otherwise noted, the data given apply to standard conditions .
Dysprosium (from the Greek δυσπρόσιτος "inaccessible") is a chemical element with the element symbol Dy and the atomic number 66. In the periodic table it is in the group of lanthanoids and is therefore also one of the rare earth metals .
In 1886, the Frenchman Paul Émile Lecoq de Boisbaudran succeeded in isolating dysprosium (III) oxide from a sample of holmium oxide , which until then had been considered a single substance. Since the chemical properties of the lanthanides are very similar and they are always associated in nature, a distinction was only possible here with very complex analysis methods. Its share in the structure of the earth's crust is given as 0.00042 percent by weight. The starting minerals are monazite and bastnasite .
Extraction and presentation
After a laborious separation of the other dysprosium companions, the oxide is converted to dysprosium fluoride with hydrogen fluoride . This is then reduced to metallic dysprosium with calcium to form calcium fluoride . Remaining calcium residues and other impurities are separated off in an additional remelting process in a vacuum . High-purity dysprosium is obtained after distillation in a high vacuum.
Dysprosium is a silver-gray heavy metal that can be bent and stretched. Of the rare earth metal two modifications exist: At 1384 ° C, α-dysprosium (converts hexagonal most densely ) in β-dysprosium ( body-centered cubic ) in order.
The metal is very ignoble and therefore very reactive. In the air it becomes coated with an oxide layer, in water it is slowly attacked with formation of hydroxides, in dilute acids it is dissolved to form salts with formation of hydrogen.
The economic and technical importance of dysprosium are relatively minor. Its output is estimated to be less than 100 tons per year. It is used in various alloys, in special magnets and alloyed with lead as a shielding material in nuclear reactors. However, just the use in permanent magnets , as u. a. are used in the generators of some types of wind power plants, has made these rare earth metals a rare raw material.
- Together with vanadium and other elements, dysprosium is used to manufacture laser materials.
- Dysprosium is used for doping calcium fluoride and calcium sulfate crystals for dosimeters .
- Alloys containing terbium and dysprosium show strong magnetostriction and are used in materials testing technology.
- In neodymium-iron-boron magnets it increases the coercivity and extends the usable temperature range.
- Dysprosium oxide improves the dielectric behavior of barium titanate for capacitors .
- It is occasionally used for the production of control rods in nuclear technology because of its high capture cross-section for thermal neutrons .
- Dysprosium iodide improves the emission spectrum of metal halide lamps .
- Dysprosium cadmium - chalcogenides used as infrared source for studying chemical reactions.
- Dysprosium (III) sulfate Dy 2 (SO 4 ) 3 · 8 H 2 O pale yellowish green crystals.
- Harry H. Binder: Lexicon of the chemical elements. S. Hirzel Verlag, Stuttgart 1999, ISBN 3-7776-0736-3 .
- The values for the properties (info box) are taken from webelements.com (Dysprosium) , unless otherwise stated .
- CIAAW, Standard Atomic Weights Revised 2013 .
- Entry on dysprosium in Kramida, A., Ralchenko, Yu., Reader, J. and NIST ASD Team (2019): NIST Atomic Spectra Database (ver. 5.7.1) . Ed .: NIST , Gaithersburg, MD. doi : 10.18434 / T4W30F ( https://physics.nist.gov/asd ). Retrieved June 13, 2020.
- Entry on dysprosium at WebElements, https://www.webelements.com , accessed on June 13, 2020.
- NN Greenwood, A. Earnshaw: Chemistry of the elements. 1st edition. VCH, Weinheim 1988, ISBN 3-527-26169-9 , p. 1579.
- Robert C. Weast (Ed.): CRC Handbook of Chemistry and Physics . CRC (Chemical Rubber Publishing Company), Boca Raton 1990, ISBN 0-8493-0470-9 , pp. E-129 to E-145. Values there are based on g / mol and given in cgs units. The value specified here is the SI value calculated from it, without a unit of measure.
- Yiming Zhang, Julian RG Evans, Shoufeng Yang: Corrected Values for Boiling Points and Enthalpies of Vaporization of Elements in Handbooks. In: Journal of Chemical & Engineering Data . 56, 2011, pp. 328-337, doi: 10.1021 / je1011086 .
- Dysprosium. www.americanelements.com, accessed on March 27, 2016 (English).
- Holmium. www.americanelements.com, accessed on March 27, 2016 (English).
- Oliver Langenscheidt: Electrodes for HID lamps - diagnostics and simulation. Witten 2008. urn : nbn: de: hbz: 294-23610