Dysprosium, Two, 66

General

Dysprosium (of Greek. δυσπρόσιτος "inaccessible") is a chemical element with the element symbol Dy and atomic number 66. In the periodic table it is in the group of the lanthanides and the Frenchman is one da1886 PE. Lecoq de Boisbaudran the isolation of dysprosium from a sample of holmium, had to be held at this time for a single substance. Since the chemical properties of lanthanides are very similar and they occur in nature always associated, was also a distinction only with very sophisticated methods of analysis possible. Its share in the structure of the earth's crust with 0,00042 Weight percent indicated. The starting materials are monazite and bastnaesite.

Extraction

After an extensive separation of the other Dysprosiumbegleiter, the oxide with hydrogen fluoride to dysprosium fluoride reacted. Is then reduced with calcium to form calcium fluoride to the metallic dysprosium. Separation of remaining calcium residues and impurities occur in an additional remelting in vacuo. After a distillation under high vacuum to get to the high-purity dysprosium.

Special features

Dysprosium is a silvery-gray heavy metal, The bendable- and extensible. From the metal of the rare earths are two modifications: At 1384 ° C converts to α-dysprosium (hexagonal compaction test) in β-dysprosium (body-centered cubic) at. Das Metall ist sehr unedel und daher sehr reaktionsfähig. In the air it becomes covered with an oxide layer, in water it is slowly attacked by hydroxide, in dilute acids, it is dissolved hydrogen formation in salts.

Use

Economic and technical importance of dysprosium are relatively low. Thus, it has a capacity of less than 100 Estimated tons per year. It is used in various alloys, alloyed with lead in special magnet and a shielding material in nuclear reactors. However, just using the magnets for wind turbines has these rare earth metals made a rare commodity, also throttles the world's largest supplier of China's supply, to increase its own value.

Applications:

In combination with vanadium and other elements is dysprosium used for the production of laser materials.
Dysprosium is for doping calcium fluoride- and calcium sulphate crystals used for dosimeter.
Terbium- and dysprosiumhaltige alloys show a 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 capacitors for.
Mostly it is used because of its high thermal neutron Einfangquerschnittes for the manufacture of control rods in nuclear technology.
Dysprosium improves the emission spectrum of high-performance halogen lamps.
Dysprosium-cadmium chalcogenides are used as an infrared source for studying chemical reactions.

General
Name, Symbol, Number Dysprosium, Two, 66
Series Lanthanides
group, Period, Block The, 6, f
Appearance silvery white
CAS-Nummer 7429-91-6
Mass fraction of element 4,3 ppm
Atomic
Atomic mass 162, 50 you
Atomradius 175 (228) pm
Kovalenter Radius 192 pm
Elektronenkonf. [Car] 4f(10) 6s(2)
1. Ionization 573,0 KJ / mol
2. Ionization 1130 KJ / mol
3. Ionization 2200 KJ / mol
4. Ionization
Physically
Physical State fixed
Crystal structure hexagonal
Density 8,559 g/cm3 (25 ° C)
Mohs
Magnetism paramagnetisch (χm = 0,065)
Melting point 1680 K (1407 C)
Boiling point 2840 K (2567 C)
Molar Volume 19,01 * 10(-6)m(3)/mol
Heat of vaporization 230 KJ / mol
Schmelzwärme 11,06 KJ / mol
Speed ​​of sound 2710 m / s at 293,15 K
Electrical conductivity 1,08*10(6) A/(V * m)
Thermal conductivity 11 W /(m*K)
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