Erbium, He, Atomic number 68

General

Erbium is a chemical element with atomic symbol He and atomic number 68. In the periodic table it is in the group of lanthanides and is thus also one of the rare earth metals. The name derives from the pit from Ytterby near Stockholm, as well as of ytterbium, Terbium Yttrium und. Erbium (after Ytterby, a Swedish mine) was 1843 discovered by Carl Gustav Mosander. However, these were in the supposedly pure oxide is a mixture of the oxides of erbium, Scandium, Holmium, Thulium and ytterbium.

Made to the later Enlightenment, the chemist Marc Delafontaine and Berlin deserve. Pure erbium presented 1905 the French chemist Georges Urbain and the American chemist Charles James ago.

Erbium is a rare metal (3,8 ppm).

Extraction

After an extensive separation of the other Erbiumbegleiter, the oxide with hydrogen fluoride to Erbiumfluorid reacted. Is then reduced with calcium to form calcium fluoride to the metallic erbium. Separation of remaining calcium residues and impurities occur in an additional remelting in vacuo.

Special features

The silver-white lustrous rare earth metal is malleable, but also quite brittle. In air erbium runs on gray, But it is quite resistant. At higher temperatures, it burns Er2O3 the sesquioxide. With water it reacts with evolution of hydrogen to hydroxide. In mineral acids it dissolves with the formation of hydrogen on.

In its compounds it is the oxidation state +3 before, the Er3 ions in water to form pink colored solutions. Solid salts are also colored pink.

Use

Erbium-doped optical fiber amplifiers are used for optical, which are capable of, to amplify a light signal, without it previously into an electrical signal transform. Gold is worth as a host material with a few hundred ppm of Er magnetic calorimeter used as a sensor material for high-resolution particle detection in physics and engineering.

Erbium is used along with other rare-earth elements such as neodymium or holmium laser doping of the crystals in solid-state lasers (He:YAG-Laser, see also Nd:YAG-Laser). The He:YAG laser is mainly used in human medicine. He has a wavelength of 2940 nm and thus an extremely high absorption in tissue water of about. 12000 pro cm. It comes to the sudden evaporation and thus to the photoablation of tissue in thin layers. It is suitable for the removal of a variety of benign skin lesions. A biopsy is required before, to exclude malignancy. Melanomas are ablated, for example, strongly suspected, to form by during ablation detached cells via the bloodstream metastases.

He also is in the processing of hard tissue such as bone, Tooth enamel and dentin (healthy and carious) used. Another erbiumbasierter laser is the He,Cr:YSGG-Laser, of a slightly lower wavelength of 2790 nm, But the same medical or. dental indications served.

General
Name, Symbol, Number Erbium, He, 68
Series Lanthanides
group, Period, Block The, 6, f
Appearance silvery white
CAS-Nummer 7440-52-0
Mass fraction of element 2,3 ppm
Atomic
Atomic mass 167,26 you
Atomradius 175 pm
Kovalenter Radius 189 pm
Elektronenkonf. [Car] 4f(12) 6s2
1. Ionization 589,3 KJ / mol
2. Ionization 1150 KJ / mol
3. Ionization 2194 KJ / mol
4. Ionization
Physically
Physical State fixed
Crystal structure hexagonal
Density 9,045 g/cm3 (25 ° C)
Magnetism paramagnetisch (χm = 1,4 · 10−3)
Melting point 1802 K (1529 C)
Boiling point 3141 K (2868 C)
Molar Volume 18,46 * 10(-6)m(3)/mol
Heat of vaporization 285 KJ / mol
Schmelzwärme 19,9 KJ / mol
Electrical conductivity 1,16*10(6) A/(V * m)
Thermal conductivity 15 W /(m*K)
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