Neodymium, Nd, Atomic number 60

General

Neodymium (Nomenclature recommendation was temporarily: Neodymium) is a chemical element with the element symbol Nd and atomic number 60. In the periodic table it is in the group of lanthanides and is thus also one of the rare earth metals. The element name is derived from the Greek words neos νέος for "new" and δίδυμος didymos for "twin" (as a twin of lanthanum) from.

The metal is verwendet.Neodym especially for strong magnets, together with praseodymium 1885 durch Carl F. Auer von Welsbach isolated from the Carl Gustav Mosander discovered didymium. Purity metallic neodymium was only 1925 shown.

Neodymium occurs naturally only in chemical compounds associated with other lanthanides, preferably minerals, before:
Monazite (This, The, Th, Nd, And)PO4
Bastnäsit ((This,The,Th,Nd,And)(CO3)F)
Mixed metal contains up to 18 % Neodymium.
The main supplier of 97 % of world production, China. This leads to significant environmental problems there. “In the separation of neodymium from the sponsored rock produces toxic waste products, also uses radioactive uranium and thorium are released in the degradation process. These substances are at least partially into the ground water, thus contaminate flora and fauna and are significant for the people classified as harmful.” ARD television reported the magazine Panorama.

Other economically exploitable reserves are found in Australia.

Extraction

After extensive Neodymbegleiter removal of the oxide is converted to neodymium fluoride with hydrogen fluoride, followed by reduction with calcium to form calcium fluoride to neodymium. Calcium residues and impurities are separated in a remelting in a vacuum.
2011 researched the NDR, that in promoting, which is operated in especially China, generated by the released toxic waste and radioactive materials In addition to the enormous environmental damage.
The production by electrolysis of Neodymhalogeniden is rarely used today.

Neodym, Nd, Ordnungszahl 60Special features

The silvery-white lustrous metal is one of the rare earth metals and lanthanides. It is in the air a little more corrosion resistant than europium, Lanthanum, Cer oder Praseodym, is but slightly from a pink-violet oxide layer, which can flake off in air. At high temperatures, it burns to Nd2O3 sesquioxide.
It reacts with water to form hydrogen Neodymhydroxid for Nd(OH)3. With hydrogen it its hydride to NdH2. In addition to the main valence / oxidation 3 come under particular conditions, the oxide-
ationszahlen 2 and 4 before.

Use

Neodymium-iron-boron compounds for producing the strongest magnets. They are used for magnetic resonance imaging, Micro-motors and drives (Positioning the tape heads), Permanent magnet rotors (of. B. Step- and servo motors, efficient permanent magnet DC motors as. in some types of wind turbine, for driving electric- and hybrid vehicles as well as model drives), Linear motors for positioning, of. B. CNC machines, quality speakers and headphones. Compared to the samarium-cobalt magnets are stronger and much cheaper, but also much more sensitive to heat. Neodymium salts for dyeing enamel
Blue porcelain color
Neodymium(III)-oxide to the glass colouration. It produces very warm purple to maroon and gray tones. Such glasses have sharp absorption bands and are used in astronomy to calibrate.
Decolorization of ferrous glass
UV absorbing glasses (Sun protection glass)
Part of the industrially widely used neodymium-YAG laser
Neodymoxiddotiertes for barium titanate capacitor dielectrics
Due to its pyrophoric properties as alloying with cerium flint
For the preparation of neodymium catalyzed polybutadiene rubber (Nd-PBR)
Neodymium-iron-boron (Nd2Fe14B) is currently the strongest material for permanent magnets. You reach a remanence of up to 1,4 Tesla. The coercivity jHc varies in the range of 870 to 2750 kA / m.

General
Name, Symbol, Number Neodymium, Nd, 60
Series Lanthanides
group, Period, Block The, 6, f
Appearance silvery white, yellowish
CAS-Nummer 7440-00-8
Mass fraction of element 22 ppm
Atomic
Atomic mass 144,24 you
Atomradius 185 pm
Kovalenter Radius 201 pm
Elektronenkonf. [Car] 4f(4) 6s2
1. Ionization 533,1 KJ / mol
2. Ionization 1040 KJ / mol
3. Ionization 2130 KJ / mol
Physically
Physical State fixed
Crystal structure hexagonal
Density 7,003 g/cm3 (25 ° C)
Magnetism paramagnetisch (χm = 3,6 * 10(-3))
Melting point 1297 K (1024 C)
Boiling point 3373 K (3100 C)
Molar Volume 20,59 * 10(-6)m(3)/mol
Heat of vaporization 285 KJ / mol
Schmelzwärme 7,1 KJ / mol
Electrical conductivity 1,56*10(6) A/(V * m)
Thermal conductivity 17 W /(m*K)
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