Scandium, Sc, Atomic number 21

General

Scandium (by lat. Scandia "Skandinavien") is a chemical element with symbol Sc and atomic number 21. In the periodic table it is in the 3. Subgroup (group 3) or scandium. The soft, silver-white element is the first of the transition metals and rare metals is also attributed to earth.
Scandium was 1879 discovered by Lars Fredrik Nilson. From 10 kg euxenite gadolinite and he isolated an oxide with hitherto unknown properties. The presumed new element he named him in honor of his homeland "Scandium". Already 1869 said Dmitri Ivanovich Mendeleev, an element eka-boron with atomic number 21 ahead. It was only later, Per Teodor Cleve recognized the correspondence of scandium with the Eka-Bor.Reines scandium was first 1937 electrolytically from a eutectic melt of potassium, Lithium- and scandium in 700 to 800 ° C produced.
Scandium is one of the rare elements. Elementary, it does not happen, Only in some rare minerals you can find it in enriched form:

Thortveitit: (Sc,And)2Si2O7
Euxenit: (And,As,This,You,Th)(Nb,Take,You)2O6
Gadolinit Y2Fe2 Be2Si2O10
Ixiolit: (Take,Nb,Sn,Mn,Faith)4O8
Bazzit: (Sc,To the)2Be3Si6O18
Kolbeckit: ScPO4 · 2 H2O

Scandium is found in low concentrations in more than 800 Minerals. It is therefore also in the ore concentrates transition metals as a "contaminant" contained. These include Russian and Chinese wolframite- and Tantalitkonzentrate. Even in the treatment of uranium bearing ores fall in scandium.
The blue color of aquamarine, a variety of beryl, to be caused by Sc3 ions.

Extraction

The starting material is used mainly thortveitite, which is processed in several steps to scandium. A metallic scandium is then produced by reaction to fluoride and reduction with calcium.

Special features

Because of its density is one of the light metals, scandium. In air, it becomes dull, it forms a protective oxide layer yellowish. Scandium reacts with dilute acids to form hydrogen and trivalent cations. Made from water vapor 600 ° C the reaction to form scandium oxide Sc2O3. In aqueous solutions, Sc cations behave similarly to aluminum, which often presents difficulties for analytical separations. In a mixture of nitric acid and 48 % Hydrogen fluoride, it should be resistant.

Use

Its main use is as scandium scandium in high-pressure mercury vapor lamps, For example, the stadium lights. Together with holmium and dysprosium produces a light similar to daylight. Scandium is also used for the production of laser crystals. Magnetic data storage is added to increase the scandium Ummagnetisierungsgeschwindigkeit. Scandium as scandium chloride is used in micro quantities to be a very important component in the catalyst in the production of hydrochloric.
As an alloying addition of scandium shows structurally stabilizing and refining grain size effects. An aluminum-lithium alloy with low Scandiumzusatz used in the manufacture of some parts in Russian warplanes. Even in the modern bicycle industry (see race) Scandium is used. These alloys also contain relatively little scandium.
Scandium is combustible and therefore classified as flammable.

General
Name, Symbol

Atomic number

Scandium, Dc, 21
Series Transition metals
group, Period, Block 3, 4, d
Appearance silvery white
CAS-Nummer 7440-20-2
Mass fraction of element 5,1 ppm
Atomic
Atomic mass 44,955910 you
Atomradius 160 pm
Kovalenter Radius 170 pm
Elektronenkonf. [It] 3d(1) 4s2
1. Ionization 633,1 KJ / mol
2. Ionization 1235,0 KJ / mol
3. Ionization 2388,6 KJ / mol
Physically
Physical State fixed
Crystal structure hexagonal
Density 2,985 g/cm3
Magnetism paramagnetisch (χm = 2,6 * 10(-4))
Melting point 1814 K (1541 C)
Boiling point 3103 K (2830 C)
Molar Volume 15,00 * 10(-6)m(3)/mol
Heat of vaporization 318 KJ / mol
Schmelzwärme 16,0 KJ / mol
Electrical conductivity 1,81*10(6) A/(V * m)
Thermal conductivity 16 W /(m*K)
This entry was posted in Rare earth and tagged , , , , , , , , , . Bookmark the permalink.

Leave a Reply