What are the different uses of scandium



properties
Generally
Name, symbol, atomic number Scandium, Sc, 21
seriesTransition metals
Group, period, block3, 4, d
Look silvery white
Mass fraction of the earth's envelope 5 · 10-4 %
Atomic
Atomic mass 44.955910 u
Atomic radius (calculated) 160 (184) pm
Covalent radius 144 pm
Van der Waals radius - pm
Electron configuration [Ar] 3d1 4s2
Electrons per energy level 2, 8, 9, 2
Work function 3.50 eV
1. Ionization energy 633.1 kJ / mol
2. Ionization energy 1235.0 kJ / mol
3. Ionization energy 2388.6 kJ / mol
Physically
Physical state firmly
Modifications -
Crystal structure hexagonal
density 2.985 g / cm3
Mohs hardness 2,5
magnetism -
Melting point 1814 K (1541 ° C)
boiling point 3103 K (2830 ° C)
Molar volume 15,00 · 10-6 m3/ mol
Heat of evaporation 314.2 kJ / mol
Heat of fusion 14.1 kJ / mol
Vapor pressure

22.1 Pa at 1812 K.

Speed ​​of sound m / s
Specific heat capacity 568 J / (kg K)
Electric conductivity 1,77 · 106S / m
Thermal conductivity 15.8 W / (m K)
Chemically
Oxidation states 3
Oxides (basicity) Sc2O3 (weakly basic)
Normal potential -2.077 V (Sc3+ + 3e- → Sc)
Electronegativity 1.36 (Pauling scale)
Isotopes
isotopeNHt1/2ZMZE MeVZP
43Sc

{syn.}

3.891 hε2,22143Approx
44Sc

{syn.}

3.927 hε3,65344Approx
45Sc

100 %

Stable
46Sc

{syn.}

83.79 dβ-2,36746Ti
47Sc

{syn.}

3.3492 dβ-0,60047Ti
48Sc

{syn.}

43.67 hβ-3,99448Ti
49Sc

{syn.}

57.2 minβ-2,00649Ti
NMR properties
  Spinγ in
rad · T−1· S−1
E. fL. at
W = 4.7 T
in MHz
45Sc 7/2 6,499 · 107 0,301 46,6
safety instructions
Hazardous substance labeling
Scandium powder

R and S phrases R: 11 (powder)[1]
S: 16 (powder)[1]
As far as possible and customary, SI units are used.
Unless otherwise noted, the data given apply to standard conditions.


Scandium (from lat. Scandia "Scandinavia") is a chemical element in the periodic table of the elements with the symbol Sc and the atomic number 21. The soft, silver-white element is the first of the transition metals and is also assigned to the rare earth metals.

history

Scandium was discovered by Lars Fredrik Nilson in 1879. From 10 kg of euxenite and gadolinite, he isolated an oxide with previously unknown properties. He named the new element he suspected "Scandium" in honor of his homeland. As early as 1869, Dmitri Ivanovich Mendeleev predicted an element Eka-Bor with the ordinal number 21. Only Per Teodor Cleve later recognized the correspondence of the scandium with the eka-boron.

Pure scandium was first produced electrolytically in 1937 from a eutectic melt of potassium, lithium and scandium chloride at 700 to 800 ° C.

Occurrence

Scandium is one of the rare elements. It does not occur elementally, it is only found in a few rare minerals in enriched form:

  • Thortveitite: (Sc, Y)2Si2O7
  • Euxenite
  • Gadolinite
  • Scandium ixiolite: (Ta, Nb, Sn, Mn, Fe, Sc)2O4
  • Bazzit: (Sc, Fe)2Be3Si6O18
  • Kolbekit: ScPO4 · H2O

Scandium is found in low concentrations in over 800 minerals. It is therefore also contained in ore concentrates of the transition metals as an "impurity". These include Russian and Chinese wolframite and tantalite concentrates. Scandium compounds are also produced when processing ores containing uranium.
The blue color of aquamarine, a variety of beryl, is said to be due to Sc3+ Ions are caused.

Extraction and manufacture

The main starting material is thortveitite, which is processed into scandium oxide in several process steps. Metallic scandium is then produced by converting it to fluoride and reducing it with calcium.

properties

Because of its density, scandium is one of the light metals. In air it becomes dull, a protective yellowish oxide layer is formed. Scandium reacts with dilute acids to form hydrogen and trivalent cations. The conversion to scandium oxide Sc takes place in steam from 600 ° C2O3. In aqueous solutions, Sc cations behave similarly to aluminum, which often causes difficulties in analytical separations. In a mixture of nitric acid and 48% hydrogen fluoride, it should be resistant.

use

Scandium is mainly used as scandium iodide in high-performance, high-pressure mercury vapor lamps, for example for stadium lighting. Together with holmium and dysprosium, a light similar to daylight is created. Scandium is also used to make laser crystals.
Scandium oxide is added to magnetic data storage media to increase the rate of magnetization reversal.
As an alloy additive, scandium shows structure-stabilizing and grain-size-reducing effects. An aluminum-lithium alloy with a small amount of scandium is used to manufacture some components in Russian fighter planes. Scandium alloys, which are often lighter than carbon components, are also used in the modern bicycle industry.

safety instructions

Scandium powder is flammable and therefore classified as flammable.

links

swell

  1. ab Safety data sheet (Acros)