Scandium

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Animated Scandium

History

From the Latin word Scandia, Scandinavia. On the basis of the Periodic System, Mendeleev predicted the existence of ekaboron, which would have an atomic weight between 40 of calcium and 48 of titanium. The element was discovered by Nilson in 1878 in the minerals euxenite and gadolinite, which had not yet been found anywhere except in Scandinavia. By processing 10 kg of euxenite and other residues of rare-earth minerals, Nilson was able to prepare about 2g of highly pure scandium oxide. Later scientists pointed out that Nilson's scandium was identical with Mendeleev's ekaboron.

Sources

Scandium is apparently much more abundant (the 23rd most) in the sun and certain stars than on earth (the 50th most abundant). It is widely distributed on earth, occurring in very minute quantities in over 800 mineral species. The blue color of beryl (aquamarine variety) is said to be due to scandium. It occurs as a principal component in the rare mineral thortveitite, found in Scandinavia and Malagasy. It is also found in the residues remaining after the extraction of tungsten from Zinnwald wolframite, and in wiikite and bazzite.

Most scandium is presently being recovered from thortveitite or is extracted as a by-product from uranium mill tailings. Metallic scandium was first prepared in 1937 by Fischer, Brunger, and Grienelaus who electrolyzed a eutectic melt of potassium, lithium, and scandium chlorides at 700 to 800°C. Tungsten wire and a pool of molten zinc served as the electrodes in a graphite crucible. Pure scandium is now produced by reducing scandium fluoride with calcium metal.

The production of the first pound of 99% pure scandium metal was announced in 1960.

Uses

About 20 kg of scandium (as Sc2O3) are used yearly in the U.S. to produce high-intensity lights. The radioactive isotope 46Sc is used as a tracing agent in refinery crackers for crude oil, etc.

Scandium iodide added to mercury vapor lamps produces a highly efficient light source resembling sunlight, which is important for indoor or night-time color TV.

General Info

AtomicNumber
21
Symbol
Sc
Name
Scandium

Atomic Info

Appearance
AtomicWeight
44.955912(6)
Color
E6E6E6
ElectronicConfiguration
[Ar] 3d1 4s2
ElectronegativityInPauling
1.36
AtomicRadiusInPM
144
IonRadiusInPM
74.5 (+3)
VanDerWaalsRadiusInPM
IEinKJmol
633
EAinKJmol
-18
OxidationStates
1, 2, 3
StandardState
solid
BondingType
metallic
MeltingPoint
1814
BoilingPoint
3103
Density
2.99
State
Transition metal
DiscoveredYear
1876