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Scandium - Sc

Chemical properties of scandium - Health effects of scandium - Environmental effects of scandium

Atomic number

21

Atomic mass

44.9559 g.mol -1

Electronegativity according to Pauling

unknown

Density

3.0 g.cm-3 at 20°C

Melting point

1541 °C

Boiling point

2836 °C

Vanderwaals radius

0.161 nm

Ionic radius

0.083 nm (+3)

Isotopes

7

Electronic shell

[ Ar ] 3d1 4s2

Energy of first ionisation

640.5 kJ.mol -1

Energy of second ionisation

1233 kJ.mol -1

Energy of third ionistion

2389 kJ.mol -1

Energy of fourth ionisation

7089 kJ.mol -1

Discovered by

Lars Nilson in 1879

Scandium - Sc

Scandium

Scandium is a soft, silvery transition element which occurs in rare minerals from Scandinavia. It develops a slightly yellowish or pinkish cast when exposed to air. Scandium tarnished in air and burn easily, once it has been ignited. It reacts with water to form hydrogen gas and will dissolve in many acids. Pure scandium is produced by heating scandium fluoride (ScF3) with calcium metal.

Applications

Scandium is one of the rare chemicals, that can be found in houses in equipment such as colour televisions, fluorescent lamps, energy-saving lamps and glasses. The use of scandium is still growing, due to the fact that it is suited to produce catalysers and to polish glass.
The main application by volume is in aluminium-scandium alloys for the aerospace industry and for sports equipment (bikes, baseball bats, etc.) which rely on high performance materials. It has been shown to reduce solidification cracking during the welding of high strength aluminium alloys.

Scandium in the environment

Scandium can rarely be found in nature, as it occurs in very small amounts. Scandium is usually found only in two different kinds of ores. Thortveitite is the primary source of scandium with uranium mill tailings by-products also being an important source. World production amount to only 50 kg per year. There is no estimate of how much is potentially available.
Scandium is only the 50th most abundant element on hearth, it is distributed widely, occurring in trace quantities in over 800 minerals. The blue color of the aquamarine variety of beryl is thought to be caused by scandium.
Only about 3% of plants that were analysed for scandium shows its presence, and even those amounts were tiny, with vegetable having only 5 ppb although grass has 70 ppb.

Health effects of scandium

Scandium has no biological role. Only trace amounts reach the food chain, so the average person's daily intake is less than 0.1 microgram.

Scadium is not toxic, although there have been suggestions that some of its compounds might be cancerogenic.

Scandium is mostly dangerous in the working environment, due to the fact that damps and gasses can be inhaled with air. This can cause lung embolisms, especially during long-term exposure. Scandium can be a threat to the liver when it accumulates in the human body.


Effects of scandium on the environment

Scandium is dumped in the environment in many different places, mainly by petrol-producing industries. It can also enter the environment when household equipment is thrown away. Scandium will gradually accumulate in soils and water soils and this will eventually lead to increasing concentrations in humans, animals and soil particles.
With water animals scandium causes damage to cell membranes, which has several negative influences on reproduction and on the functions of the nervous system.

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