Symbol: Sc
Atomic Number: 21
Atomic Mass: 44.95591 amu (atomic mass units)
Melting Point: 1539.0 C (1812.15 K, 2802.2 F)
Boiling Point: 2832.0 C (3105.15 K, 5129.6 F)
Number of Protons: 21
Number of Electrons: 21
Number of Neutrons: 24
Classification: Transition Metal
Crystal Structure: Hexagonal
Density @ 293 K: 2.989 grams per cubic centimeter
Color: silver
The element scandium was predicted to exist by Dmitri Mendeleev, the scientist who put together the periodic table of elements. In 1871 no element with atomic number 21 had been found but he knew that one had to exist and he called it eka-boron as he reasoned that it should resemble boron in its chemical properties.
It was in 1876 that the Swedish chemist Lars Fredrik Nilson was trying to extract a pure sample of yttrium from the mineral ore euxenite when he found a new element within the ore. From ten kilograms of the ore Nilson managed to prepare two grams of scandium oxide. The pure metal was first produced in 1937 and the first full pound in weight of the element was purified in 1960. The element gets its name from the Latin for Scandinavia – “Scandia”.
The metal is soft and silvery white in color. When exposed to air the surface of the pure metal will develop a faint pinkish or yellowish hue. Scandium will react rapidly with many different acids. The element is more abundant in certain stars than it is on the planet earth.
There is one naturally occurring isotope of the element and that is scandium-45. This naturally occurring isotope is stable. About twenty five unstable isotopes of scandium have been recognized. The half lives of these unstable isotopes range from 318 milliseconds for scandium-45 to 83.79 days for scandium-46.
Scandium can be extracted from a number of mineral ores such as thortveitite and wiikite. Most of the world’s supply of the metal comes as a by-product from the processing of ores for uranium.
Scandium metal is a lightweight material and has been looked at for use in the aerospace industry but its comparative rarity and expense when compared to other similar metals means that it is unlikely to achieve widespread use.
Scandium has a few very specialized uses.
* Alloys of scandium have been used in the production of some sports equipment such as baseball bats and bicycle frames.
* An alloy of aluminum and scandium is being investigated as to its suitability for use in the production of fuel cells.
* Scandium oxide, a compound also known as scandia, is used to make high intensity light bulbs.
* Another compound, scandium iodide, is also important in lighting. A small amount of the compound when added to mercury vapor lamps will produce a light similar to natural sunlight. Such bulbs are used in the television and film industries.
