Atomic Number: 21
Atomic Symbol: Sc
Atomic Weight: 44.955912
Melting Point: 2,806 F (1,541 C)
Boiling Point: 5,137 F (2,836 C)
Word origin: The word scandium comes from the Latin word for Scandinavia: Scandia.
Discovery: Scandium was discovered by Lars Fredrik Nilson in 1878. He found it in the minerals euxenite and gadolinite, which at the time had not been found anywhere except Scandinavia. Previously, Dmitri Mendeleev had theorized about an undiscovered element that he called ekaboron. Upon Nilson’s discovery, scientists acknowledged that scandium matched Mendeleev’s description of ekaboron.
Properties of scandium
Scandium is a silver-white metal that develops a slightly yellow or pinkish cast when exposed to air. It is one of the transition metals, readily forming a white coating nitride in air, reacting with water and burning with a yellow-red flame. [See Periodic Table of the Elements]
It is a relatively soft element, resembling yttrium and other rare earth metals more than common ones like aluminum or titanium. Scandium is very light and has a much higher melting point than aluminum, making it of interest to spacecraft designers. It is not attacked by the 1:1 mixture of nitric acid (HNO3) and 48 percent hydrogen fluoride (HF).
Scandium has a radioactive isotope 46Sc.
Sources of scandium
Scandium is the 23rd most abundant element in the sun and certain stars, yet it is the 50th most abundant element on Earth. It is, nevertheless, widely distributed on our planet, existing in very minute quantities in more than 800 types of minerals. The blue color of beryl's aquamarine variety is thought to be caused by scandium.
A high concentration of scandium is found in the rare Scandinavian and Malagasy mineral thortveitite, of which it is a principal component. Scandium is also found in residues that remain after the extraction of tungsten from Zinnwald wolframite, wiikite and bazzite.
Pure scandium is produced by reducing scandium fluoride with calcium metal.
Today, most scandium is recovered from thortveitite or it is extracted as a byproduct of uranium mill tailings.
Uses of scandium
Scandium is used primarily as a light source. About 20 kilograms of scandium are used yearly in the United States to produce high-intensity lights. Scandium’s radioactive isotope is used as a tracing agent in refinery crackers for crude oil and other materials. When scandium iodide is added to mercury vapor lamps, it produces a highly efficient light source that resembles sunlight. This is used for indoor and nighttime color television.
(Source: Los Alamos National Laboratory)