Erbium is one of the rare earth elements found in Row 6 of the periodic table. The elements in this family are also known as the lanthanides, after the first member of the family. Erbium's atomic number is 68, its atomic mass is 167.26, and its chemical symbol is Er.

Properties

Erbium is a typical metal with a bright, shiny surface. It is soft and malleable with a melting point of 2,772°F (1,522°C), a boiling point of about 4,500°F (about 2,500°C), and a density of 9.16 grams per cubic centimeter. Erbium tends to be moderately active, and does not react with oxygen as quickly as do most other lanthanides. Erbium compounds tend to be pink or red, making them useful for coloring glass and ceramics.

Occurrence and Extraction

The term rare earth elements is somewhat inappropriate as the elements in this family are not really very rare. The term actually refers to the difficulty in separating the elements from each other because of their chemical similarity. Erbium ranks about number 42 in abundance in the Earth's crust, making it more common than bromine, uranium, tin, silver, mercury, and other better-known elements. It is extracted from its ores by first being converted to erbium fluoride (EbF₃), which is then electrolyzed to obtain the pure metal: 2ErF₃ 2Er + 3F₂.

Discovery and Naming

Erbium was discovered in 1843 by the Swedish chemist Carl Gustav Mosander. Mosander spent many years analyzing an unusual new mineral that had been discovered in 1787 by the Swedish army office Carl Axel Arrhenius (1757-1824). That mineral, called yttria, was later to yield a total of nine new elements. Mosander suggested the name erbium for the element in honor of the town near which the mineral was discovered, Ytterby. Three other elements were also named after this small town: terbium, yttrium, and ytterbium.

Uses

The most important uses of erbium are in lasers and optical fibers. Erbium lasers are now being used to treat skin problems, such as removing wrinkles and scars. They work well for this purpose because the light they produce has relatively little energy and does not penetrate the skin very deeply. They also produce relatively little heat and cause few side effects. Erbium optical fibers are being used in long distance communication systems and in military applications. There are no commercially important erbium compounds.