Rare Earths -- The Fraternal Fifteen
What are rare earths? To see and read an elementary primer, check Rare Earths – The Fraternal Fifteen. The 46-page pamphlet describes this family of chemical elements that have similar chemical properties and different physical behaviors, especially the magnetic and optical properties.
"Rare earths impact all of us," Karl A. Gschneidner, Jr., explains. "When you watch TV or use a color monitor, the red and green colors are due to two of the rare earths. Also, your automobile contains lots of products made from the rare earths: the onboard computer, the electric motors, loud speakers, sensors, and a three-way exhaust catalyst to remove pollutants from the combustion products of the gasoline or diesel engine."
Dr. Gschneidner wrote this pamphlet in 1964 as part of the U.S. Atomic Energy’s “Understanding the Atom” series. Now he's the Chief Scientist of the Critical Materials Institute. After a brief introduction, the pamphlet includes the history, the atomic structure and the chemistry of rare earths, which includes how they are separated.
"Although the narrative is 50 years old, the basic science has not changed," Gschneidner notes. "Our knowledge and understanding is still the same."
For an up-to-date review of the rare earth elements, which is more technical, see the 2012 articles by Karl A. Gschneidner, Jr. and Vitalij K. Pecharsky in the Encyclopedia Britannica (http://www.britannica.com/EBchecked/topic/491579/rare-earth-element). The narrative regarding the entire rare earth group as a whole is over 13,000 words. In addition, there are 17 summaries (between ~400 and ~700 words long) of each rare earth element: