5 Fascinating Facts About Rare Earth Elements That Might Surprise You

Since their discovery over 200 years ago, rare earth elements have become an essential part of our every day lives. From mobile phones and computers, to wind turbine generators and electric vehicle motors, you can find rare earths in several modern technologies today. However, the beginning of their story and subsequent identification is probably the most confusing and complex, yet fascinating of all the elements.

• The discovery of rare earth elements is somewhat of a dispute

  It began around the end of the 18th century when Swedish chemist named Johann Gadolin had isolated the first rare earth element, yttrium, from a heavy black mineral. This was the very first rare earth element to be discovered and ignited the fervent exploration.

  Just nine later, Jons Jacob Berzelius and Wilhelm Hisinger in Sweden and Martin Klaproth in Germany announced almost simultaneously that they had isolated a new element, cerium. This provoked the first of several priority disputes in the pathway to the discovery of rare earth elements.

  The search for rare earth elements constituted an integral part of science in the late 19th century, but several factors made their identification difficult, which prompted the discovery disputes. The similar chemical and physical properties, the tedious methods of separation and purification, and the lack of identification and purity assessments were ultimately to blame. Because of the complexity of the process, and the questionable purity of the samples, many claims being made for new elements were ultimately proved false. While many of the rare earths were discovered almost simultaneously, credit would often fall to the claims that were not only the first to be published, but also substantiated.

  By the end of the 19th century, chemists and mineralogists were able to identify a total of 14 rare earth elements thanks to the advancement in technologies and the development of the periodic table. By 1907, the discovery of the elements lutetium and promethium closed the history of the discovery of REE in the world as these two elements were the last rare earths to be discovered.

• One country is known for the world’s single richest source of rare earths, and it’s not China.

  Sweden, specifically Ytterby, a village on an island outside of Stockholm, is one of chemistry’s most important locations. It was here, in 1787, that a Swedish army officer, Carl Axel Arrhenius, found a scrap of black mineral and sent it to a friend for analysis (see Johann Gadolin from above). It proved to be of singular importance: almost a tenth of the naturally occurring elements in the periodic table would eventually be discovered from rocks identified in that one village.

  In fact, almost all of the rare earth elements can trace their discovery from this modest mine that once supported the local community. The term “Rare Earth Element” was used in the 19th century, based on the discovery of the Ytterby mine, the only deposit of its kind in the world at that time, thus rather rare.

• The Cold War led to the discovery of the U.S.’s first and only rare earth mine, which once actually dominated global production.

  The U.S. once mined rare earths at a large deposit in Mountain Pass, California, a town just 45 miles south of Las Vegas. The deposit was discovered in 1949 by Herbert S. Woodward, Clarence Watkins and P. A. Simon.

  At that time, the world was on a hunt for uranium. Following the bombing of Hiroshima and Nagasaki, the demand for more uranium to produce nuclear weapons increased dramatically. The search for and mining of uranium continued constantly, as the mines attempted to meet the ever-growing demand for the radioactive element during the Cold War arms race with the Soviet Union.

  In Spring of 1949, an engineer arrived in Goodspring, Nevada to give a talk on the search for uranium. Among those present at the talk was Herbert S. Woodward, a local engineer. In reviewing the occurrence of uranium, the speaker mentioned the common association of uranium and cobalt, an element that happened to occur widely in the ores of the Goodspring district. This gave Woodward the idea of searching for uranium with local miners in the nearby areas known to contain cobalt.

  While reviewing some specimens with their Geiger counter, they noticed unusually high radioactivity. Excitedly, the submitted the specimens to the U.S. Bureau of Mines; yet, the test did not indicate the discovery of uranium, but the presence of considerable rare earth oxides. Three years later, an American mining corporation purchased most of the mining claims in the area and began small-scale production in 1952. Production expanded greatly in the 1960s and over the next 30 years the mine supplied most of the worldwide rare earth metals consumption.

• Rare Earth Elements are very cunning…

  The chemical and physical properties of the different rare earth elements are quite similar. They are known to conceal their additional electrons in the atomic equivalent of false-bottomed drawers. So, as you move across the periodic table from Element 59 to 60 to 61, the same basic number of electrons are exposed in each case.

  As a result, it's very, very hard to separate these elements from one another—imagine trying to separate all the spices in your cabinet after they're dumped into one big bowl! They proved such a pain to work with that they found only limited use in industry. However, in the past few decades, some persistent chemists have learned to exploit the subtle differences among rare earth elements to create amazing technology.

• Rare earths are the only elements that dangle below the periodic table instead of sitting where their numbers say they should.

  One reason is practical. Removing them makes the table narrower and less difficult to print on standard size papers and posters. But there are good chemistry-based reasons to separate them, too—because they all act like a single element.

  Normal elements have certain properties based on how many electrons they make available for other elements to react with. Each element adds one electron as its number increases, and this addition of an electron makes the element distinct and easy to separate from its neighbors. However, as explained in #4, rare earth elements do something sneaky…. As you move across the periodic table, same basic number of electrons are exposed in each case, thus concealing additional electrons.

  Interestingly though, these elements contain many unpaired electrons. Because unpaired electrons can spin in either direction, they reveal magnetic moments, which mean these rare earth elements can store large amounts of magnetic energy. In fact, a neodymium magnet (a common rare earth magnet) can store about 18 times more magnetic energy than an iron magnet of the same volume. Rare earth magnets like these are widely used today in many applications, including wind turbines, electric motors, guidance systems on aircraft and missiles, speakers for personal electronics, and computer hard drives.