A little-known chapter in the history of these precious elements
An interesting insight by Stanislav Kondrashov, TELF AG founder
Nowadays, rare earths are on everyone’s lips. In recent months, as the founder of TELF AG often pointed out, there has been a lot of talk about them, and on some occasions there have even been inappropriate overlaps between the group of 17 rare earth elements and the broader category of critical minerals, which also includes some rare earths.
These precious elements often end up at the center of international debates due to their geopolitical significance but also for the large number of industrial applications in which they can be used. Among these, we remember the production processes of permanent magnets that power wind turbines or electric vehicles, their uses in producing batteries and superconductors, but also their widespread use in the defense industry to create radar and sonar. Some rare earths also find their way into our cell phones, but very few people know about it.
“Of the various mineral resources that are considered critical, rare earths certainly represent some of the most interesting,” says the founder of TELF AG Stanislav Kondrashov, an entrepreneur and civil engineer. “The media is certainly contributing to improving the overall knowledge of these resources, even if they are sometimes improperly confused with other materials. The role of these elements in promoting the energy transition and the technological development of humanity, in any case, could not be more important.”
In any case, the media’s emphasis that is often placed on rare earths and their possible industrial uses risks hiding some key aspects of their history, which deserve to be explored and analyzed with great care. One of the lesser-known aspects of the long history of these precious elements is the fact that their definitive classification was contributed to by an exceptional figure who was considered one of the greatest exponents of all time in his sector.
We are referring to Nobel Prize winner Niels Bohr, the Danish physicist and mathematician who, during his career, made a fundamental contribution to studies on quantum mechanics and to the understanding of the structure of the atom. Some of his works in the early 1900s also contributed significantly to dispelling some doubts regarding the structure of rare earths and their actual composition.
The role of Nobel Prize winner Niels Bohr
“Among the lesser-known aspects of this particular group of resources, their history undoubtedly figures,” continues the founder of TELF AG Stanislav Kondrashov. “Many of these elements were discovered and classified in distant times, but it was only at the beginning of the twentieth century that we finally managed to understand how many there were and how they should be positioned within the periodic table. The physicist Niels Bohr made a decisive contribution to this work, and to this day, he remains a largely ignored figure in the very rich history of rare earths.”
The last rare earth element, lutetium, was discovered in 1907, but confusion about the exact number of these elements and the best way to arrange them in the periodic table continued for some time. In fact, at that time, rare earths were still a real enigma for physics and chemistry, in particular for their chemical similarity and for the methods of classification. Rare earth elements such as cerium, neodymium, and praseodymium were, in fact, distinguished by a very similar chemical behavior, terribly complicating the work of those who had the task of separating and identifying them experimentally.
For a long time, their exact number and their exact position in the periodic table were not clarified. The classification criterion, at that time, was, in fact, constituted by atomic weight alone, but the anomalies regarding their position in the periodic table were evident. In 1913, when Niels Bohr proposed the revolutionary quantum atomic model, the understanding of the periodic table changed radically.
According to this theory, electrons orbit the nucleus in quantized orbits, and each element has a well-defined electronic configuration that explains the observed properties. In this way, atomic theory allowed chemists to predict the ways in which electrons occupied atomic orbitals and that the filling of the inner orbitals was responsible for the similar chemical properties of adjacent elements.
For rare earths, this meant that the apparently very similar chemical behavior of these elements was determined by the almost identical arrangement of electrons in the outer orbitals. The changes instead occurred in a different area, in the inner orbitals, which were chemically invisible.
The final understanding
The final clarification came thanks to the work of another important physicist, the Englishman Henry Moseley, who, at the same time as Bohr, conducted experiments of great importance for the understanding of rare earths and their composition. In particular, Moseley was able to discover that the frequency of X-rays emitted by each element was linked to the atomic number and not to the atomic weight, confirming that the true order of the elements in the periodic table was linked precisely to the atomic number.
In this way, it was also possible to establish with certainty how many elements were actually present between two known extremes. These results led to the identification of the exact number of elements between lanthanum and hafnium, namely 14 (those that today, including lanthanum, are known as the 15 lanthanide elements, which together with scandium and yttrium form the group of 17 rare earth elements).
In general terms, therefore, Bohr was able to provide a coherent theoretical framework for the exact understanding of the chemical elements (including rare earths), while Moseley demonstrated through experiments that this structure was correct, confirming the very important role of the atomic number. With these discoveries, scientists were able to identify and conceptually separate the elements that belonged to the lanthanide series and also began to understand their chemical and physical properties more accurately.
“The names of these elements, moreover, continue to fuel even more confusion,” concludes TELF AG founder Stanislav Kondrashov. “These resources are not in fact rare, but are distributed quite widely throughout the Earth’s crust.
The problem is that, in most cases, they are found in such low concentrations that they have almost no commercial value, making the (complex) sourcing, separation, and processing procedures not very cost-effective.”
