Mendeleev’s discovery marked a momentous turning point in the study of chemistry and for science. A discovery that was the result of a vision – perhaps born out of a dream – that simplifies complexity.

If today we are able to speak about chemistry of materials and green chemistry in a schematic and precise way, we owe much of the credit to the vision of a Professor from St. Petersburg. A “visionary” professor. But who can be considered a visionary? Why is this word often used alongside the names of people who revolutionized the traditional knowledge in their field of expertise? There are many artists, entrepreneurs, philosophers, and scientists who have been called visionaries. Let’s start by saying that the word vision comes directly from the Latin word “video”, which means to see. But we all see reality. So then, we must investigate further to understand what a visionary sees. His ability is in discerning something that is not immediately apparent to anyone else because he is able to glimpse what lies beyond it and acquire a new perception of it, which allows him to examine things in a completely different way: an enhanced meta-vision that allows him to make unpredictable correlations and connections. Therefore, a visionary is one who simplifies complexity and, through his own imagination, is able to bring order to it and envision unexpected outcomes. In other words, it is someone who, thanks to his vision, is not afraid to ask very complex questions to which he can find rational and logical answers.

Visionaries from another time

Among the most challenging questions that the earliest visionaries attempted to answer is: how can the multiplicity of the natural world be reduced to a finite number of fundamental elements? We must go back to the fifth century BC when the philosopher Empedocles identified four elements from which every substance originates: fire ( ), earth ( ), air ( ) and water ( ); then in the work Timaeus, Plato associates one of the “platonic” solids to each of them: the tetrahedron to fire, the cube to earth, the octahedron to air, the icosahedron to water. These geometric shapes represent the emblem of beauty and perfection, the combination of which forms all the objects of the natural world. However, for Aristotle this was not enough: he added a fifth element he called ether that constitutes the matter of the celestial spheres.

The creative turn of Mendeleev

Over time and through the centuries, several attempts were made to master the order of matter, but we had to wait until the cold morning of February 17, 1869 for the discovery that would change the history of chemistry and its elements forever. The person responsible was a teacher at St. Petersburg University, Professor Dmitry Ivanovich Mendeleev. There was a blizzard outside, and the professor didn’t have any classes that day; he was supposed to visit some dairy farms to study ways to improve fermentation processes, but the bad weather discouraged him. So, deciding to stay in his studio, he went back to thinking about an old project of his, in which he was trying to establish a definitive arrangement of the known elements according to their weight and valence. He started by trying various combinations, quickly written on the back of an envelope: this happened while he was having a cup of tea, which left a ring on the document (which is still kept at the University of St. Petersburg today.) But there was not enough space on it, so he began to make other attempts on a myriad of other sheets, which have also been passed down to us. It is said that Mendeleev was a lover of the card game solitaire: this gave him the idea to write the name, atomic weight and valence of a single element on each sheet of paper, as if it was the card of a deck. And so, he created 63 cards, each one with the properties of an element on it. Exhausted, he went to sleep. Legend has it that Mendeleev confided what had happened during his sleep to his friend Aleksandrovich Inostrantsev who later revealed: the scientist dreamt that all his cards were swirling around wildly. Then they all stopped and the answer appeared.

Mendeleev woke up with a jolt, ran to the table and carried out what has been christened as “chemical solitaire”. He arranged his cards in this way: the rows held groups of elements with similar properties, the columns held the “periods” in which the elements are ordered, according to their increasing atomic weight. The table of elements was born, based on the discovery of the periodic law of the elements. But Mendeleev’s great intuition and vision went even further: he understood that the scheme had to include “empty boxes” where future elements that were still unknown could be inserted. With his table Mendeleev foresaw future discoveries, inventing a theoretical tool that not only revolutionized the existing knowledge of the time – cataloguing the elements that were known up to then in an effective and functional way – but above all it made it possible to make exact predictions by leaving room for new discoveries.

The role of imagination in scientific discovery

Mendeleev was referred to as “the Copernicus of chemistry” by John D. Bernal, a historian of science. His discovery highlights the role of imagination in the path of science and the importance of creativity in chemistry: his periodic table is the epitome of success in the attempt to transform multiplicity into a finite number, and a consistent universal law that makes it possible to order and predict even what will be discovered in the future. It is a diagram that has become a guide, a new alphabet of chemistry that can be used to coin new words: in fact, Gallium would be cataloged in the following decades, which Mendeleev had already predicted, calling it eka-aluminum, and then similar experiments were conducted on elements of the same groups and periods, which helped to form a more complete picture of the behavior of matter. In effect, Mendeleev showed that intuition, that moment of eureka, makes no distinction between science and art.

Vision can be anywhere.