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The problem of "zero" in the works of Mendeleev
The problem of "zero" in the works of Mendeleev

… The more I had to think about the nature of chemical elements, the more I deviated both from the classical concept of primary matter, and from the hope of achieving the desired comprehension of the nature of elements by studying electrical and light phenomena, and each time more urgently and more clearly I realized that earlier this or first it is necessary to get a more real idea of ​​the "mass" and of the "ether" than now.

D. I. Mendeleev

In January 1904, Petersburg Leaflet No. 5, on the occasion of the 70th birthday of Dmitry Ivanovich Mendeleev, published an interview with him. When asked what kind of scientific research he is currently engaged in, the scientist replied: "They are aimed exclusively at confirming the theory I put forward in the past year, or, rather, attempts, of a chemical understanding of the world ether."

What is this theory that we know so little about?

DI Mendeleev finished his article "An Attempt at a Chemical Understanding of the World Ether" in October 1902, and published it in January 1903 in No. 1-4 of the "Bulletin and Library of Self-Education". In May 1904, in a letter to the famous astronomer Simon Newcomb, he announced that in the near future he was going to write an article "on modern ideas about the complexity of chemical elements and about electrons …"


Portrait of D. I. Mendeleev by I. N. Kramskoy. The year is 1878. The idea of ​​"chemical" ether, which, according to D. I. Mendeleev, is closely related to the periodic table of elements, the scientist nurtured since the 1870s.

About the complexity of chemical elements and about electrons - this is understandable to the modern reader, but the world ether? Now even schoolchildren know that this idea has been abandoned by science. Therefore, probably, one of the last works of Mendeleev is very rarely commented on, practically nowhere mentioned, and it is generally difficult to find it. In many scientific and educational libraries in the multivolume "Works" of DI Mendeleev, volume 2 is missing, which contains the chapter "Attempt at a chemical understanding of the world ether". Sometimes one even gets the impression that they are somehow bashfully trying to blot out this "curious" work from the scientist's heritage. It seems that many condescendingly think that the great Mendeleev in his old age may have exceeded the level of his competence.

But let's not jump to conclusions. DI Mendeleev nurtured this "embarrassing" theory for almost his entire creative life. Two years after the discovery of the periodic system (Mendeleev was not yet 40 years old) on an imprint from "Fundamentals of Chemistry" by his hand, near the hydrogen symbol, an inscription was made, which can be deciphered as follows: "Ether is the lightest of all, millions of times." Apparently, "ether" seemed to Mendeleev to be the lightest chemical element.

“Since the 70s, the question has persistently stuck in me: what is ether in the chemical sense? It is closely connected with the periodic system of elements, and was excited by it in me, but only now I dare to talk about it."

So, the chemical element of the ether - the element of the ether - the atomicity of the ether - the discreteness of the ether. This is not the ether that modern physics has discarded as an unnecessary crutch. Let's open the dictionary:

"Ether (Greek Aither - a hypothetical material medium filling space) … In classical physics, ether was understood as a homogeneous, mechanical, elastic medium filling absolute Newtonian space" (Philosophical Dictionary / Ed. M. M. Rosenthal. - M., 1975).

In the classical definition of ether, the emphasis is on homogeneity or continuity. The ether, about which Mendeleev speaks, consists of elements, it is atomic, it is inhomogeneous, it is discontinuous and discrete.It has a structure.

Dmitry Ivanovich's interest in the ether problem in the 1870s is closely related to the periodic system (“it was this that excited me in me”) and the subsequent work on the study of gases. “At first I also believed that ether is the sum of the most rarefied gases in the limiting state. The experiments were carried out by me at low pressures - to get hints of an answer."


But these works did not satisfy him: “… the idea of ​​the world ether as the ultimate rarefaction of vapors and gases does not withstand even the first bouts of thoughtfulness - due to the fact that the ether cannot be imagined other than as a substance, penetrating everything and everywhere; This is not typical for vapors and gases”.

The detailed development of the "chemical concept of the world ether" began with the discovery of inert gases. DI Mendeleev predicted many new elements, but inert gases were unexpected even for him. He did not immediately accept this discovery, not without an internal struggle, and disagreed with most chemists about the location of inert gases in the periodic system. Where should they be located? Modern chemists, without hesitation, will say: of course, in the VIII group. And Mendeleev categorically insisted on the existence of the zero group. Inert gases are so different from other elements that they had a place somewhere on the side of the system. It seemed, what a difference, on the right (VIII group) or left (zero group) edge they will be. It seems to us completely unprincipled, especially for those times when they did not know the electronic structure of atoms, although even now we only delude ourselves that we know. Mendeleev thought differently. Putting inert gases on the right means getting a whole series of voids between hydrogen and helium. It was a challenge to look for new elements between hydrogen and helium! Maybe there is a halogen lighter than fluorine (Mendeleev admitted the probability of the existence of such a halogen, assuming that helium is really in group VIII) or other light elements between hydrogen and helium? They are not there, so the place of inert gases is on the left, in the zero group! Moreover, their valency is more likely to be zero than VIII. And the quantitative ratio of atomic weights unambiguously indicates the position of inert gases on the left, at the beginning of each row.

“This position of the argon analogs in the zero group is a strictly logical consequence of understanding the periodic law,” asserted DI Mendeleev.


At the suggestion of William Ramsay, Mendeleev includes the zero group in the periodic table, leaving room for elements lighter than hydrogen.

It becomes clear why Dmitry Ivanovich insisted on the existence of the zero group; his mentions of a hypothetical halogen lighter than fluorine are understandable; hence, his search for an element lighter than hydrogen is even understandable, the existence of which he had long thought: “It never occurred to me that a number of elements should begin with hydrogen”. "To deprive hydrogen of that initial position, which it has long occupied, and to make it wait for elements with even less than that of hydrogen, the weight of an atom, which I have always believed in" - these are the scientist's innermost thoughts, which he hid until the periodic law was finally will not be approved. “I had thoughts that earlier than hydrogen one could expect elements with an atomic weight of less than 1, but I did not dare to express myself in this sense because of the fortune-telling of the assumption and especially because then I was careful not to spoil the impression of the proposed new system, if its appearance will be accompanied by such assumptions as about the lightest elements than hydrogen."

Precisely in the system with a zero group that he defended, which was first proposed by the Belgian scientist Leo Herrera in 1900 at a meeting of the Belgian Royal Academy of Sciences (Academie royale de Belgique), hydrogen may not seem to be the first, since it inevitably appears in front of it free space for an ultralight element - maybe this is the "ether element"?

“Now, when it began not to be subject to the slightest doubt that before group I, in which hydrogen should be placed, there is a zero group, whose representatives have atomic weights less than those of group I elements, it seems to me impossible to deny the existence of elements lighter than hydrogen,”wrote Dmitry Ivanovich.

In the law he discovered, Mendeleev tries to understand from the physical point of view the nature of mass as the main characteristic of matter. Finding out the physical foundations of gravitation (about how much effort and time he devoted to this problem, we also know little), closely related to the concept of the world ether as a "transmitting" medium, he is looking for the lightest element. However, the results of the experiments of the 1870s, which boiled down to proving that "ether is the sum of the rarest gases", did not satisfy Mendeleev. For some time he stopped research in this direction, did not write anywhere, but, apparently, never forgot about them.

At the end of his life, in search of answers to questions concerning the deep properties of matter, he again turns to the "world ether", with the help of which he tries to penetrate into the nature of the basic concept of natural science in the 19th century (and even the 20th, and even the 21st centuries) - masses, as well as to give explanations for new discoveries and, above all, radioactivity. The main idea of ​​Mendeleev is as follows: “A real understanding of the ether cannot be achieved by ignoring its chemistry and not considering it an elementary substance; elementary substances are now inconceivable without the subordination of their periodic legitimacy. " Describing the world ether, Mendeleev considers it, “firstly, the lightest of all elements, both in density and atomic weight, secondly, the fastest moving gas, and thirdly, the least capable of forming with any other atoms or particles of certain any strong compounds and, fourthly, an element that is everywhere widespread and all-pervading."

The weight of an atom of this hypothetical element X, according to Mendeleev's calculations, can range from 5.3 × 10-11 up to 9.6 × 10-7 (if the atomic weight of H is 1). To estimate the mass of a hypothetical element, he draws on knowledge from the field of mechanics and astronomy. Element X received its place in the periodic table in the zero period of the zero group, as the lightest analogue of inert gases. (Mendeleev calls this element "Newtonium".) In addition, Dmitry Ivanovich admitted the existence of another element lighter than hydrogen - the element Y, coronium (presumably the lines of coronium were recorded in the spectrum of the solar corona during the eclipse of the Sun in 1869; the discovery of helium on Earth provided a basis consider the existence of this element as real). At the same time, Mendeleev repeatedly emphasized the hypothetical nature of the elements X and Y and did not include them in the tables of elements of the 7th and 8th editions of Fundamentals of Chemistry.

Scientific exactingness and responsibility in Mendeleev's works do not need comments. But, as we can see, if the logic of the search required it, he boldly put forward the most unusual hypotheses. All the predictions made by him on the basis of the periodic law (the existence of 12 elements unknown at that time, as well as corrections of the atomic masses of the elements), were brilliantly confirmed.

“When I applied the periodic law to the analogs of boron, aluminum and silicon, I was 33 years younger, I was fully confident that sooner or later what was foreseen must certainly be justified, because everything was clearly visible to me. The excuse came sooner than I could have hoped. Then I did not risk it, now I risk it. It takes determination. It came when I saw radioactive phenomena … and when I realized that it was no longer possible for me to postpone and that perhaps my imperfect thoughts would lead someone on a path more correct than that possible, which seems to my weakening vision.

So, is this the first major mistake, maybe even a deep delusion of a great scientist, as many now believe, or just a regrettable misunderstanding of genius by his incapacitated students?

At the beginning of the 20th century, not only Mendeleev, but also many physicists and chemists believed in the existence of "ether". However, after the creation of the special and general theory of relativity by Albert Einstein, this belief began to fade. It is generally accepted that by the 1930s the problem of "ether" no longer existed, and the question of elements lighter than hydrogen disappeared by itself. But, again, the problem of the classical ether, homogeneous ether has disappeared, but the structural ether (Mendeleev's ether) is quite alive, only it is now called the structural vacuum or the physical vacuum of Dirac. So the question is only in terminology.

Let's go back to the elements lighter than hydrogen. Any chemist knows homologous series and how their first members behave, especially the first. The first is always special. He always stands out strongly from the general row. Hydrogen is placed in both groups I and VII (it is somewhat similar to both alkali metals and halogens at the same time). So, hydrogen is not like the first … In search of the real elements of the zero period, we find ourselves in a completely different world, and it seems that this is the world of elementary particles.

The understanding of chemistry as a science of qualitative changes, according to many researchers, is most clearly manifested in the periodic table, and at the very beginning of the system it is simply dazzlingly bright. “The most common simple bodies in nature have a low atomic weight, and all elements with a low atomic weight are characterized by sharpness of properties. Therefore, they are typical elements ", and as one approaches the" zero point ", fantastic" sharp "qualitative leaps should occur, which follows from its singular nature, since" … here is not only the edge of the system, but also typical elements, and therefore we can expect originality and peculiarities."

We often talk about the fundamental nature of the periodic law, but it seems that we do not really understand this. Let us repeat Mendeleev: "The essence of the concepts that cause the periodic law lies in the general physicochemical principle of correspondence, transformability and equivalence of the forces of nature."


The entry made by DI Mendeleev's hand on the page with the periodic system of 1871 in his textbook "Fundamentals of Chemistry" in 1871, stored in the scientist's archive: "Ether is the lightest of all, a million times."

In conclusion, I would like to quote the words of Dmitry Ivanovich:

“I look at my far from completeness attempt to understand the nature of the world ether from a really chemical point of view, no more than an expression of the sum of the impressions accumulated in me, escaping solely for the reason that I do not want the thoughts inspired by reality to disappear. It is likely that similar thoughts have occurred to many, but until they are stated, they easily and often disappear and do not develop, do not entail a gradual accumulation of certainty, which alone remains. If they contain at least a part of the natural truth that we are all looking for, my attempt is not in vain, it will be worked out, supplemented and corrected, and if my thought is incorrect in its foundations, its presentation, after one or another kind of refutation, will prevent others from repeating. I know of no other way for a slow but steady movement forward."

PHYSICAL VACUUM - in the modern view, the ground state of quantized fields, a kind of medium with zero electric charge, momentum, angular momentum and other quantum numbers. The fields have minimal energy, but they are subject to fluctuations with large amplitude. The emergence of quantum ideas led to the creation of a universal picture of a single structure of matter. Instead of fields and particles of classical physics, they now consider single physical objects - quantum fields in four-dimensional space-time, one for each "classical" field (electric, magnetic, etc.) and for each type of particles.For example, the Dirac vacuum is a field of particles with spin ½ (electrons, positrons, muons, quarks, etc.). Each single interaction of particles or fields is the result of the exchange of quanta of these fields at a point in space-time. From some points of view, the physical vacuum manifests the properties of the material environment, giving reason to consider it "modern ether".

D. Mendeleev. An attempt at a chemical understanding of the ether. 1905.pdf Fundamentals of Chemistry. Part one. 1949. Mendeleev D.I.djvu Fundamentals of Chemistry. Part two. 1949. Mendeleev D.I.djvu Articles on the topic:

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