On the Formulation and Essence of the Law of Chemical Shares

Ya. I. Mikhailenko.

(With 4 figures in the text).

1. Analysis of the compound of hydrogen with oxygen—water—shows that in water, for 1 part by weight of hydrogen there are 8 parts by weight of oxygen.

Analysis of the compound of oxygen with iron—iron oxide—shows that in iron oxide, for 8 parts by weight of oxygen there are 28 parts by weight of iron.

Let us analyze the compound of iron with bromine—ferrous bromide; we shall find that for 28 parts by weight of iron in it there are 80 parts by weight of bromine.

We shall continue the analyses further and shall find: in the compound of bromine with iron—ferric bromide—for 80 parts by weight of bromine there are 18.7 parts by weight of iron; in the compound of iron with chlorine—ferric chloride—for 18.7 parts by weight of iron there are 35.5 parts by weight of chlorine; in the compound of chlorine with mercury—mercuric chloride—for 35.5 parts by weight of chlorine there are 100 parts by weight of mercury; in the compound of mercury with oxygen—mercuric oxide—for 100 parts by weight of mercury there are 8 parts by weight of oxygen; in the compound of oxygen with potassium—potassium oxide—for 8 parts by weight of oxygen there are 39 parts by weight of potassium; in the compound of potassium with iodine—potassium iodide—for 39 parts by weight of potassium there are 127 parts by weight of iodine; in the compound of iodine with lead—lead iodide—for 127 parts by weight of iodine there are 103.4 parts by weight of lead; in the compound of lead with sulfur—lead sulfide—for 103.4 parts by weight of lead there are 16 parts by weight of sulfur.

In what weight ratios do sulfur and hydrogen combine?

There is no need to perform an experiment—they combine in the ratio 16:1.

This is the law of chemical shares, and the numbers: 1:8:28:80 and 18.7, etc., are the chemical shares of the corresponding elements.

Let us write down our analyzed pairs and the numbers obtained in one row, and, according to the law of shares, close it. We obtain Fig. (1), which is the graphic representation of the law of shares.

Fig. 1.

2. Let us examine this graph more closely (Fig. 1). Suppose it is necessary to know in what weight ratios bromine and hydrogen combine. By drawing a line connecting the elements hydrogen and bromine, we limit our experimental row to only four members. According to the law of shares this row closes, i.e., this means that hydrogen and bromine, if they form the compound hydrogen | bromine, will be present in this compound in the ratio 1:80. Indeed, in this ratio hydrogen and bromine form the compound hydrogen bromide.

To learn in what weight ratio oxygen combines with lead, it is necessary to close the experimental row with the members: oxygen (8) and lead (103.4). The numbers 8 and 103.4 give the sought ratio. Indeed, in the compound lead oxide, for 8 parts by weight of oxygen there are 103.4 parts by weight of lead.

To find in what weight ratio sulfur and iron II combine, it is necessary to close the row: sulfur | hydrogen | oxygen | iron II... and so on, and so on. | That is, in order to know in what weight ratios any two elements of the row combine, only one completed experimental row is sufficient.

Otherwise, the separate members of our experimental row may be rearranged in any way—the experimental reliability of the row is not thereby impaired. For example, let us move lead into the place of iron II. We obtain the pairs:

| Oxygen | lead, | lead | bromine and pairs: iodine | iron II, |
|---:|---:|---:|---:|---:|---:|
| 8 | 103.4 | 103.4 | 80 | 127 | 28 |

Indeed, these pairs form chemical compounds precisely in these weight ratios.

Let us interchange here and there the elements potassium and chlorine. We shall obtain, among others, the pairs: iron III | potassium and chlorine | iodine.

The compound ClJ is known, but the compound iron III | potassium may also not yet have been obtained. All the same, if at some time it were obtained, then the ratio between iron and potassium in this compound would be expressed by the numbers 18.7:39.

Let us interchange hydrogen with sulfur. We shall obtain the pair sulfur | oxygen.

But experiment shows that in the compound sulfur | oxygen—sulfur sesquioxide—the ratio between sulfur and oxygen will be 10.66:8; in the compound sulfur | oxygen—sulfur dioxide the ratio between sulfur and oxygen will be: 8:8, and in the compound sulfur | oxygen—sulfuric anhydride: 5.33:8. A compound formed in the ratio 16:8 is as yet unknown.

There is, however, no contradiction of the law of shares here. This happens because our experimental series of shares is not complete. If it were complete, then, besides sulfur II with share 16, there would also enter into it: sulfur IV with share 8 and sulfur VI with share 5.33. The compound of sulfur and oxygen in the ratio 16:8 is unknown only because the conditions have not been found under which it is stable.

Thus, in the complete graph of chemical shares, we may change the order of the terms in any way we like—the chemical share of an element does not depend on the nature of the element with which it forms a pair.

The emblem of the law of chemical shares is a closed ring. One involuntarily recalls the well-known emblem of the alchemists—the serpent swallowing its own tail.

3. The numbers of the chemical shares of the graph (Fig. 1) were obtained by a series of analyses of separate pairs and were only written in one series. Will these numbers remain the same if the elements are bound in a molecule? Experiment shows that they will remain the same. For example, the compound lead | oxygen—lead oxide and the compound hydrogen | oxygen—water give the compound lead | oxygen | hydrogen | oxygen—lead hydroxide.

The magnitudes of the shares remain the same. In this compound, for one share of lead there are two shares of oxygen.

compound: potassium | oxygen—potassium oxide, and compound

give the compound:

Chlorine V enters into this compound; namely, chlorine share \(7.1 = 35.5 : 5\).

In the compound methyl chloride we have the chain:

Thus, if the elements form a molecule, their chemical shares remain the same. Otherwise, each molecule represents a part of the graph of the shares, and, obviously, the emblem of the molecule will be the same as that of the law of shares—namely, a closed ring.

For example, let us represent the molecule of lead hydroxide as a closed chain (Fig. 2).

Fig. 2.

Let us represent the molecule of methyl chloride as a closed chain (Fig. 3), and so on.

Fig. 3.

1. To clarify the essence of the law of shares, as is known, the hypothesis of indivisible atoms was proposed, which to this day may be considered generally accepted.

In 1900, in the article “On the Formulation of the Simplest Laws on the Weight Ratios in Which Elements Enter into Chemical Interaction; on the Indivisibility of the Chemical Share” (Kiev Univ. Izv., 1900), I pointed out that the atomic hypothesis is not the only scheme for the law of shares, and there I also gave other possible schemes. In the article “On the Question of the Derivation of the Stoichiometric Laws of Chemistry without the Aid of the Atomic Hypothesis” (Zh. R. F. Kh. O., 36, 1120, 1904) I showed that the law of shares has exactly the same form as the second law of Volta and the law of the distribution of a substance between immiscible liquids.

Let us examine more closely this last analogy in connection with the formulation of the law of shares given above.

Let immiscible liquids be poured into an annular vessel: for example, \(A, B, C, D, E, F\). Let some substance \(Z\) be dissolved in all these liquids. When equilibrium is established, let the spatial concentration of the substance \(Z\) in solvent \(A\) be \(a\), in solvent \(B\)—\(b\), in solvent \(C\)—\(c\), in solvent \(D\)—\(d\), in solvent \(E\)—\(e\), in solvent \(F\)—\(f\). (Fig. 4).

As is known, according to the second law of thermodynamics, in the equilibrium system of Fig. (4) we may mentally interchange solvent \(A\) with, for example, \(D\), or in general with any other solution of the system—and from this the equilibrium will not be disturbed. Hence it follows:

Let, for example, we need to know how the substance \(Z\) will be distributed between the solvents \(A\) and \(C\), under the condition that the spatial concentration of \(Z\) in solvent \(A\) is \(a\) grams?

Fig. 4.

We mentally interchange the solvents \(A\) and \(D\). Since the equilibrium will not thereby be disturbed, this means that between the solvents \(A\) and \(C\) the substance \(Z\) will be distributed in the ratio \(a : c\).

Or else we shall close the ring, limiting ourselves to three solvents: \(A, B\), and \(C\). Since the equilibrium will not be disturbed in this case either, the distribution coefficient between \(A\) and \(C\) will be \(a : c\). We can also proceed as follows: dissolve in solvent \((A)\) so much of substance \(Z\) that in a unit of volume there is \(a\) grams of substance \(Z\), and determine experimentally the concentration of substance \(Z\) in solvent \((B)\) at which this latter solution is in equilibrium with solution \(A\). Let the experiment give the number—\(b\) grams.

Take solution \(B\) (containing in a unit of volume \(b\) grams of substance \(Z\)) and determine experimentally the concentration of substance \(Z\) in solvent \(C\) at which this latter solution is in equilibrium with solution \(B\). Let the experiment give the number \(c\) grams. There is no need to make a new experiment. The pair \(A \mid C\) will constitute the equilibrium system

\[ \frac{a}{c} \]

The distribution coefficient of substance \(Z\) between the solvents \(A\) and \(C\) will be \(a : c\).

Thus, the analogy between the law of distribution of a substance between immiscible liquids and the law of chemical shares is evident.

1. The analogy between the law of chemical shares and the law of distribution between immiscible liquids makes it possible to construct a scheme of a chemical compound different from the usual atomic scheme. Namely:

A chemical compound is a closed equilibrium system. In it one must distinguish a medium of varying degrees of compaction and the primordial matter that permeates this medium. The primordial matter permeates not only the individual chemical individuals, but also the space between them. This single, all-permeating and all-filling primordial matter binds all chemical individuals into one equilibrium system, analogous to a system consisting of a large number of contiguous phases.

Our world is an unbroken chain of chemical compounds contiguous with one another, as though one enormous molecule, whose emblem is the emblem of the law of shares—the alchemical serpent devouring its own tail.

Ya. Mikhailenko.

Tomsk, November 30, 1909.