Periodic Systems of Molecules as Elements of Shchukarev's “Supermatrix”, i.e. the Chemical Element Periodic System

Abstract

Generations of Soviet scientists contributed invaluable insights into molecular classification. Unfortunately, this research is little appreciated in much of the world. Among these workers S. A. Shchukarev was of great importance. His and his followers' legacy includes a host of graphical displays showing enthalpies of formation of gaseous molecules from free atoms DeltaH(a) and standard enthalpies of formation of substances plotted on the atomic number of the central elements, on their oxidation states, their internuclear separations, and other variables for a wide range of molecules. These graphs serve as databases, from which data can be extracted, to moderate precision, visually. We discuss graphs for one very limited set, or "pleiade" (gas-phase oxides of nitrogen), and for three much broader sets, or subsystems (gas-phase fluorides of all main subgroup atoms and oxides of transition-metal atoms in gas-phase and in STP conditions). When dissolved in water, molecules lose their identities but periodicity is echoed in the acids and aquocations that are formed. We show, as an example in tabular form, that redox potentials of high-oxygen acids containing S, Se, and Te change concomitantly with DeltaH(a ) and DeltaH(f) of their hexafluorides. We present graphical evidence that three properties for cations of groups 1-3 (in the short version of the periodic chart) behave similarly and share the periodicity of the elements. One of the properties is related to the ionization potential, which is shown in a tabular example to vary concomitantly with energy of hydration. It was the ultimate goal of S. A. Shchukarev that the transformation of any one graphical database into any other, having different molecules under different conditions, would be made mathematically.

Near Infrared Spectral Studies of Aqueous Solutions of Metal Perchlorates in Groups I A, II A, II B, III A and III B of the Periodic Table

“…The PCA enabled us to reveal the similarities and differences in the concentration dependence of spectra for solutions of studied perchlorates. Our study provides spectral evidence that is in agreement with the prediction by Latysheva et al 32 about the dependence of the characteristics of free atoms in complex solution systems. Thus, the location of the clusters in the diagram in accordance with the position of elements in the Periodic Table is determined by the laws of electron shell structure of metal atoms.…”

Kronecker-Product Periodic Systems of Small Gas-Phase Molecules and the Search for Order in Atomic Ensembles of Any Phase

“…This invitation gave an unparalleled opportunity to explore the subject of molecular periodicity on the side: the periodic table of the elements had been a symbol of national pride and study in Russia for decades and several investigators had considered an extension into the space of diatomic or even larger molecules. Morozov had in 1907 assembled the alkanes into a periodic table [2]; Syrkin had in 1971 published a periodic system of practically the same molecules as those contained in the classification described in Section 4 [7]; and the chemistry faculty at Leningrad State University had for years been assembling molecular data for their eventual classification into a "supermatrix" [21]. There are 16 of them, and the coordinates are different than those of the system built by our group.…”

“…For some time, our group had sought to find more appealing ways to present the 9-block system, beyond the efforts described in Section 5.6. This search eventually resulted in the computer plotting of isometric stick (or "drop-down") graphs for molecular structure data on all of the main-group areas for diatomic molecules, which in turn resulted in isometric shaded drawings of the surfaces for D o o [2,12], r e [2,12,42], e [2,21] and IP. Stick graphs were also plotted for fixed-group molecules [ch.…”

“…A group of Russian chemists at LSU had long hoped to describe all molecules in such a way that the properties of one set of them, in a given phase, could be related to the properties and phase of some other set of molecules by mathematical techniques [21]. They considered that the techniques were not yet available, and in order to prepare for the day when they were available, the chemists embarked on a massive experimental data-collection enterprise.…”

Do triatomic molecules echo atomic periodicity?

“…Only after triatomics containing atoms from additional periods are treated will it be possible to test the presence of periodicity. The spectroscopic constant ν 1 was chosen partly with the hope that it may be distributed in diatomic molecular space as smoothly as diatomicmolecular vibration frequencies in diatomic molecular space [9]. This investigation does not address whether any particular free triatomic need exist in the observable universe or in experimental apparatus.…”