The “Chemical Mechanics” of the Periodic Table (original) (raw)
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150 Years of the Periodic Table, Perspectives on the History of Chemistry, C. J. Giunta et al. (eds.), , 2021
The historical development of the theoretical account of the periodic table provided by theoretical physics is reviewed, beginning with discoveries made at the start of the twentieth century. The article highlights the attempts to theoretically explain several features of the periodic table including the well-known period doubling or Madelung rule of orbital occupation. The account includes more recent group theoretical approaches which go beyond quantum mechanics and seek an explanation based in the underlying symmetry of the periodic table and how this symmetry is broken to produce the diversity of atoms that we are familiar with. The approach taken is one of seeking a global solution to such questions rather than merely solving the equations of quantum mechanics for each individual case.
Periodic table of elements, Mendeleev's periodic table: history, achievements and problems
2019
This paper, devoted to the yubilee of Mendeleev’s table, deals with a set of historical and physico-chemical problems related it. Basing on the evolutional approach to the development of the concept of “elements and structure” and up to the appearance of the notion “complexity” we discuss the applicability of Mendeleev’s table to the understanding of modern aspects of science such as “nano”, “fractals”, “synergetics” and “hirality”. The problems which are open for further research are revealed and the particular importance of their development for the condensed matter science of living and nonliving matter is pointed out.
The Physics behind Chemistry and the Periodic Table
Chemical Reviews, 2012
A classical example on relativistic effects in chemistry is the nobility, trivalency, 6 and yellow color of gold. 3,7,8 Another one is the crystal structure of mercury 9 and probably also the low melting-point of mercury. 2 No explicit R/NR (relativistic versus non-relativistic) studies on liquid mercury seem to exist yet. A third, new example is the lead-acid battery. It has just been calculated that, of its 2.1 Volts per cell, over 1.7 Volts come from relativistic effects. 10 Without relativity, cars would not start. Numerous further examples exist. Typical ways of including relativity are the use of pseudopotentials or transformed, approximate Dirac Hamiltonians. Both can be calibrated against full-Dirac benchmarks. For some recent summaries on the methodology we quote Schwerdtfeger, 11,12 Hess, 13 Hirao and Ishikawa, 14 Dyall and Faegri, 15 Grant, 16 Reiher and Wolf, 17 or Barysz and Ishikawa. 18 The next physical level brings in the quantum electrodynamical (QED) effects. For lightelement problems, such as the hydrogen-atom Lamb shift, precise properties of the hydrogen molecules, or the spectra of the lithium atom, all these effects are already clearly seen, because the accuracy of both theory and experiments is very high. Likewise, the QED effects are conspicuous for highly ionized, heavy, few-electron atoms, such as hydrogenlike gold. For neutral or nearly neutral systems, beyond Li or so, only one order-of-magnitude improvement of the computational accuracy, mainly the treatment of electron correlation with adequate basis sets, is estimated to separate the QED effects from being observed in head-on comparisons of theory and experiment. Examples on such cases are the vibrations of the water molecule, 19 or the ionization potential of the gold atom. 20-22 And, that may have been "the last train from physics to chemistry" concerning the fundamental interparticle interactions because, of the possible further terms, parity non-conservation (PNC) 23,24 splittings are estimated to lie over ten powers of ten further down. 25 Like magnetic resonance parameters, the PNC effects can be directly observed. Apart from being a physical challenge, both these effects give new information on molecules, but they are expected to be far too small to influence molecular structures or normal chemical energetics.
The Chemical Space from Which the Periodic System Arose
Mendeleev came across with his first attempt to a periodic system by classifying and ordering the known elements by 1869. Order and similarity were based on knowledge of chemical compounds, which gathered together constitute the chemical space by 1869. Despite its importance, very little is known about the size and diversity of this space and even less is known about its influence upon Mendeleev's periodic system. Here we show, by analysing 11.484 substances reported in the scientific literature up to 1869 and stored in Reaxys database, that 80\% of the space was accounted by 12 elements, oxygen and hydrogen being those with most compounds. We found that the space included more than 2,000 combinations of elements, of which 5\%, made of organogenic elements, gathered half of the substances of the space. By exploring the temporal report of compounds containing typical molecular fragments, we found that Meyer's and Mendeleev's available chemical space had a balance of organ...