Gilbert Newton Lewis: His influence on physical-organic chemists at Berkeley

Abstract

There will be a review of the historical contributions of Gilbert N.Lewis to science and a discussion of the influence of Lewis on the research of the members of the physical-organic staff at Berkeley, including Melvin Calvin, during the twenties, thirties and forties. Some specific examples will be discussed. Also, the effect of Lewis, his science and administra tive concepts in the creation of excellence in a department of chemistry will be reviewed.

The Lewis legacy: The chemical bond—A territory and heartland of chemistry

“…This work has eventually had its greatest impact in chemistry through the work of Irving Langmuir,19 who very ably articulated the Lewis concept, coining new and catchy terms 20. Another important influence of the Lewis ideas was on the understanding of reaction mechanisms as established by the English School of Lapworth, Robinson, Lowry, and Ingold 17, 18. This has eventually led to the development of the science of physical organic chemistry,21 which rules mechanistic thinking even today (even though the science itself as an active discipline is no more with us …).…”

“…In Pauling's work, the long sought for Allgemeine Chemie of Ostwald, the father of physical chemistry, was finally achieved. Nevertheless, reading Lewis' paper shows that he anticipated the ideas that underlied the physical organic school18, 20, 23 of Ingold and the resonance concept18, 24 expounded by Pauling. Indeed, Pauling himself dedicated his monograph25 to Lewis, thereby expressing the link and influence of Lewis' work on his.…”

“…The same applies to the metallic bond, where alloys (e.g., NaPb 2 ) show both “metallic” and ionic behaviors under different conditions. Here, Lewis speaks about electronic tautomerism (“tautomerism between polar and no‐polar …”), which may be thought of as the precursor of “resonance theory” employed by Pauling as a centerpiece of his intellectual construct 18, 24…”

“…Within this idea, Lewis discusses the notion of tautomerism as electronic phenomenon: “But we must assume… that these forms represent two limiting types, and that the individual molecules range all the way from one limit to the other”; this idea is reiterated near the end of the article when Lewis uses it to discuss the color of compounds because of the oscillation of “loose” electrons between extreme situations in the molecule. In an altered dress, the idea will become the mesomersim theory of Ingold 18. In the same discussion, Lewis considers intermediate cases in between the extremes—this is a seminal notion of the resonance theory 24.…”

“…Thus, although the final dress of the chemical bond has a physics' touch, with the exception of Thomson, who was avidly interested in chemistry,9 physicists were relatively late comers to theorize an effective chemical bonding mechanism. In this sense, it is noteworthy to find that in 1923, good 7 years after Lewis' publication, Born writes to Einstein about his perplexing attempts to understand the “homeoplar bonding forces” as those holding H 2 , and adds: “Unfortunately, every attempt to clarify the concept fails.”17 Yes, Lewis did not try to understand the “forces”; instead, he let himself be guided by his chemical overview to hypothesize the pairing as a quantized unit of bonding, which gave the clue to the nature of the atomic combination 18…”