0
$\begingroup$

I recently began studying chemistry, only to find out that, apparently, concepts such as “octet expansion” and Lewis structures are outdated and incorrect. And I don’t mean they’re approximations of reality, as is the case for numerous theories taught in physics, but, apparently, actually incorrect and deprecated concepts. However, commonly promoted textbooks still teach these concepts as though they are true, with no reference to them being outdated or incorrect. I find this both disappointing and disturbing, since I want to learn concepts that are actually correct. And when I purchase (expensive, recently published) textbooks, I expect to be taught correct and up-to-date concepts — especially since the people who wrote these textbooks are in an academic position to know better.

At the moment, my goal is to study both physical and organic chemistry. I was wondering if people could please recommend good textbooks in these areas that do not teach incorrect, outdated, and deprecated concepts.

$\endgroup$
3
  • 1
    $\begingroup$ All recommendations are listed in Resources for learning Chemistry. Knowing obsolete concepts is somewhat necessary. I don't know how it's these days, but a decade ago "obsolete" systems like MS-DOS and UNIX were still taught during the computer science course at the high-school, and must I say it helped a lot in understanding higher-level stuff later on. $\endgroup$
    – andselisk
    Dec 14 '19 at 10:25
  • 1
    $\begingroup$ @andselisk Hmm, I see. In that case, maybe I should stick with those "commonly recommended" textbooks. Thanks for the advice. $\endgroup$ Dec 14 '19 at 10:32
  • $\begingroup$ Lewis structures are neither incorrect nor deprecated, and commonly used with the assumption that practitioners of chemistry are aware its conceptual role and limitations. It would be very hard to read eg organic synthetic papers without using them. $\endgroup$
    – Greg
    Dec 14 '19 at 16:39
4
$\begingroup$

I disagree with the idea to forget about Lewis formulae because of their age. If you browse across the table of contents of scientific journals, however, you see Lewis formualae are widely used. From the first December issue of Organic Letters, for example is taken the following screen photo:

enter image description here

If Lewis formulae were so off and wrong, chemists would use other forms to describe molecular structures in their publications. As so often, however, it is a question about what you want to describe, and to know what limitations of the tools at disposition inheritated.
By convention (and training), for example, chemists do not read the rings in formula about nitronaphthalene (on the left) as an alternation of isolated single- and double bonds, but conceptionalize this as to depict aromatic systems. Counting electrons, for example, this is easier this way as with the Thiele ring which accentuates the delocalization of the $\pi$-electrons.*)

enter image description here

(source)

So it is better to recognize where Lewis formulae may be misleading, with some instances listed e.g., here, and some you will encounter in study, e.g. diborane

enter image description here

(source)

It equally is helpful to know that dashes in formulae, depending on convention, may represent different aspects:

enter image description here

(source)

*) In 1899, Thiele's perspective was to emphasize that benzene's molecular structure is between the two mesomeric structures expressed as Kekulé-structure and thus used the (initially dashed) cricle in the structural formula. Chemists' perspective of delocalization of $\pi$-electrons today obviously is influenced by quantum physics.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.