Back in high school, long time and many seas away, I learned about electrons moving within organic molecules based on electromeric and inductive effect. Googling them today, I found that they are deemed obsolete by IUPAC, but still used, mainly in Russia and India.

True, today, for my limited chemistry needs, I can make do with resonance. But how did +E, -E +I and -I become obsolete? Is a mere statement of the various resonance structures enough to fully convey the information stated by describing those effects, or were they rejected for some inaccuracy?

Also, were these effects part of Chelintsev's "Marxist chemistry"? That would explain their historical and geographical extent.

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    $\begingroup$ Didn't heard earlier about electromeric, but inductive isn't obsolete, rather common in rationalising properties. $\endgroup$ – Mithoron Aug 3 '16 at 0:34

The concepts of electromeric and inductive effects are not obsolete.

Only the term "electromeric" is obsolete and has been subsumed in the terms "mesomeric effect" (+M and -M) and "resonance effect" (see iupac source). The term "isomeric effect" is still in use and I learned it not a decade ago along with "mesomeric" and "resonance".

Amusingly, your SE question is my first result in google for "Marxist chemistry". From the little I have just read in this book, Marxist chemistry had apparently more to do with refusal of the concept of resonance than anything else. So... maybe? Maybe not.

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    $\begingroup$ In the schemes describing electromeric effect, some arrows describe the movement of chemical species but standards now use arrows to describe the movement of a pair of electrons. The electromeric effect (on a scheme) is then implied. $\endgroup$ – SteffX Aug 3 '16 at 14:11
  • $\begingroup$ Are you sure @SteffX? This page shows curved arrows "symbolizing the displacement of electron pairs". I'm genuinely curious. $\endgroup$ – SCH Aug 3 '16 at 14:54
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    $\begingroup$ Sorry my comment was a bit misleading. I am not saying it was a convention but I have seen arrows from a proton to a double bond (and it actually makes sense in the context of electromeric effects). Maybe it was just a bad scheme. $\endgroup$ – SteffX Aug 3 '16 at 15:17
  • $\begingroup$ Maybe =]. Anyway thank you for your elucidations. $\endgroup$ – SCH Aug 3 '16 at 15:24
  • $\begingroup$ @S.Chevalier Chelintsev's model could not deny resonance per se, because its measurable effects were undeniable. But he was uncomfortable with the thought that electrons move from place to place without a pulling /pushing measurable force. The absence of a force jarred with materialism - the basis of "Marxist science". So he called the effects "mutual influences", to make them seem force-y. I think. In my understanding, re-wording is also the way to obsolescence for +E, -E. Chelintsev was at the forefront for <6 years and failed to muzzle critics. "Marxist chemistry" is stretching it. $\endgroup$ – nvja Aug 3 '16 at 18:35

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