this post was submitted on 09 Jun 2025
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Science Memes

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[–] [email protected] 5 points 20 hours ago

TIL chemists clearly got confused by D(ex)/S(in) and R(ight)/L(eft).

[–] [email protected] 21 points 1 day ago (2 children)

I’m not smart enough to know this.

[–] [email protected] 29 points 1 day ago

It's the title of the post: Enantiomer an identical chemical structure but mirrored. Think of how your hands are left and right. They're identical in their structure, but are mirrored. Molecules can have the same thing and were denoted by L and D (but now use + and -)

[–] [email protected] 17 points 1 day ago* (last edited 1 day ago) (1 children)

Some molecules have a rotation that is centered on a chiral carbon atom and is named by the way the other atoms of the molecule rotate. There are some rules to it, but L is levorotatory and means it rotates to the left or counter-clockwise. D is dextrorotatory and spins to the right, or clockwise.

Edit: spelling errors lol

[–] [email protected] 3 points 1 day ago (2 children)

These terms can describe any molecule, btw, doesn't have to contain carbon

[–] [email protected] 4 points 1 day ago* (last edited 1 day ago) (1 children)

Not any molecule, it’s gotta be able to have stereoisomers in the first place. There’s no R or S water for example. D/L notation is for biology.

[–] [email protected] 4 points 1 day ago (1 children)

Well yes, it does have to have chirality, I just meant it doesn't have to contain any specific elements.

I'm definitely no expert, but isn't the D/L notation used in all of chemistry? Sometimes it's written Δ/Λ, but that's the same thing. Doesn't it just describe a molecule's geometry in a different way from R/S?

[–] [email protected] 1 points 16 hours ago* (last edited 16 hours ago)

D/L refers to the entire molecule and how it polarizes light whereas R/S looks at every chiral center and has a priority system to assign. I’ve only really seen D/L in biochemistry, regular chemistry is using R/S notation. D/L is the older less precise notation. R/S is much more specific and isn’t related to polarization of light.

[–] [email protected] 3 points 1 day ago

Fair! I've only taken organic chemistry so far, so that's what I remembered

[–] [email protected] 18 points 1 day ago (1 children)

Chirality, Motherfucker! Do you have it?

[–] [email protected] 10 points 1 day ago

Say racemic. Say racemic again motherfucker!

[–] [email protected] 8 points 1 day ago (2 children)
[–] [email protected] 13 points 23 hours ago

Because the prefixes for optical rotation are dextro and levo :)

[–] [email protected] 2 points 23 hours ago

because the meme was made by a chemist and not a physicist

[–] [email protected] 4 points 1 day ago (1 children)

Ooh, do Harry S. Truman vs Harry R. Truman next!