cis isomer

I don’t get why cis people are so amused with the term cis. They sometimes say it in a very mocking way. It’s the proper Latin opposite of trans. Cis means “on the same side” and trans means “on the opposite side.” Trans people didn’t make this up, it appears in other places. You see it in organic chemistry, there are cis isomers with molecules on the same side of the carbon chain and trans isomers with molecules on opposite sides. The West Bank used to be called the Cisjordan, because it was on the same side of the Jordan river as Jerusalem. And conversely, what is now the nation of Jordan was called Transjordan or Transjordanian Palestine. It just goes to show that the people saying things like “SJWs use made up words” are never going to be satisfied, because it doesn’t get any more official than Latin.

Don’t Stand So Close To Me Ch 3 (Biadore) - Splatt

Thank you for all the kind feedback! Here’s chapter three. This chapter has homophobia and transphobia in it, so if that makes you uncomfortable, please be aware. Stay tuned, because there may or may not be some smut in the next chapter…

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Cis/Trans and E/Z Naming

  • Cis - same side
  • Trans - opposite side
  • E - opposite size (think eppesite side)
  • Z - same side (think zame zide)

When you name alkenes, you have to account for the isomer that you’re talking about. Cis/Trans naming is used for alkenes in chains or disubstituted alkenes like the top row of alkenes, 2-butene and 3-hexene. Cis/Trans and E/Z could be applied to these. The cis isomer is when the two hydrogens are on the same side of the double bond and the two alkyl chains are on the other. The trans isomer is when they’re switched. So going across the image above, the structures would be:

  • Trans-2-butene or (E)-2-butene
  • Cis-2-butene or (Z)-2-butene
  • Trans-3-hexene or (E)-3-hexene
  • Cis-3-hexene or (Z)-3-hexene

Once there is more than one substituent on each sp2 carbon, the cis/trans naming cannot be used. E/Z naming is essentially the same thing, however it’s based on the “weight” and “heaviness” of the substituents. The heavier the substituent, the higher it ranks. When judging how to name E/Z, the attachments on each sp2 carbons are identified, never judge across the double bond. Only compare the two substituents connected to the same carbon, as circled in the image above. The heavier one is chosen. In the second row, there is:

  • (E)-2,3-dibromo-2-butene
  • (Z)-2,3-dibromo-2-butene
  • (E)-3,4-dimethyl-3-hexene
  • (Z)-3,4,-dimethyl-3-hexene

Issues arise when the same substituent is connected to the same carbon like the first two structures in the third row. The first structure has two ethyl groups coming off the sp2 carbon and in the second one, there are two hydrogens on the sp2 carbon. This leaves it so that there can’t be isomers of the structure. Underneath, on the last row, is maleic and fumaric acid. These two are isomers of each other and are common examples of E/Z isomers. The last structure is (Z)-4-methyl-1,4-hexadiene. You’ll notice that there are two double bonds in the structure, but only one of them can be an E/Z. Since the terminal double bond has two hydrogens, it’s ineligible to be an isomer. 

(sorry for the long post, I hope this helps!!)

anonymous asked:

To the anon asking why cisgender is a term: 'cis' is just the opposite of 'trans' no matter if its related to gender or not! Cis is just latin for "on this side of" and trans is latin for "on the other side of." A good example of this is the words 'cismontane' (meaning on this side of the mountain) and 'transmontane' (meaning on the other side of the mountain. Same with cisatlantic and transatlantic. So any word with a prefix of 'trans' has a theoretical opposite starting with 'cis'!

!!

Kevin says: yeah and cis-trans isomers in chemistry! just means same side or other side of the molecule!!