• sga@lemmy.world
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    2 days ago

    actually we start numbering by minimising the number of highest order addition, which is the isobutyl, if it gets same number regardless, then we try to minimise the sum of numbers, so i think it should be called

    5-(isobutyl)-5,6,6,7,8-penta-ethyl-8-methyl-decane (I am assuming hydrogen’s are present, just not represented, because that usually is the case)

    I may alo be wrong here, it has been 4 years since I have been required to do nomenclature myself

    • Hellfire103@lemmy.ca
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      1 day ago

      Ah, my chemistry department taught me the other way around. I distinctly remember the phrase “methyl-ethyl” being thrown around a bit. Additionaly, we were taught to be more specific about isomers, hence me using butan-2-yl instead of isobutyl.

      Then again, scientists often disagree strongly about things like this, so we could both be right. Also, there’s a good chance this is just the A-Level specification being weird. I left my old textbook at my student flat, though, so I won’t be able to check for a couple of weeks.

      I could also be downright wrong myself.

      As for the hydrogens, I had assumed they were not present, and that this lossane molecule is an ion with a charge of -50. This is borderline impossible to achieve in real life, of course.

      • sga@lemmy.world
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        1 day ago

        Now i remember we also had to specify what isobutyl (technically just 1 isobutyl exists (not counting stereoisomers), and other form would be tertbutyl). But giving highest priority and minimising sum were definitely something we were taught.

        I was free enough to look it up this time - IUPAC guidelines for organic chem - https://iupac.org/wp-content/uploads/2021/06/Organic-Brief-Guide-brochure_v1.1_June2021.pdf (or more generally https://iupac.org/what-we-do/nomenclature/brief-guides/)

        Section 7 ( c ) Lowest locant(s) for principal characteristic group(s)

        Although I also remember just as we completed our unit on nomenclature, all we got was “common names”, now i was supposed to know of the top of my head what a cumene is (which I think is isopropyl benzene (not going to check this one)). Same thing happened with polymers, we were taught IUPAC, and then again, “industrial names”