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Offline dillydoo

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Nomenclature?
« on: September 16, 2015, 10:53:30 AM »
I guess you might understand by now that I'm really new to chemistry. I wish I could understand why everything is named the way it is but for me it all just seems to jumble/intersect. I think I might have a (moderate) case of dyscalculia (but no dyslexia) because I can't seem to quantify, understand clearly or put the defining factors for the 2-dimensional (binary) nomenclature in a good, organized hierarchy/function/table fluently enough without frustrating myself. I'll try to put down my thoughts in the order they come here...

Take CH3OH;
From my understanding, when breaking down the elements it's:
(1 Carbon + 1 Hydrogen)3 + (1 Oxygen + 1 Hydrogen)
And in my head, it would be called Tricarbonhydrate (mon-)oxy(gen)hydride - if you can follow my thoughts.

And then starts the transitions in my head...

Variation #1:Tricarbohydrate Monohydroxide.
The rule seems to be, with the anion in the cation compound; Even without oxygen, it's "oxidated" one more than -ite. Thus calling the hydrogen hydrate. I suppose this is the same with other oxidated anions, for example -ide for it's original state etc. Carbon also loses n to the vowel o for some reason. And then there's the original exception in the nomenclature rules for oxygen. It's read after the anion in the anion compound when it's written OH. And anyway, how would I know if there are more exceptions like this out there if I didn't do my research? It's frustrating without set rules...

Variation #2: Tricarbonate or Trihydrocarbonate or Trihydrate Monohydrate?!
Taking my next step in the spirit of oxidation nomenclature but with no exceptions and much thrashing about, I end up at aforementioned... if I were to type those out in formulas per this particular logic lacking the exception-variable it'd be: CH3OH, HC3(OH), or even H3(OH). Except they're just blasphemy; The first one doesn't match the formula-name and it's apparently O3C(OH), the second one doesn't work out due to a number of factors and the third one just turned into something else entirely.

...and then: MeOH?! Methanol, Methyl Hydrate, Methyl Hydroxide?!
All of a sudden, wham bam, kazam. Where's the logics? How do I put two and two together in an equation with a bunch of unknown exceptions? Has it turned into a function with a pre-set table of variables? Because, sure, everyday you create new compounds and they all have names too and you suddenly need to learn them as a language of names instead of mathematics. Meaning, it's all just pure memorization apart from the basic rules and at the end of it, no control at all?

Returning to exceptions: H3C(OH) and O3C(OH)
Why is it suddenly called Tricarbonic (mono)hydrate(hydroxide)? Due to another exception? So now we have two exceptions, acidic when you add a hydrogen at the start of the reaction formula... But what happens if you use none of these two for oxidation? I'm so lost in the nomenclature apart from the simple binary prefixes and suffixes...

Are there any simple lists of what exceptions there are in the nomenclature?

Offline Corribus

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Re: Nomenclature?
« Reply #1 on: September 16, 2015, 11:52:05 AM »
The purpose of standardized chemical nomenclature is to allow for unambiguous identification of chemicals in formal scientific literature. IUPAC is responsible for most of the standardized chemical nomenclature in use today. In the overwhelming majority of cases, IUPAC nomenclature is utilized in professional science publications, although there are many cases where common names of chemicals are used and widely understood.

There's really nothing else but to just learn the rules, which are in most cases fairly simple. The rules for inorganic and organic chemicals are somewhat different. For the latter, it starts with identification of the parent hydrocarbon, and then clearly identifying important functional groups or branches. In the case of methanol, since you brought it up, the parent hydrocarbon is methane. The "ane" here refers to the saturated hydrocarbon nature and the "meth" is derived from Greek, relating to wine - methanol was originally produced by distillates of wood (which is why methanol is also sometimes called wood alcohol). Most of the prefixes you come across have Greek roots, either numerical (for hydrocarbons larger than four) or from chemicals known in before modern science (in the case of methanol). The "ol" suffix should be fairly self-explanatory.

Bear in mind that while "methanol" may be IUPAC accepted term, methyl alcohol is also perfectly acceptable and widely used. In many cases, non-systematic names are far preferred. Few would refer to caffeine as "3,7-dihydro-1,3,7-trimethyl-1H-purine-2,6-dione", even in the professional literature. But for less common chemicals, having a set of rules for unambiguous identification of chemicals is critical.

While it may be possible to refer to methanol chemical as carbon trihydride hydrogen monoxide, and indeed it may make more logical sense, as a nomenclature system such a scheme would fail utterly. For even slightly larger molecules, the chemical names would become ridiculously cumbersome and impossible to recognize. Note that such cumbersome language has in the past been used in a humorous way (https://en.wikipedia.org/wiki/Dihydrogen_monoxide_hoax).

Wikipedia has a half decent entry on organic nomenclature, and there are oodles of other sources on the web that can teach you the rules. Any intro level organic chemistry textbook will also include a full treatment of the subject.  Inorganic nomenclature is handled in similar fashion, and in fact is more straightforward generally. Then, inorganic molecules tend not to be nearly as large. :)

https://en.wikipedia.org/wiki/IUPAC_nomenclature_of_organic_chemistry
« Last Edit: September 16, 2015, 12:11:56 PM by Corribus »
What men are poets who can speak of Jupiter if he were like a man, but if he is an immense spinning sphere of methane and ammonia must be silent?  - Richard P. Feynman

Offline Dan

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Re: Nomenclature?
« Reply #2 on: September 16, 2015, 12:00:36 PM »
Take CH3OH;
From my understanding, when breaking down the elements it's:
(1 Carbon + 1 Hydrogen)3 + (1 Oxygen + 1 Hydrogen)
And in my head, it would be called Tricarbonhydrate (mon-)oxy(gen)hydride - if you can follow my thoughts.

I struggle to follow your logic. "Hydrate" means +water, not +H. I think you are confusing hydrate and hydride. Tricarbon implies C3.

Hydroxycarbon trihydride is what I think the systematic name would be using inorganic nomenclature (but that's not my area of expertise, so I might be wrong).

The name "methanol" is the systematic name according to IUPAC nomenclature of organic chemistry. Inorganic and organic nomenclature are related but different languages. They are both logical, it is not arbitrary memorisation, a computer program can determine the IUPAC name of novel molecules using the rules of nomenclature, but you do need to learn the rules in order to name compounds.
My research: Google Scholar and Researchgate

Offline dillydoo

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Re: Nomenclature?
« Reply #3 on: September 16, 2015, 12:44:45 PM »
The purpose of standardized chemical nomenclature is to allow for unambiguous identification of chemicals in formal scientific literature. IUPAC is responsible for most of the standardized chemical nomenclature in use today. In the overwhelming majority of cases, IUPAC nomenclature is utilized in professional science publications, although there are many cases where common names of chemicals are used and widely understood.

There's really nothing else but to just learn the rules, which are in most cases fairly simple. The rules for inorganic and organic chemicals are somewhat different. For the latter, it starts with identification of the parent hydrocarbon, and then clearly identifying important functional groups or branches. In the case of methanol, since you brought it up, the parent hydrocarbon is methane. The "ane" here refers to the saturated hydrocarbon nature and the "meth" is derived from Greek, relating to wine - methanol was originally produced by distillates of wood (which is why methanol is also sometimes called wood alcohol). Most of the prefixes you come across have Greek roots, either numerical (for hydrocarbons larger than four) or from chemicals known in before modern science (in the case of methanol). The "ol" suffix should be fairly self-explanatory.

Bear in mind that while "methanol" may be IUPAC accepted term, methyl alcohol is also perfectly acceptable and widely used. In many cases, non-systematic names are far preferred. Few would refer to caffeine as "3,7-dihydro-1,3,7-trimethyl-1H-purine-2,6-dione", even in the professional literature. But for less common chemicals, having a set of rules for unambiguous identification of chemicals is critical.

While it may be possible to refer to methanol chemical as carbon trihydride hydrogen monoxide, and indeed it may make more logical sense, as a nomenclature system such a scheme would fail utterly. For even slightly larger molecules, the chemical names would become ridiculously cumbersome and impossible to recognize. Note that such cumbersome language has in the past been used in a humorous way (https://en.wikipedia.org/wiki/Dihydrogen_monoxide_hoax).

Wikipedia has a half decent entry on organic nomenclature, and there are oodles of other sources on the web that can teach you the rules. Any intro level organic chemistry textbook will also include a full treatment of the subject.  Inorganic nomenclature is handled in similar fashion, and in fact is more straightforward generally. Then, inorganic molecules tend not to be nearly as large. :)

https://en.wikipedia.org/wiki/IUPAC_nomenclature_of_organic_chemistry

Thank you for the overview and even the humor! I think I see what you mean regarding the problematics of keeping the nomenclature at it's purest form in logics, there are certain similarities with that to assembly code versus higher levels of coding languages like c or c++. When there are suddenly more dimensions introduced, especially for molecules, I can just picture what a disaster it'd be.

However, it does help me understand the basics, being able to break the elements down into this structure (when it comes to simpler formulas at least), like which you pointed out; "carbon trihydride hydrogen monoxide" from CH3OH. I called it something else entirely, which seems a little silly when I look back. I just realized that you don't actually put the prefixes and suffixes infront/behind a compound but you check the cation and anion separately if there are no brackets before the value is given... Which I think means (repeating this for the sake of memorizing) CH3 is not an actual compound and two separate ions in a bond so you only count the atom/ion that came before the number... I feel completely embarrassed haha!

I will just have to research the standardization as presented to me. I think the fact that I was sick and missed the three lessons where my class went through the nomenclature is the biggest factor in my confusion, thanks!

Offline dillydoo

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Re: Nomenclature?
« Reply #4 on: September 16, 2015, 12:48:57 PM »
Take CH3OH;
From my understanding, when breaking down the elements it's:
(1 Carbon + 1 Hydrogen)3 + (1 Oxygen + 1 Hydrogen)
And in my head, it would be called Tricarbonhydrate (mon-)oxy(gen)hydride - if you can follow my thoughts.

I struggle to follow your logic. "Hydrate" means +water, not +H. I think you are confusing hydrate and hydride. Tricarbon implies C3.

Hydroxycarbon trihydride is what I think the systematic name would be using inorganic nomenclature (but that's not my area of expertise, so I might be wrong).

The name "methanol" is the systematic name according to IUPAC nomenclature of organic chemistry. Inorganic and organic nomenclature are related but different languages. They are both logical, it is not arbitrary memorisation, a computer program can determine the IUPAC name of novel molecules using the rules of nomenclature, but you do need to learn the rules in order to name compounds.

Thanks for pointing it out! Yeah, I'm still pretty confused on the subject. Hydride was when the oxidation number was 0, right? Then hydrate is one more than hydrite? I think I confused myself from the beginning to the end because I forgot to check for brackets.

But like you both mentioned - regarding the IUPAC standardization, I may as well just do my own homework and research it better. I'm trying to catch up with my class, because I missed a few lessons. Thanks!

Offline dillydoo

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Re: Nomenclature?
« Reply #5 on: September 16, 2015, 12:56:39 PM »
I just realized another thing I need to practice. Learning to see which ions are actually cations and anions in a larger compound chain.

Offline Arkcon

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Re: Nomenclature?
« Reply #6 on: September 16, 2015, 05:07:16 PM »
We don't use IUPAC names for organic compounds, they have a different nomenclature.  Its just that simple.  P.S. no one ever refers to H2O as 'dihydrogen mono-oxide'.  Its always water.
Hey, I'm not judging.  I just like to shoot straight.  I'm a man of science.

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