Talk:Isomer

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1 Question: Isomer Named Incorrectly?
2 Formula
3 older entries
4 Tautomerism
5 Question
6 Question: structures vs. structural formulas
7 Isomerization devices
8 Has this page been hacked?
9 Chemical isomers vs. Nuclear isomers
10 where did you guys get your info
11 Template
12 valence isomer

[edit] Question: Isomer Named Incorrectly?

Is it just me, or does the article incorectly label isomer number III (3) in the graphic-drawing as isopropanol, which is an alcohol, whereas the drawing is of an isomer that is clearly NOT an alcohol - it is an ester. I need to brush up on my IUPAC naming, but it seems that CH3-CH2-O-CH3 would be something like methyl-ethyl-ester, which I'm not sure is a stable molecule. Just looking at it, it might spontaneously dehydrogenate (CH3CH2-O-CH3 --> CH3CH2-COH + H2)to form the relatively stable aldehyde - propanal(CH3-CH2-COH), although I'm purely spectulating here. My main point/question is: isn't number III an ester, not an alcohol (specifically not isopropyl alcohol) ? And if I'm right - what is it, and what of my speculation concerning methyl-ethyl-ester (if that is indeed the proper name)? Spiral5800 (talk) 13:04, 15 January 2008 (UTC)

It calls III methoxyethane, which is correct. --Itub (talk) 09:54, 17 January 2008 (UTC)

[edit] Formula

Is there a mathematical formula for the number of constitutional isomers for in the nth element of, for example, the alkane series?

Yes. I believe there is one for the Alkane series. However, this page is speaking about a more general understanding of what an isomer is, and the formula and specific details of the alkane series is better kept with the alkane series. Glooper—Preceding unsigned comment added by 220.233.184.203 (talk • contribs)

[edit] older entries

Does the definition of "isomerism" require "the same kinds of bonds between atoms"? I would have said that, say, benzene and prismane are isomers. And is it true that "isomers typically share similar if not identical properties in most chemical contexts"? In fact the examples given in the history section seem to belie both of these claims.

Josh Cherry 22:18, 13 Oct 2003 (UTC)

I wrote both those statements and I definitely wasn't thinking of prismane, which does seem to disprove the rule. On the other hand, I think a qualifier like "typically" or "generally" covers a multiple of ills. Since you pulled the example of prismane out of the air, I suspect you know more chemistry than me. If prismane is one of a relatively narrow category of exceptions (I don't know), then to me I think "typically" still cuts the mustard. I think the priority should be to convey information and not to construct all inclusive definitions. In other words, if rules of thumb exist, I think we should tell people. I arrived at "the same kinds of bonds between atoms" by thinking of a simple ketone or alcohol or halagonated alkane. I couldn't think of an isomer of one of those where you wouldn't still have a "C" double-bonded to "O", then I thought of the electron shell filling principle, and from there I jumped to my rule of thumb. But if you give a couple not too bizarre examples besides prismane, you'll convince me that I was mentally impaired. My motive in concocting this rule-of-thumb statement about isomers was my intuition that a reader who knows even less chemistry than I is likely to assume that there's no limit to the number of ways that a given set of atoms can bond to form a stable molecule--such that isomers (defined only as sharing the same chemical forumla) are unlikely to be more than trivially related--whereas actually something closer to the reverse is true. 168... 00:27, 14 Oct 2003 (UTC)

I don't think prismane/benzene is especially bizarre. Here are a few other isomer pairs to consider:

Cyclohexane and any acyclic hexene
Any ketone and its enol tautomer
Lactic acid and glyceraldehyde
H2C=C=CH2 and methyl acetylene
Some organic sulfate and some sulfide isomer with the oxygens put into hydroxyl groups or something

Josh Cherry 01:44, 14 Oct 2003 (UTC)

O.K.. I can't remember o-chem but I think I recognize when I see it. I just weakened the intro generalizations. Does that work for you? I think one of your examples above with a figure would be good to add somewhere below the intial one to illustrate how the intro generalizations do not always apply.168... 03:25, 14 Oct 2003 (UTC)

Just a minor point, the images would be better if they were enlarged somewhat. The lettering is a bit hard on the eyes and somewhat hard to decipher.

Cudos!

-Zidel

There appear to be at least one more type of isomers; nuclear-spin isomers, as in the para and ortho isomers of water (http://www.sciencemag.org/cgi/content/long/296/5577/2363, subscription required). I don't know enough about the subject to know where in the classification mentioned this would fit in (I'd guess another box beside structural isomers and stereoisomers), or if there are more types of isomers, so I think the article needs the attention of someone well versed in chemistry and particle physics to complete it. W 10:46, 24 April 2006 (UTC)

[edit] Tautomerism

Where does this fit in? Presumably under constitutional(structural) isomerism.I realise there is a link, but should it be linked to from this page? --Copperman 15:51, 29 May 2006 (UTC)

[edit] Question

Should a discussion about meso compunds not be mentioned?

[edit] Question: structures vs. structural formulas

Should isomers be defined as having different structural formulas or different structures? A minority of books claim it to be the former, while the majority seem to say that it is the latter and that stereoisomers are considered to have the same structural formula

[edit] Isomerization devices

I work in law enforcement and am reviewing the state statutes reference drug paraphernalia. I've come to notice most state statutes include "Isomerization devices" under the drug paraphernalia code. Could someone please discuss Isomerization devices as used specifically to increase the potency of species of plants.

Thank you, Anne

[edit] Has this page been hacked?

The illustration at the top contains NO "C" (Carbon) atoms, yet the descriptions clearly refer to an Oxygen atom attached to a Carbon atom. I'm no chemist but played one in college. I don't know enough to fix this, but I do believe someone qualified needs to take a peek.

Keith Adney

64.86.28.237 15:35, 25 March 2007 (UTC)

No, it has not been hacked and the illustration is correct. Carbon is present in ALL organic molecules. By convention, carbon atoms are not explicitly indicated by a letter, the way oxygen or hydrogen would be in molecular structure drawings. The carbon atoms are at the intersections or vertices of the straight lines used in drawing the chemical structure. Pzavon 16:00, 25 March 2007 (UTC)

[edit] Chemical isomers vs. Nuclear isomers

I believe this article should be renamed "Chemical Isomers". A search for Isomers should redirect here, but the page should be called Chemical Isomers.

I know it sounds pedantic, but it's just common sense I think. What does everybody else think? Glooper—Preceding unsigned comment added by 220.233.184.203 (talk • contribs)

[edit] where did you guys get your info

Have you ever consulted a organic chemistry textbook. This page has so many errors that if needs to be totally rewritten.

To wit:

(1) Conformers are technically diastereomers, but are rarely considered so.

(2) Diastereomers consist of other isomers than conformers and cis/trans isomers. What about glucose and galactose? They are diastereomers.

(3) Biological systems typically discriminate between enantiomers. Other stereoisomers (i.e., diastereomers) are different chemical compounds. Get this straight.

(4) Xanthines are a very obscure example of isomers with different properties. Choose a better example.

(5) Why are cis-trans isomers important in food chemistry. I don't see a connection. They are really important in organic chemistry, which isn't mentioned.

(6) Some tautomers can be separated.

(7) The only type of stereoisomer that rotates polarized light is an enantiomer.

(8) Topoisomers are incredibly important in organic chemistry, especially in catalysis. Consider BINAP.

(9) Etc., etc., etc., ad nauseum.

Are you authors even chemists? PLEASE, PLEASE, PLEASE consult a textbook and get this stuff correct. It is really simple.

Have added an unreferenced template. I would have though this one would at least have a references section. Richard001 03:57, 19 August 2007 (UTC)

[edit] Template

A template linking together the different types of isomerism would be handy. Any chemistry editors willing to make one? Richard001 (talk • contribs) 03:57:14, August 19, 2007 (UTC).