Talk:Cis–trans isomerism

message: If trans isomers line up better than cis isomers, wouldn't their density be greater rather than lower? -- postglock 08:52, 17 September 2005 (UTC)
replies: text: I would agree; that's what I came to this page to check on.  This is borne out by looking at the density values for maleic and fumaric acid. - R.
Ok, well I changed the aricle to reflect this hypothesis that R. and I share, and added a unverified header... If anyone could help that would be great. Thanks! -postglock 09:32, 31 March 2006 (UTC)
thread_title:  trans isomers and density 

message: I have simply looked up some boiling points for cis and trans isomers of some alkenes at: http://www.chemicalland21.com/info/Alkene%20Compound%20Boiling%20Points.htm I noticed that for 2-Pentene, 3-pentadiene, 2-Hexene, and 1,3,5-Hexatriene the cis diastereomer had a higher boiling point opposite of what is stated in wiki. I think that the content concerning general trends should be eliminated and replaced with specific and sited examples since the difference between the two isomers is very specific to the molecules in question. 
trans-2-Pentene 36, cis-2-Pentene 37
1,trans-3-pentadiene 42, 1,cis-3-pentadiene 44
 
cis-3-Hexene 66, trans-3-Hexene 67
trans-2-Hexene 68, cis-2-Hexene 69
 
trans-1,3,5-Hexatriene 78, cis-1,3,5-Hexatriene 79
 
4-Methyl-cis-2-hexene 87, 4-Methyl-trans-2-hexene 88
-M_stone 16:02, 7 May 2006
: Makes good sense to me. DMacks 15:39, 8 May 2006 (UTC)
thread_title:  trends cis-trans? 

message: What is the correct form of E/Z notation?  The article shows roman, boldface roman, italic, and parenthesised italic.  Let's get this right! —The preceding unsigned comment was added by 128.250.204.118 (talk) 08:17, 20 January 2007 (UTC)
replies: text: It would seem from the IUPAC's recommendation that it should be (E)-but-2-ene -- parenthesized italic (see Enclosing marks and Italicization) IMacWin95 21:07, 21 January 2007 (UTC)
thread_title:  Form of E/Z notation 

message: The page states relatively early on that "the term "geometric isomerism" is an obsolete synonym of "cis-trans isomerism" and its use is strongly discouraged." If the usage is discouraged, then I think that this page should be moved to cis-trans isomerism and geometric isomerism should redirect, not the other way around... IMacWin95 20:56, 21 January 2007 (UTC)
replies: text: Support, but above message is 4 months old. Dunno if I should just do the move then. Ohwell32 22:06, 14 May 2007 (UTC)

text: The move to Cis-trans isomerism was done 4 years ago, on 19 May 2007 according to the revisio history. Please leave the title alone now. Dirac66 (talk) 15:27, 31 May 2011 (UTC)
thread_title:  Move? 

message: I would like to ask that the image of cisplatin and transplatin be redrawn. It was drawn in 2011 as a vector image to update the raster image :File:Cisplatin and transplatin.gif which I had drawn in 2009 (and which will soon be deleted from Wikipedia as it is no longer used in any article). The problem here is that the vector version does not conform to the usual chemistry conventions for showing the spatial geometry of the molecule, since the four ligands are in a square implying a planar diagram, but the bonds are shown as wedges and dotted lines implying a 3-dimensional diagram. So the vector image should be redrawn, but I do not have software to draw vector images, so I would like that the image be  redrawn with the four ligands in a rectangle as in my diagram, and also as in the article on cisplatin. Dirac66 (talk) 20:14, 3 August 2013 (UTC)
thread_title:  Redraw image of cisplatin and transplatin  

message: Last sentence of first paragraph: Cis and trans descriptors cannot be used in open-chain molecules, where syn and anti are used instead. I do not understand what this is supposed to mean, since all of our examples are in fact open-chain molecules except for the one pair of dichlorocyclohexanes. Can someone fix this sentence, or should it be deleted? Dirac66 (talk) 00:18, 8 February 2014 (UTC)
replies: text: The missing detail was the difference of whether it was an alkene (or other similarly-rigid form). I think it's simply supposed to be stating the logical opposite or alternative to what is explicitly included in the earlier sentences (geometrically fixed cases, such as rings and alkenes). I adjusted the wording, with link to the aspect of variable geometry. DMacks (talk) 12:18, 8 February 2014 (UTC)
replies: text: Thanks. I have added a missing not to your edit. The sentence is much clearer now. Dirac66 (talk) 00:03, 9 February 2014 (UTC)
replies: text: *blush* good catch. DMacks (talk) 04:01, 9 February 2014 (UTC)
thread_title:  Open-chain molecules 

message: I removed erroneous italics. While they are commonly italicized, this is a misunderstanding. "Cis" and "trans" are English words; they are only italicized as part of a chemical name. See The ACS Style Guide, 3rd ed., pp.145, 235. ~ Lhynard (talk) 21:13, 12 December 2014 (UTC)
thread_title:  Italics Comment Fixing style/layout errors 

message: I propose that the article's second sentence be made more clear.  It states:[Cis/trans isomerism] is not to be confused with E/Z isomerism, which is an absolute stereochemical description, and only to be used with alkenes.
Does this mean that Cis/trans should only be used with alkenes, or that E/Z is only to be used with alkenes?
Christopher.ursich (talk) 17:03, 23 April 2015 (UTC)
replies: text: Good question. A related question is what of type of molecule is excluded, since the section E/Z notation shows that halosubstituted alkenes are in fact included. So I checked an authority: Eliel and Wilen Stereochemistry of Organic Compounds (John Wiley 1994), p.1197. Their glossary item for E, Z ends with the sentence: E and Z should not be used for substituted cycloalkanes. So I suggest the article say that E/Z notation should only be used for substituted open-chain alkenes and not for substituted cycloalkanes, possibly using Eliel and Wilen as a reference. Dirac66 (talk) 18:32, 23 April 2015 (UTC)
thread_title:  Re-word comparison to E/Z isomerism? 

message: Is there a word for the process of converting cis to trans?  I thought it should be transification, but I don't see much regarding that.  More specific, the way too common case of making trans fats as a side effect of hydrogenation. Gah4 (talk) 14:05, 30 October 2018 (UTC)
replies: text: Isomerization is the general conversion of one isomer to another. So "cis–trans isomerization" is the interconversion between cis and trans. DMacks (talk) 15:42, 30 October 2018 (UTC)
replies: text: An alternate form is "cis–to–trans isomerization". Dirac66 (talk) 17:30, 30 October 2018 (UTC)
replies: text: I was trying to find a nice short word for it.  It seems that transesterification is a word for that one, but not transification for this one.  Thanks all. Gah4 (talk) 02:20, 31 October 2018 (UTC)
thread_title:  transification 

message: It seems to me that the recent change to the short description is too short. It seems to include all isomers, which misses the whole point. Gah4 (talk) 22:05, 10 August 2021 (UTC)
thread_title:  short description 

message: According to various sources I've looked at, including http://www.chem.ucalgary.ca/courses/350/Carey5th/Ch07/ch7-1.html (which is referenced in Conformational_isomerism), configurational isomers refer to isomers where "interconversion necessarily involves breaking and reforming of chemical bonds". Thus, as I understand, configurational isomers are a subtype of stereoisomers that include both cis-trans (geometric) isomers and enantiomers, since the latter also requires the breaking of chemical bonds to interconvert. Thus, would it be right to say that cis-trans isomers are a subtype of configurational isomers (instead of implying that they are the same as configurational isomers, as mentioned at the beginning of the article)? MosrodTalk 12:31, 16 August 2023 (UTC)
thread_title:  Cis-trans isomers as a subtype of configurational isomers?