Talk:Chemical polarity

I would like to ask is that all element molecule is count as non-polar? As O3(Ozone) is polar, I think it is not correct for all element Ax is non-polar, it should be change to Most element molecule Heichai88 07:18, 8 October 2007 (UTC)Reply

="Molecules with an O at one end"

Water does not have an O at the end! Who wrote that and dares to call themselves a chemist?! 217.205.231.117 14:09, 5 November 2007 (UTC)Reply

Where are the sources for this article? —Preceding unsigned comment added by 76.202.161.195 (talk) 20:41, 7 November 2007 (UTC)Reply

"However, methane is considered non-polar because the carbon shares the hydrogen molecules uniformally." - surely hydrogen atoms...? (although I dropped chemistry aged 13 some decades ago, so I might be wrong) Saxobob (talk) 21:49, 2 January 2008 (UTC)Reply

"A molecule is composed of one or more chemical bonds (covalent bonds) between molecular orbitals of different atoms. " Should be "A molecule is composed of one or more chemical bonds (covalent bonds) between atomic orbitals of different atoms." Even that is not perfect, but it's an improvement upon what is currently there. Atoms do not have "molecular" orbitals. I've never submitted a correction suggestion before, so I apologize if there's an error in my protocol. Thank you C2v (talk) 05:18, 10 May 2009 (UTC)Reply

The grammar in the intro is really weird in some places....

--Heero Kirashami (talk) 01:36, 6 November 2008 (UTC)Reply

Who made this? Is it acccurate? D guz (talk) 18:40, 6 February 2011 (UTC)Reply

FYI, the ACS Style Guide specifically states that the "nonpolar" should not be hyphenated, as it is throughout this article. — Preceding unsigned comment added by Lhynard (talk • contribs) 20:28, 26 April 2011 (UTC)Reply

The pictures seem to imply that the thing about polarity is the shape, or perhaps asymmetry, of a molecule's electric field.

The explanation of it being because of the unequal sharing of electrons seems to me to be misleading. It is the shape of the electrons' orbits, I think, and not what is written.

Thus, one can see that the non-polar molecules are symmetric and the polar molecules are non symmetric, as regards the orbits of their electrons.

Shouldn't the entry be rewritten? — Preceding unsigned comment added by 31.210.181.37 (talk) 15:18, 12 April 2012 (UTC)Reply

The article puts the boundary between covalent and ionic bonds as being a DEN (difference in electronegativity) of 2.0 and then goes on to say that it is 1.7 on the Pauling scale. I would like to see an explanation as to why the higher value is quoted and where it comes from.

It contradicts the pages below both quote the 1.7 figure:

https://en.wikipedia.org/wiki/Chemical_bond#Ionic_bond https://en.wikipedia.org/wiki/Ionic_bonding

Jim23mac (talk) 10:58, 11 March 2015 (UTC)Reply

Good point. The boundary is of course arbitrary in that it does not correspond to any observable phenomenon. And I vaguely remember that there are conflicting sources with some books saying 1.7 and some 2.0. The 1.7 is referenced to Pauling's book, so for now I will put a citation needed tag on the 2.0. If someone can track down a source for 2.0, then we can adopt a neutral point of view (WP:NPOV) and mention that there are conflicting sources. If no one finds a source, then after a while we can revise the 2.0 to 1.7. Dirac66 (talk) 01:56, 15 March 2015 (UTC)Reply

If everyone agrees that the cutoff is arbitrary (which it most certainly is), why should the article cite a cutoff anyway? At the very least, it should state a range of possible cutoff values. Furthermore, the article doesn't even agree with the references that are included. I am going to change things to make it a bit more vague, which is appropriate in this case. JCMPC (talk) 12:17, 23 February 2016 (UTC)Reply

"When comparing a polar and nonpolar molecule with similar molar masses, the polar molecule in general has a higher boiling point, because the dipole–dipole interaction between polar molecules results in stronger intermolecular attractions."

Wouldn't that imply LOWER boiling point? 172.243.190.237 (talk) 09:54, 19 August 2016 (UTC)Reply

No, higher is correct. Intermolecular forces hold the molecules together in the liquid state, where the molecules are close together. In the gas state the molecules are far apart and intermolecular forces are not important. So polar molecules exert stronger attractions on each other in the liquid state, and it requires a HIGHER temperature to provide enough thermal energy to separate the molecules. Dirac66 (talk) 17:16, 19 August 2016 (UTC)Reply

I think however that you may have been confused because the sentence you quoted was in the section on Nonpolar molecules. Since it actually refers to polar molecules, I have now moved it to the section on Polar molecules where it belongs, and added as an example the comparison of water with methane. Dirac66 (talk) 20:35, 19 August 2016 (UTC)Reply

Hello fellow Wikipedians,

I have just modified one external link on Chemical polarity. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:

• Added archive https://web.archive.org/web/20150109175856/http://dwb.unl.edu:80/Teacher/NSF/C06/C06Links/www.uis.edu/7Etrammell/organic/introduction/polarity.htm to http://dwb.unl.edu/Teacher/NSF/C06/C06Links/www.uis.edu/7Etrammell/organic/introduction/polarity.htm

When you have finished reviewing my changes, please set the checked parameter below to true or failed to let others know (documentation at {{Sourcecheck}}).

This message was posted before February 2018. After February 2018, "External links modified" talk page sections are no longer generated or monitored by InternetArchiveBot. No special action is required regarding these talk page notices, other than regular verification using the archive tool instructions below. Editors have permission to delete these "External links modified" talk page sections if they want to de-clutter talk pages, but see the RfC before doing mass systematic removals. This message is updated dynamically through the template {{source check}} (last update: 5 June 2024).

• If you have discovered URLs which were erroneously considered dead by the bot, you can report them with this tool.
• If you found an error with any archives or the URLs themselves, you can fix them with this tool.

Cheers.—InternetArchiveBot (Report bug) 03:46, 21 November 2016 (UTC)Reply

  A discussion is taking place to address the redirect Fractional charge. The discussion will occur at Wikipedia:Redirects for discussion/Log/2021 February 3#Fractional charge until a consensus is reached, and readers of this page are welcome to contribute to the discussion. ComplexRational (talk) 15:06, 3 February 2021 (UTC)Reply

77.212.171.42 (talk) 18:03, 14 June 2011 (UTC)Reply

Read the next sentence.--80.56.228.252 (talk) 16:03, 15 June 2011 (UTC)Reply

I was wondering if I could change the explanation for how (and why) many introductory chemistry texts draw dipole moments backwards (with a cross to denote the positive side of the dipole moment)? I realize that there is good reason to follow the conventions set by physicists, but I don't believe that the chemists' conventions should be ignored. Here are my reasons:

1. This page is in the WikiProject Chemistry and even in the Chemical bond properties category. Thus, if the page is going to yield to the conventions of only one discipline (chemistry vs. physics), it would seem reasonable to choose the chemists' convention.
2. Many introductory (and even medium level) chemistry textbooks use the "backwards crossed arrow" notation but do not imply that the direction is arbitrary. The symbol may not make sense to everyone, but it is used, and it does give very specific information. The direction 'is' defined in reference to the partial charges. I would like this page to at least mention the notation which nearly every new chemistry student is familiar with.
3. From a personal standpoint, I still prefer using the "backwards crossed arrow" notation because then my dipole moments are not mistaken for electric fields in lecture notes.

I just don't want to delete the explanation and reference of Jsd without throwing my idea and reasons out there for a while... MRDubay 23:29, 21 July 2011 (UTC) — Preceding unsigned comment added by MRDubay (talk • contribs) Reply

I am reading my Organic Chemistry textbook right now (Carey, Organic Chemistry, 8th edition). It says bond dipoles are drawn from plus to minus. The cross on the positive end of the dipole indicates a positive charge. — Preceding unsigned comment added by 99.50.93.121 (talk) 22:52, 27 September 2012 (UTC)Reply

I suggest removing or revising the last paragraph as it appears to be a summary (although not labelled as such) but is poorly written and somewhat misleading. Jim23mac (talk) 09:11, 11 March 2015 (UTC)Reply

Yes, I agree with you. This just repeats the introduction where it is better written. So I have deleted it. Dirac66 (talk) 10:46, 13 March 2015 (UTC)Reply

In this article I read that the vector is " pointing from minus to plus" and in the figure illustrating the same paragraph, it is the opposite convention. Jflm (talk) 20:48, 5 July 2017 (UTC)Reply

Minus to plus is the physics convention. Plus to minus is the chemistry convention based on the fact that electron movement causes the bond dipole. The relation between the two could be clarified. Dirac66 (talk) 20:44, 7 July 2017 (UTC)Reply

I have been reading this paragraph on the deflection of water for a while trying to figure out how to succinctly clarify it. I even read the reference by Ziaei-Moayyed and Goodman (and some other web disussion on this topic). The paper is correct in its findings, but carefully distinguishes between what is true and what might be true. So, not critical of the paper. Here is what needs fixed.

1. " ... after a stream of water is grounded, it can no longer be deflected." Not correct and not what the reference says. The true statement is that in a uniform field, neutral drops experience no force (or deflection). The typical classroom demonstration just puts some charged rod near a water faucet and one sees the stream attracted. Those are different. The water faucet is grounded and the water stream or drops actually acquire charge because it is grounded.

2. Earlier, the statement "deflection occurs because of electrically charged droplets in the stream" is sort of right but saying "droplets" presumes that the demonstration is being done after the stream has separated into droplets but sometimes it is and sometimes not. Same observation however either way.

Look, I understand the person who wrote this originally had to squeeze some subtle ideas into a small space and did manage to get the main idea across. After a few moments thought I have not done better. I might say something like this. (Keep the same reference to Ziaei-Moayyed and Goodman) - The traditional classroom demonstration showing a weak stream of water deflected by a nearby charge is often improperly offered as deminstration of the polarity of the water molecules. Careful analysis (ref) shows the deflection is largely due to charges on the fluid (or droplets) induced by the nearby charge. The polar molecules themselves only experience force due to an inhomogeneous field (same ref) which is a very much smaller force in the classroom setting and normally overwhelmed by the force on the induced charge on the liquid. Polar and nonpolar fluids are affected when such charge is acquired and the conductivity of the fluid facilitates the acquisition of such charge. -- I tried to keep it short enough so as not to detract from the primary thrust of the article, but it is important since a teacher may have a student pronounce the demonstration as wrong after reading Wikipedia. See also: [1]https://chemistry.stackexchange.com/questions/35846/is-water-stream-deflecting-in-an-electric-field-really-based-on-waters-polarity#36944 Mike (talk) 19:15, 5 February 2023 (UTC)Reply

@Mlee Thank you for taking the time to look into this in such detail. I agree that your text is an improvement. Nuretok (talk) 16:50, 10 February 2023 (UTC)Reply