Talk:Coordination complex

message: I'm perplexed as to why there is no mention of the importance/function of metal complexes in hemoglobin in this article whatsoever. Could someone please expand this article in that specific area? 
Ajaxkroon 11:02, 29 March 2006 (UTC)
replies: text: I've done something about it. --Dirk Beetstra 08:40, 16 May 2006 (UTC)
thread_title: Hemoglobin

message: Non-covalent bond?  Aren't the bonds considered to be covalent since they are sharing? Olin 17:28, 31 March 2006 (UTC)
replies: text: I don't think the term applies to that, I'm not sure though. A coordinate covalent bond would be like the one between the extra H and N in NH4+, because both electrons come from the electron pair on N. Since complexes are often, if not mostly or always, composed of a central metal ion (which is positively charged), it'd be hard for that to donate electrons. They might come from the ligands though, although I'd still say there's a largely electrostatic attraction. I'd have to look it up to be sure. Jack the Stripper 14:57, 22 September 2007 (UTC)
thread_title:  Um... 

message: I am removing some ambiguous statements in the Atomic structure of coordination compounds section of the article.  Some are not untrue, but I think it is better to give real reasons (which have already been explained) instead of 'rule of thumb'-like statements.  (As an example, the reason why late transition metals tend to have lower coordination numbers, is that (for a given oxidation state) late transition metal ions are smaller than the early transition metal ions (Sc3+ is much bigger than Co3+), so less ligands tend to fit around late transition metal ions.  But, coordination is governed by overlap between orbitals (a thing also true for main group elements). --Dirk Beetstra 15:44, 16 May 2006 (UTC)
thread_title:  Statements in '''Atomic structure of coordination compounds''' 

message: I just took another look at this for the Wikipedia:WikiProject_Chemistry/Worklist, and it's certainly come a long way (it was only a "Start"), thanks a lot for adding all this content Smokefoot and Beetstra!  I wanted to ask a few questions:
*I formatted a ref and noticed after doing so that it had was the same as an external link.  Can you clarify which it is?  (Wikipedia defines refs as actually used in the writing of the article, whereas ext links are just nice pages folks might find helpful).
::No clue .. ref was there already, did not have a look .. --Dirk Beetstra 07:34, 22 May 2006 (UTC)
replies: text: The most I did was reorganising some pages, moving the info to the page where I thought it belonged, a lot of info is coming from Ligand (which does not contain any references as well ..).  The article surely needs some references, but I must confess, most of my chemistry-books are back in NL, I (re)write info that (to me) is common knowledge or logic.  I may have to have a dive into the library for some things.  --Dirk Beetstra 07:34, 22 May 2006 (UTC)
replies: text: Chelation gets quite some space in ligand (in the section denticity, it might need some attention there).  I think that it is more appropriate there, chelation is a property of a ligand, not of a complex (IMHO, it should only be noted here that complexes with chelating ligands tend to be more stable in terms of ligand dissociation).. By the way, it still lacks the thermodynamic rationale behind the concept of chelation. --Dirk Beetstra 07:34, 22 May 2006 (UTC)

text: I am quite (I'd like to say: very) unhappy with the isomerism section, that needs a decent rewrite, trans-effects are completely missing, and optical isomers need to be explained here (the concept with 6-coordinate atoms is more difficult than with 4-coordinate atoms C, N (,S, P)!!  Though the concepts of that should be explained in some page like chirality (chemistry) (I did not have a look on that page, yet, one moment .. OK, inorganic complexes do have a section there, but that section is a plain stub).  I think important here are the effects of isomerism: cis-platin, trans-effect, orientation of reactive sites (in general cis to each other).  --Dirk Beetstra 07:34, 22 May 2006 (UTC)
replies: text: OK, rewrote this section to a readable and more or less correct state, still there is info missing, some linking needs to be done, and see if the concepts in this section are explained sufficiently in the pages linked to. --Dirk Beetstra 21:12, 22 May 2006 (UTC)

text: It is good to hear that the page is getting where it should be, after shuffling ligand and complex I already found that it was a better article, thanks for the assesment and the compliments.  I think when we have these pages (ligand and complex) on a good level, they serve as a decent background for other (inorganic) chemistry concepts that need explaining.  --Dirk Beetstra 07:34, 22 May 2006 (UTC)
thread_title:  Assessment 

message: Is what has been described as Tri-capped trigonal prismatic actually a Triaugmented triangular prism ???  --Dirk Beetstra 21:44, 22 May 2006 (UTC)
replies: text: I dont think so, but I am checking with a math person.  The tricapped trigonal prism is deltahedral but there are no "mu5-vertices", because the square faces are capped.  --Smokefoot 23:09, 22 May 2006 (UTC)
replies: text: Great, thanks.  I have corrected the link in the article.  Cheers!  --Dirk Beetstra 18:32, 23 May 2006 (UTC)

text: P.S. does it make sense to your friend to make a redirect from Tri-capped trigonal prismatic to Triaugmented triangular prism as well?  --Dirk Beetstra 18:32, 23 May 2006 (UTC)
thread_title:  9-coordination - help 

message: Reading this article I think that there are some changes required, which I think need some discussion as so many folk have contributed.For example:-
:Metal complexes The definition as it stands does not include e.g Aluminium etc. Poor or post transition metals need adding to the definition for completeness. Why is there no link to the Ligand article? 
: Geometry The point "the idealised descriptions of 5,7,8...etc" When a square pyramid is so distorted that it becomes an idealised tbp then it really IS a tbp. Perhaps the point to be made is that it is impossible to tell the difference sometimes between e.g a distorted sp and a distoretd tbp.
:Color The reference to Tanabe-Sugano diagrams is fine but simple CFT does quite well for the less competent amongst us, and the CFT article is pretty good and deals with the colors of transition metal complexes quite well whereas the T-S article is not very helpful. 
: Magnetism  "Metal complexes that have unpaired electrons are magnetic". This should read paramagnetic.  Magnetic is misleading- as it usually understood to refer to ferromagnetism.
Axiosaurus 11:08, 27 February 2007 (UTC)
thread_title: Problems with this article

message: Would somebody mind to double check the nomenclature for the porphyrin complexes. www.iupac.org/publications/pac/1987/pdf/5906x0779.pdf
It should be [5,10,15,20-tetrakisphenylporphyrinato]copper(II).  Unless somebody prove me wrong.  —Preceding unsigned comment added by Mandor (talk • contribs) 14:43, 15 October 2008 (UTC)
thread_title:  IUPAC 

message: The history section has no references. Also, it says Werner overthrew the theory that chirality was only for carbon compounds. Did anyone actually believe that? Crystal whacker (talk) 02:03, 16 December 2008 (UTC)
replies: text: I think that there was some sort of conflation of organickiness, chirality, and vital forces that was overthrown by Werner's resolution of carbon-free complexes.  Werner's work in this area does not seem particularly relevant to emergence coordination chemistry but was more of a collateral aspect.  Regarding history sections, they are tricky to write objectively and they often cross the line toward original research.  Russian authors favor Russian contributions, US authors favor US contributions, the French ...  I for one like the idea that coordination chem began with Werner's octahedron. The areas, subheadings, of the field should mention a few sentences on the emergence of each of these themes.--Smokefoot (talk) 03:47, 16 December 2008 (UTC)
thread_title:  History section 

message: Note to Smokefoot:
I see that you have relabeled the Fe(NH3)2F4 complex in the intro as Pt(NH3)2Cl4. I understand the point in the edit summary that you want to show a complex that really exists. However in that case the image needs to be re-drawn. At the moment readers are faced with a caption which says Pt and Cl, but the image shows Fe and F atoms! I think this is much more likely to confuse readers (especially those with little background in inorganic chemistry) than showing a correct image of a complex which doesn't really exist.  Dirac66 (talk) 14:08, 20 November 2009 (UTC)
thread_title:  Iron or platinum complex 

message: The Structure of coordination complexes section currently notes: "Ligands are generally bound to said central atom by a coordinate covalent bond (donating electrons from a lone electron pair into an empty metal orbital), and are thus said to be coordinated to the atom." I believe the statement in brackets is false in the sense that it is not merely lone pairs donating, but pi bonds too. Later mentioned complexes exemplify this, and list ethene as ligand, which does not even have lone pairs.  —Preceding unsigned comment added by 92.241.199.243 (talk) 07:32, 17 April 2010 (UTC)
replies: text: I would say the statement was "incomplete" rather than "false". I have now added a mention of pi-bond ligands with an example.  Dirac66 (talk) 14:05, 17 April 2010 (UTC)
thread_title:  Structure of coordination complexes 

message: Complexation redirects to this article ... should the same be done with decomplexation?
--Andersneld (talk) 19:01, 9 January 2011 (UTC)
replies: text: Not until the article includes at least a word of explanation as to what decomplexation is, I think. Dan ☺ 23:30, 9 January 2011 (UTC)
replies: text: Actually, a short "The term complexation refers to the process of..." wouldn't harm either: what good does a redirect do if it brings you to an article that never mentions the term you searched for? Dan ☺ 23:34, 9 January 2011 (UTC)
thread_title:  Decomplexation 

message: :In chemistry, a coordination complex or metal complex, is an atom or ion (usually metallic), bound to a surrounding array of molecules or anions...
On first reading, it sounds like the coordination complex is just that atom or ion, rather than the whole thing - which I'm fairly sure is wrong. --Chriswaterguy talk 02:29, 20 September 2012 (UTC)
replies: text: Yes, it is the metal plus the ligands. I have reworded this sentence and included the word and. I think it is clearer now. Dirac66 (talk) 03:06, 20 September 2012 (UTC)
thread_title:  Clarity of intro 

message: The whole article currently is about transition metal complexes with short asides referring to other metals. This leads to a very misleading picture, particularly for lanthanide and actinide complexes.  For example the electronic properties section is actually transition metal specific,  but it reads as if it isn't. Lanthanides for example with tightly bound f orbitals are described reasonably well using LS coupling scheme unlike the spin only behavior of t metals. They are only subject to  small crystal field effects - their  pale colors, due to forbidden f-f transitions are virtually independant of the ligand. The magnetism section is similarly one sided. IMHO either new sections on lanthanides, early actininides and main group metals need adding with an appropriate rewrite of the whole article to remove the current "bias", OR we rename it. Axiosaurus (talk) 09:37, 18 November 2013 (UTC)
replies: text: Well, I think that the most useful approach is to consider the readers, not to try to satisfy us specialists.  Readers who want to know about "coordination complexes" are likely to most benefit from a single article on the topic.  We should add a paragraph or two on the f-elements.  Their weak colors could be mentioned in the context of Mn(II) and Fe(III).  You will notice that most textbooks allocate modest space to the lanthanides and actinides, and my sense is that our allocation of emphasis might be similar.  --Smokefoot (talk) 13:30, 18 November 2013 (UTC)
replies: text: I have added a short section on lanthanide colors and tweaked the article where I have spotted generic references to complexes which are specific to transition metals. I have left the magnetochemistry section as is, it is generic enough on reflection. Axiosaurus (talk) 17:46, 19 November 2013 (UTC)
thread_title:  Shouldn't the article be called transition metal coordination complex? 

message: Substituted at 12:15, 29 April 2016 (UTC)
thread_title: Assessment comment

message: OverAll, considering CFT as well, how one can define coordination compound? Vanshita poddar (talk) 16:58, 24 September 2019 (UTC)
thread_title:  Definition 

message: Do halide ions form complexes in water?  If yes, please provide some examples. Vanshita poddar (talk) 17:21, 24 September 2019 (UTC)
thread_title:  Coordination compounds of anions 

message: The first paragraph currently describes ligands as molecules or ions. Can we add atoms to this list? I'm thinking of xenon in tetraxenonogold(II), but there might be other examples. --Ben (talk) 19:49, 18 December 2020 (UTC)
thread_title:  Atomic ligands 

message: : Re my added words "more than one type of donor atom": this is taken from the source textbook by Jolly. In his examples, the isomer pairs have ligands with donor atoms of different elements, such as -NO2 and -ONO, or -NCS and -SCN. I also wondered if this definition includes nonequivalent donor atoms of the same element, but I have not been able to find an external source for this. Related Wikipedia articles are not supposed to be used as sources for facts, although links do help to provide further explanations. So if you can find a supporting external reference, then I would say go ahead and change the wording to "nonequivalent donor atoms" and include an example with two donor atoms of the same element. Dirac66 (talk) 14:53, 16 February 2021 (UTC)
replies: text: Thanks for the original-source text. I can't find any literature examples of the term used for the same element. Our ligand article is more vague: "Polyfunctional ligands, see especially proteins, can bond to a metal center through different ligand atoms to form various isomers." Not "different type", just "different", which could mean different specific serine residues or serine vs glutamic acid, not just serine vs cysteine. My reason for mentioning other articles was definitely not to use them as sources, but instead to find the statement that's most in keeping with a cited ref and synchronize articles that are vague/contradictory and uncited with the the verifiable statment. DMacks (talk) 15:45, 16 February 2021 (UTC)
thread_title:  Linkage isomerism: include nonequivalent donor atoms of same element? 

message: : I see that you have deleted the mention of binuclear complexes by Keyvanmoeini, primarily it appears because the sources were all primary references from the editor's own research group which is what Wikipedia calls refspam. However I think it would still be useful to add a section on binuclear (and multinuclear) complexes, since the article now strongly suggests incorrectly that (almost) all complexes are mononuclear; the only counterexample given is Werner's hexol. Can you write a more satisfactory intro paragraph for bi/multinuclear complexes using secondary sources. Ideally one would want to mention both ligand-bridged and metal-metal bonded complexes.  Dirac66 (talk) 18:38, 7 April 2021 (UTC)
replies: text: I definitely support the mention of multinuclear complexes. Is there a lot to say about them in particular (other than that they exist, and can be bridged and/or metal–metal bonded)? Or do we just need to make sure the general topic of "coordination complex" does not seem limited to single-metal-atom cases? DMacks (talk) 18:43, 7 April 2021 (UTC)
replies: text: All I can think of now is the points you have listed. For ligand-bridged and metal-metal bonded I think it would be good to give a specific example of each. And of course someone may think of more points later. Dirac66 (talk) 20:45, 7 April 2021 (UTC)
thread_title: Binuclear and multinuclear complexes

message: what is the coordination chemistry 2409:4089:119:22C7:B4A1:10FF:FED6:CB5D (talk) 19:23, 9 January 2024 (UTC)
thread_title:  Chemistry