Talk:Ligand

message: This discussion is being held at Talk:Ligand (biochemistry).  Single word comment moved there. Walkerma 02:49, 17 December 2005 (UTC)
replies: text: Thank you for the constructive criticism and positive feedback.  It is quite helpful. User:Ceyockey (talk to me) 16:56, 19 February 2006 (UTC)
thread_title: Merge proposal

message: The charge on the central atom (called the oxidation number) constrains the number of ligands that may be bonded because each type of ligand donates a characteristic number of electrons, and there is a requirement for overall neutrality. This sentence was removed. It is strictly true that neutrality is required for a molecule overall, but the complex may be a complex ion (positive or negative) and most transition metals bond octahedrally regardless of the charges of the ligands or their own oxidation states. I see what the author of the above sentence was getting at, but how could it be better said? Srnec 21:59, 19 April 2006 (UTC)
thread_title: Removed sentence

message: I have put the remainder of the ligands in a table, which is far from complete, so I have added an 'expand' to it.  Things that need to be done:
* Some of the ligands can be placed in the upper table (the one sorted by field-strenght).  So which can be placed there, should be moved to their appropriate place.
* There are some common ligands missing, so they have to be added.
* Table needs more filling, most formulae are missing, e.g.
* I have no clue about table-formatting, I think the 2 tables should be similar, can someone help with that?
Hope you can help.  Cheers!  --Dirk Beetstra 13:17, 29 May 2006 (UTC)
thread_title: table(s) of common ligands - please expand

message: There are now two statements above the page, where the word ligand is used in another sense than the inorganic way, should 'ligand' not be a disambiguation page, pointing towards ligand (biochemistry), ligand (pharmacology) and ligand (chemistry) (the latter should then contain the information now on ligand)??  --Dirk Beetstra 09:03, 3 June 2006 (UTC)
replies: text: I created ligand (disambiguation), which points to the respective pages, I now see, that many pages linking to ligand (many of these links) actually should point to ligand (biochemistry).  --Dirk Beetstra 10:06, 3 June 2006 (UTC)
thread_title:  Disambiguation 

message: The current article (July 9, '06) states:
"In chemistry, a ligand is an atom, ion, or molecule (see also: functional group) that generally donates one or more of its electrons through a coordinate covalent bond to, or shares its electrons through a covalent bond with one or more central atoms or ions (these ligands act as a Lewis base. Fewer examples exist where a molecule can be described as a ligand that accepts electrons from a Lewis base (hence, the ligand acts as a Lewis acid)."
Whether we like it or not, the second sentence contradicts the first.  We can't begin the article by saying in effect " ligands are Lewis bases, unless they are Lewis acids, and oh, sometimes they donate one electron to make covalent bonds" - which is what it currently says. I dont have any great ideas about how to resolve the current wide-open definition.  
My recommendation would be to admit that the nomenclature is imperfect but that generally, ligands are considered to be the Lewis base component of an adduct.  Thus BF4- has four fluoride (vs fluorine) ligands. 
--Smokefoot 18:12, 8 July 2006 (UTC)
replies: text: I see your problem, but to add to this discussion .. isn't BF3 a ligand for F- in BF4- ... ??  I'll think about it ..  --Dirk Beetstra T C 23:45, 8 July 2006 (UTC)
replies: text: Welcome back. BF3 would not be considered to be a ligand for F- in BF4- ...  Its the other way around.  at least around here.  --Smokefoot 00:23, 9 July 2006 (UTC)
replies: text: Thanks!  Yes, the general way is to define the fluoride to be the ligand.  But, when looking at the coordination chemistry of the fluoride, BF3 is the ligand ... But I think we will have to have a look in textbooks for this one, how it is defined.  To my feeling, people think of ligands as the things coordinating to a metal centre, and metal centres in general want electron density, and therefore most of the molecules considered ligands are Lewis bases, i.e. electron donating things.  But when applying the same to organics .. H is the ligand for C in methane?  Or would you then argue that CH3- is the ligand for H+, just because the ligand has to donate electrons...??  --Dirk Beetstra T C 08:17, 9 July 2006 (UTC)
thread_title: You can't have it both ways, i.e. L = donor, covalent, and acceptor

message: Note: The entries in the table are sorted by field strength, binding through the stated atom (i.e. as a terminal ligand), the 'strength' of the ligand changes when the ligand binds in an alternative binding mode (e.g. when it bridges between metals) or when the conformation of the ligand gets distorted (e.g. a linear ligand that is forced through steric interactions to bind in a non-linear fashion). hellow
hellow = vandalism right? —The preceding unsigned comment was added by 144.136.38.19 (talk) 09:36, 19 February 2007 (UTC)
thread_title:  vandalism 

message: So whats the goal with the tables - list every ligand?  As we known virtuallyevery organic compound is a ligand under the right circumstances.  If one excludes agostic complexes, then every amine, phosphine, ether, alkene, arene, heterocycle... Some thought might be given to a classification scheme (perhaps based on donor atoms and denticity and branched vs linear) otherwise this article collapses under the weight of minutia.  The second table is entitled "Other general (should be 'generally') encountered ligands (alphabetical)" Note the word "general." IMHO.--Smokefoot (talk) 15:04, 18 November 2007 (UTC)
replies: text: exactly what I would recommend: "general ligand classes", not ligands.  And eventually, we might have articles on each of these classes (tertiary phosphines, beta-diketonates, cyclopentadienyls, dienes, etc).--Smokefoot (talk) 15:50, 18 November 2007 (UTC)
thread_title: Every ligand?

message: Can we have another image of a more conventional ligand?  The one posted was obscure.  The legend was incidentally ungrammatical and misspelled. Tmangray (talk) 16:51, 2 April 2008 (UTC)
thread_title: Image

message: Metal ions bound to strong-field ligands follow the Aufbau principle, whereas complexes bound to weak-field ligands follow Hund's rule.
According to its own article the Aufbau principle seems to include Hund's rule, so what is meant by "whereas" (or by Aufbau principle and Hund's rule) here?  —Preceding unsigned comment added by 194.81.223.66 (talk) 09:18, 18 August 2008 (UTC)
thread_title: Clarify Hund's rule

message: There is no mention of L-type and X-type, their distinction and meaning.  While a trivial distinction that falls out of the electron counting, these are terms in use and I wonder if they don't warrant at least a mention somewhere within Wikipedia.  Are there any thoughts?Gaedheal (talk) 15:05, 29 October 2009 (UTC)
thread_title: L-type and X-type

message: ""Ligand, in chemistry, is any atom or molecule attached to a central atom, usually a metallic element, in a coordination or complex compound. The atoms and molecules used as ligands are almost always those that are capable of functioning as the electron-pair donor in the electron-pair bond (a coordinate covalent bond) formed with the metal atom.
Examples of common ligands are the neutral molecules water (H2O), ammonia (NH3), and carbon monoxide (CO) and the anions cyanide (CN-), chloride (Cl-), and hydroxide (OH-). Occasionally, ligands can be cations (e.g., NO+, N2H5+) and electron-pair acceptors. The ligands in a given complex may be identical, as the CO ligands in Fe(CO)5 and the H2O ligands in [Ni(H2O)6]2+, or different, as the CO and NO ligands in Co(CO)3(NO).
A metal ion in solution does not exist in isolation, but in combination with ligands (such as solvent molecules or simple ions) or chelating groups, giving rise to complex ions or coordination compounds. These complexes contain a central atom or ion, often a transition metal, and a cluster of ions or neutral molecules surrounding it.
Ligands are ions or neutral molecules that bond to a central metal atom or ion. Ligands act as Lewis bases (electron pair donors), and the central atom acts as a Lewis acid (electron pair acceptor). Ligands have at least one donor atom with an electron pair used to form covalent bonds with the central atom.
The term ligand come from the latin word ligare (which meaning to bind) was first used by Alfred Stock in 1916 in relation to silicon chemistry.
Ligands can be anions, cations, or neutral molecules. Ligands can be further characterized as monodentate, bidentate, tridentate etc. where the concept of teeth (dent) is introduced, hence the idea of bite angle etc.
Attachment of the ligand to the metal may be through a single atom, in which case it is called a monodentate ligand, or through two or more atoms, in which case it is called a didentate or polydentate ligand."" 49.185.137.168 (talk) 13:52, 15 May 2022 (UTC)
thread_title:  A ligand in chemistry ... 

message: — Assignment last updated by CHEM 300 UBC CJA (talk) 18:02, 8 November 2023 (UTC)
thread_title: Wiki Education assignment: CHEM 300