Complexes involving multidentate ligands are more stable than those with only unidentate ligands in them. The underlying reason for this is that each multidentate ligand displaces more than one water molecule . ... An increase in entropy makes the formation of the chelated complex more favourable.
How does chelate effect stabilize the complex?
The Chelate Effect is that complexes resulting from coordination with the chelating ligand is much more thermodynamically stable than complexes with non-chelating ligands. ... Note as well that there is a dramatic increase in the size of the ΔS° term for adding two compared to adding four monodentate ligands.
Why chelate complexes are more stable?
Chelating ligand can form a ring with central metal. Therefore it have ability to regulate electron with in ring. Because of it there is more force of attraction between central metal ion chelating agent , therefore, they are more stable.
Are chelate complexes stable?
Chelates are more stable than nonchelated compounds of comparable composition, and the more extensive the chelation—that is, the larger the number of ring closures to a metal atom—the more stable the compound.
What makes a complex more stable?
1 Charge on metal cation. In metal cations, higher oxidation state forms more stable complex than lower oxidation states with ligands such as NH 3 , H 2 O, etc. Even few exceptions are there like CO, PMe 3 , o-phenanthroline, bipyridyl, CN − , which form more stable complex with lower oxidation state metals.
Why is K+ much more stable than K2 +?
Atomic number of k = 19, ... We see that, Pottasium(k) has 1 electron in it’s outermost shell, So k+ will have, 8 outermost electrons , According to Octet rule, K+ will be more stable !.
Which complex has highest stability?
[Cd(CN) 4 ] [CdCl 4 ]
What is chelate effect example?
The complex which contains chelating ligands is called Chelates. Complexes containing chelate rings are more stable than complex without rings. This is called the chelate effect. ... Examples: [Co(en)3] 3 + is more stable than [Co(NH3)6] 3 + where Ethylenediamine (en) is an example of a bidentate ligand.
Why does chelate effect occur?
When a chelating ligand replaces several monodentate ligands, the result is an increase in the number of free molecules in the system , meaning a relatively large increase in entropy. This is the major energetic factor driving the chelate effect.
What causes chelate effect?
The main cause of the chelate effect is the effect of reaction entropy when the complex is formed . Thus, the reaction [Cu(OH 2 ) 6 ] 2 + +en → [Cu(en)(OH 2 ) 4 +2H 2 O results in a net increase in the number of molecules (from 2 to 3). ... As a result, the chelate reaction has a larger reaction entropy and is more favourable.
Which of the following is the strongest ligand?
According to this series $CO$ is the strongest ligand among the following because carbon is donor in this, it has double bond $(C = O)$ and is positively charged. Note: The strength of any ligand is determined by the amount of crystal field energy (CFT).
Why are chelating ligands?
Chelating ligand is a ligand which is mostly attached to a central metal ion by bonds that are from two or more donor atoms . In other words, these are a type of ligands where the molecules can form several bonds to a single metal ion or they are ligands with more than one donor site.
Why are chelating ligands preferred over monodentate ligand?
So as ∆S increases, K value increases since ∆H valuea are almost the same). Thus chelate effect is entropy driven . More the no: of binding groups a ligand has; more +ve ∆S is and thus higher the value of Kf will be.
How do you know if a complex is stable?
The most important characteristics of the central atom, determining the stability of the complex compound, are the degree of oxidation (charge on the central ion in the case of ionic complexes) , the dimensions, and the electronic structure.
How do you know which complex is most stable?
Among the given complexes, in [Ni(CN)4]3− , the charge of central metal ion is highest, ie, +1 while CO is the strongest field ligand. Hence, [Fe(CO)5] is the most stable complex among the given complexes.
Which of the following complex is more stable thermodynamically?
C2O2−4 is the bidentate chelating ligand. Therefore, when it forms the complex with Fe it forms a ring as it acts as the chelating ligand. Hence, the most stable complex is [Fe(C2O4)3]3− . Therefore, the correct option is (C).
