Why do alkaline earth metals form large number of complexes as compared to alkali metals?
Answers
Hey mate here's your answer
Be & Mg do form complexes
e.g. Be with acetylacetone , Mg in chlorophyll.
Mg & Ca form complexes with EDTA.
Small size ( among alkaline earth metals) & high ionic charge makes them suitable candidates to function as central metal ions.
Alkali metals form well known cryptates & crown ether complexes.
Alkali metals(ns1) have much smaller atomic size as compared to transition metals (ns2(n-1)dx). When they form too many co-ordinate bonds, there enters a of factor steric hindrance (Electron repulsions). This increases the energy of the system to such an extent that the complex formed becomes unstable and
d-orbitals allows for more three dimensional interactions (bond formation) than s-orbital.
They can more readily donate electrons, than share these electrons. Hence mostly alkali metals form electrovalent bonds.
Crown ethers are particularly known for their alkali metal ligating/chelating capability. Some alkali metals form complexes with crown ethers because of excellent ligating properties of these ring-like structures.
Eg. Stable Alkali-Metal Complexes of Hybrid Disila-Crown Ethers.
Hope this helps you
Answer:
Alkaline earth metals having a greater tendency to form complexes than alkali metals because of smaller size and higher charge on alkaline earth metal contains as compared to the corresponding alkali metal cations, alkaline earth metal cations have a greater tendency to form complexes.