Metal complexes are formed due to the coordination (donor-acceptor) bond. It differs from covalent bond only in its origin. Once it has been formed, it does not differ from the covalent bond. There must be a donor and an acceptor (metallic ion). The complex may form on the surface. For example, on the surface of cellulose, the ion of copper can be coordinated with the hydroxyl groups. The ion that formed the bond cannot be exchanged for another ion. In cation and anion exchangers, ions can be exchanged for other ions. Here the connection is ionic due to the Coulomb forces. They are easily calculated by Coulomb's law.

Adsorption process takes place commonly by the formation of inner/and outer-sphere complexes between adsorbate and the surface fuctional groups. Strongly bound species adsorbed by means of inner-sphere complex at the surface or 0-plane whilist weakly bound species adsorbed at beta plane by outer-sphere complexes which involve atleast a water molecule between adsorbate and surface.

Attached in article are two examples of metal ion organic ligand complexes comparing chromium III picolinate with that of chromium  III nicotinate.

To my best knowledge, the term "complexion" is not used in chemistry. Plz, clarify your question.

Complexation is one it forms the coordinat bond between it's metal and ligand, it shows in various colors. It will help to determine the colorimetric experiment.

I agree with Yuri Mirgorod

Yes:  the word "complexation" is too imprecise.   A metal-ligand coordination complex can form.  The mechanism of forming a metal-ligand coordination complex is not complexation because all that "complexation" says is that things are [simply ] more complex.  Any mixtures will be more complex because there will be more components present.   For a coordination complex to form and/or to be present,  there must be evidence of  a precise stoichiometry between ligand and metal.

Thank you Yuri Mirgorod Md. Aminul Islam Mohammed Abdullah Issa

Yurii V Geletii By complexion I mean to say, Metal complexes formed during adsorption of heavy metals.

Uddipta Nath Don't use your own terminology, follow IUPAC recommendation.

For a "complex" see

https://goldbook.iupac.org/html/C/C01203.html

"A molecular entity formed by loose association involving two or more component molecular entities (ionic or uncharged), or the corresponding chemical species. The bonding between the components is normally weaker than in a covalent bond. The term has also been used with a variety of shades of meaning in different contexts: it is therefore best avoided when a more explicit alternative is applicable. In inorganic chemistry the term 'coordination entity' is recommended instead of 'complex'. See also: activated complex, adduct, charge transfer complex, electron-donor-acceptor complex, encounter complex, inclusion complex, σ-adduct, π-adduct, transition state"

Yurii V Geletii thank you.