What is a central atom or ion?

Explanation

(i) The central atom or ion is the one that occupies the central position in a coordination entity and binds other atoms or group of atoms (ligands) to itself through a coordinate covalent bond.
(ii).For example ,in ` K_4 [Fe(CN)_6],` the central metal ion is `Fe^(2+) ` In the coordination entity ` [Fe(CN)_6]^(4-) ` the ` Fe^(2+) ` accepts electron pair from each ligand ` CN^(-) ` and thereby forming six coordinate covelent bonds with them.
(iii) It is referred to as a Lewis acid.