(a,c,d) Tetrahedral complexes are favoured by steric requirements, either simple electrostatic repulsion of charge ligands or vander wall's repulsions of large one.

Tetrahedral complexes are thus generally favoured by large ligands like Cl – , Br – , Ι – and PPh 3 and metal ions of three types ;

those with a noble gas configuration such as Be 2+ (nsº) ;

those with pseudo noble gas configuration (n–1)d 10 ns 0 np 0 , such as Zn 2+ , Cu + and Ga 3+ , and

those transition metal ions which do not strongly favour other structure by virtue of the CFSE, such as Co 2+ , d 7 .