What is the difference between sp3d2 and d2sp3?!?
Octahedral coordination: sp3d2 and d2sp3
Many of the most commonly encountered transition metal ions accept electron pairs from donors such as CN– and NH3 (or lacking these, even from H2O) to form octahedral coordination complexes. The hexamminezinc(II) cation depicted below is typical.
In sp3d2 hybridization the bonding orbitals are derived by mixing atomic orbitals having the same principal quantum number (n = 4 in the preceding example). A slightly different arrangement, known as d2sp3 hybridization, involves d orbitals of lower principal quantum number. This is possible because of the rather small energy differences between the d orbitals in one “shell” with the s and p orbitals of the next higher one— hence the term “inner orbital” complex which is sometims used to describe ions such as hexamminecobalt(III), shown below.. Both arrangements produce octahedral coordination geometries.