Order of priority in hybridization of d-orbitals

During hybridization of d-orbitals why the $d\_{z^2}$ and $d\_{x^2-y^2}$ orbitals are used up before the $d\_{xy}$, $d\_{yz}$ and $d\_{zx}$ ?




The rotational frame of reference which defined which axis is the z-axis is changed such that $d\_{z^2}$ and $d\_{x^2-y^2}$ are hybridized first is a convention / practice.


In theory (meaning mathematically), you should be able to get equivalent geometry if you used the other d orbitals for hybridzation.


Basically the donut thing is weird enough we try to fold it in so we can deal with the more normal cloverleafs as leftovers.


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