Why 2d orbital does not exist

Which does not exist ?

Which d-orbital does not have four lobes?

A: The degeneracy of d-orbitals is lost under strong field ligand R: The degeneracy of d-orbitals does not get lost under weak field ligand

Why boron does not exist as B^(3+) ion in solution or in compound ?

Which molecule does not exist ?

Which molecule does not exist ?

Why boron halides do not exists as a dimer. While AlCl_(3) exists as Al_(2)Cl_(6) ?

Show that Lim_(x to pi/2) tan x does not exist .

Use molecular orbital theory to explain why the Be_2 molecule does not exist.

On the basis of molecular orbital theory, explain why He_2 does not exist whereas Hezexists?