Thread: why Pz orbital for sigma bonding?

hello,
could someone plz tell me why Pz orbital is involved in sigma bonding whereas other two P orbitals are involved in pi bonding?

It's a completely arbitrary convention with no significance, p_x, p_y and p_z orbitals are identical except for orientation, there is no preference for one to form only sigma bonds and the others only pi binds you could equally correctly say that one of others forms the sigma bond and the remaining two form pi bonds.

Originally Posted by chinna

hello,
could someone plz tell me why Pz orbital is involved in sigma bonding whereas other two P orbitals are involved in pi bonding?

Yes it's arbitrary, as PhDemon says.

My recollection is that there is a convention to treat anything that makes the environment of the atom anisotropic along one dimension (for example a dipolar electric or magnetic field) as aligned along the z axis. Then you define x and y accordingly. The influence of a second atom, bound to the first, is one such case.

ok thanks a lot