# Difference between subshell and sub-subshell?

I consider the s p d f orbitals as a subshell, but I have heard about the term sub-subshell. what is the difference between these two?

• I haven’t really heard it, but I can imagine it meaning the $\mathrm{t_{2g}}$ and $\mathrm{e_g}$ sub-subshells of the d-subshell, for example. – Jan Sep 14 '16 at 17:01
• There seems to be some usage in relativistic chemistry, Google throws up some stuff but I hardly understand them. For example in this question by ron, I believe the p(1/2) and p(3/2) can be called sub-subshells sometimes, since they are not quite orbitals but they arise from the splitting of a subshell (which is degenerate in the non-relativistic picture). – orthocresol Sep 14 '16 at 17:29

As you pointed out the the s, p, d, and f denoted subshells of atoms.

The term sub-subshells is very uncommon. I did find a couple of uses.

Materials Science By G. K. Narula, K. S. Narula, V. K. Gupta

pdf file about Modern Atomic Mechanical Theory, page 24

What the authors are noting is that the 2p subshell will have three orbitals which can support two electrons each. Each of these three orbitals is being referred to as a sub-subshell.

As I said it seems a very uncommon term, and I'd suggest you avoid using it.

• so u mean that instead of sub-subshell I use the word orbitals? – Dawood Ibrar Bilandkhel Sep 14 '16 at 17:05
• and what if orbital is used for s p d f and then what is a subshell – Dawood Ibrar Bilandkhel Sep 14 '16 at 17:05
• Let's just agree that the s, p, d, and f denote subshells of atoms and not peel this back that far. – MaxW Sep 14 '16 at 17:14
• agree with that – Dawood Ibrar Bilandkhel Sep 14 '16 at 17:17
• I can't think of a good word to replace the concept of sub-subshell in the way that the authors cited used the term. In general in chemistry if the orbitals in a subshell weren't degenerate then we'd use nomenclature to explain the specific electronic configuration. If the orbitals are degenerate then we'd say "the 2p orbitals," or "the p orbitals." – MaxW Sep 14 '16 at 17:20

A subshell/orbital for example 2p is further divided into Px,Py&Pz.These Px,Py,&Pz are called sub-subshells/suborbitals.It is also same in case of s,p,d,f orbitals.But for s-orbitals there is no suborbitals and s is suborbital itself. Hope this help.