Octet Expansion

[Chiara Frank]

Hey guys! During lecture 20, Dr. Lavelle made a note that octet expansion involves d-orbitals. would anyone be able to explain what octet expansion means and why this would involve d-orbitals? Would this just be due to an increased number of lone pairs and thus regions of electron density? Thank you!

[Vance Liu]

when an octet is fulfilled, it fills up the p sublevel. In order to go beyond an octet, d orbitals need to be utilized (in period 3 and after) in order to accommodate for the extra electrons. Thus d orbitals are also utilized in the hybridization past an octet (dsp3, d2sp3)

[tristenleem3B]

The p-orbital fills up when the atom has filled up all of its octets, so to add more some of the d-orbitals must me utilized.

[Yewon Jang 3K]

Past the 3rd period, the elements can use the d orbital increasing the number of electrons that can be bonded to the element. Since the d orbital can hold up to 10 orbitals, it expands the octet and allows for more than 4 bonds. Hope that helps!

[Gianna Sciole 2F]

when an octet is full, it has 8 valence electrons and fills the p subshell. we know that some elements can have more than 8 electrons in its valence shell and this is where the d-subshell is used. some elements (period 3 and after) can utilize this d subshell to hold more electrons in its valence shell.

[Arjun_Anumula_3E]

Since the d-orbital is in the same principal energy level as a given s and p, leaking electrons from the d orbital to form bonds in period 3+ elements can create a molecule with a lower energy (more stable). This is because if a molecule was forced to place electrons into say the 4s level instead of the 3d, then the molecule would be more unstable.