Which type of hybridization is found in the compound PF5 ?

##"sp"^3"d"##

In order to determine the of the central phosphorus atom in phosphorus pentafluoride, ##"PF"_5##, you must first draw the compound's .

The molecule will have a total of ##40## , ##5## from the phosphorus atom, and ##7## from each of the five fluorine atoms.

The phosphorus atom will be the molecule's central atom. It will form single bonds with the five fluorine atoms.

These will account for ##10## of the ##40## the molecule has. Each fluorine atom will have three lone pairs of electrons, which will account for the rest of the .

The molecule's Lewis structure will look like this

Now you need to focus on the central atom, more specifically on how many regions of electron surround the central atom - this is known as the steric number

A region of electron density can be a covalent bond - single, double, and triple bonds all count as one region of electron density - or a lone pair of electrons.

Notice that phosphorus is bonded to five fluorine atoms and has no lone pairs of electrons attached, which means that it is surrounded by a total of five regions of electron density, which is equivalent to saying that it has a steric number equal to ##5##.

The steric number gives you the number of hybrid orbitals. In this case, a steric number of ##5## means that the phosphorus atom will have ##6##

• one s-orbital
• three p-orbitals
• one d-orbital

As a result, the central atom will be ##"sp"^3"d"## hybridized.