Achieve #3, week 9

[Tianna Nguyen 1I]

Hi, I'm struggling on this problem: "Which geometry or geometries are common for complexes with a coordination number of 6?
hexagonal planar
octahedral
trigonal bipyramidal
pentagonal pyramidal"
I thought the answer was hexagonal planar and octahedral but I can't figure out what the correct answers are. Can someone explain this? Thanks!

[205686400]

Hi! You are completely right in that it asks for the bonds with a coordination number of 6, but if you look at the question more closely it asks which are the most common. Hexagonal planar isn't very common as opposed to the octahedral shape which is often talked about in class.

[Jacqueline Musico 3A]

I think a good rule of thumb is to remember what is covered in lecture. For our purposes, 6 bonds (ligands) has always meant an octahedral shape, so hexagonal planar geometry is likely not relevant to our course. However, Dr. Lavelle did state that a coordination number of 4 could mean either a tetrahedral or a square planar complex, so I see where you could have applied that logic to a six ligand complex.

[Naman Jain 3F]

Hi! I was stuck on this problem too and I thought the same thing as you. It simply is just about which is MOST common, with hexagonal planar not being very common while octahedral is, which is why it's the answer!

[Gabby Burgess 2I]

You are correct on octahedral, but it would not be hexagonal planar as that only occurs in rare instances. Octahedral is the most common and is the one Lavelle had said in class would be common for this course.

[Kathryn Heinemeier 3H]

it would only be octahedral because the other ones aren't very common.

[Bailey Wallace 3A]

Hi! I thought that Seesaw would be common for complexes with a coordination number of 4? Is it not an answer because it is not as common or am I thinking about it wrong?

[Hailey Jeon]

Hexagonal planar does not occur commonly while octahedral shape is a common shape for 6 ligands.

[Aliza Hacking 1A]

hi! as others have said, the most common is octahedral. Dr. Lavelle also mentioned in class that the only geometries we have to know for these compounds are square planar, tetrahedral, and octahedral, which should be helpful in the future :))

[Eric Sun 2G]

I think that the key part would be common structures, and the coordination number of 6 would correspond to octahedral shape most commonly and hexagonal planar would be a lot more rare. Professor Lavelle also mentioned in class that octahedral is the most common shape associated with a coordination number of 6.

[KatieWu 1E]

The correct answer would just be octahedral because it is a common one. Lavelle only taught us about octahedral for shapes with coordination number of 6 so that's why hexagonal planar would not work because in the question it asks for the common ones.