Center elements with six electron groups can have zero to 2 lone pairs to give three possible molecular geometries. So if we have 6 electron groups, the combinations that exist are we can have six bonding groups which are surrounding elements and 0 lone pairs. Or we could have 5 surrounding elements and 1 lone pair. Or we could have 4 surrounding elements and two lone pairs on the central element.
Here we have some good examples of this. Here we have sulfur hexafluoride, here we have chlorine, PETA, bromide and then here we have Xenon tetrachloride. Now their visualizations for sulfur tech on hexa. On fluoride we have sulfur in the center with its six surrounding elements 6 surrounding fluorines. Here the molecular geometry would be octahedral.
For the next one we have chlorine pentabromide and if we were to visually show it, we can see that it looks like a pyramid. And this pyramid has a base that's square shaped, so that's why its name is square pyramidal. So just remember if you have a central element that has five surrounding elements in one lone pair, it's square pyramidal.
Then finally the last one. Here we have 4 surrounding elements and two loanpayers. Here it would take on a square shape and here it's on a flat plane. So that's why this is called square planar or square planar. So these are the three molecular geometries that exist if you're dealing with six electron groups on your central element.
