A good question.
As with any problem-solving, let's start with what we already know.
O = 1s2 2s2 2p4
S = 1s2 2s2 2p6 3s2 3p4
They both have 6 valence electrons so I guess it's fair to assume they COULD both be 6 coordinate. It certainly explains why they have similar chemistry in some cases.
What's different about them, though?
-Sulphur is bigger than Oxygen
-Oxygen is more electronegative
-Sulphur's valence electrons are further from the nucleus and more shielded. (As it is in the 3rd shell rather than the 2nd like Oxygen)
All of these differences give answers to our question.
-Sulphur is bigger. You can fit more around it. It sounds too simplistic to be true but that's usually the best solution and actually this will be the major deciding factor. Getting 6 atoms around oxygen will be severely crowded, they'll repel each other and it won't be energetically favourable. We call this "Steric Hindrance" and it's the answer to a LOT of chemistry's problems.
- Oxygen is more electronegative. It doesn't like to give electrons away as much as sulphur does...and although fluorine is way more electronegative than either of them...by the time you oxidise oxygen a few times, it's really strongly hanging onto it's electrons. You won't take more than a couple from it.
Note, electronegativity is directly a product of atomic radius and nuclear charge, shielding and the like, it's not some strange standalone effect.
- Sulphur's valence electrons are further away from the nucleus and more shielded. By shielded we basically mean that there are more electrons between the outer electron and the nucleus (we know that's true, oxygen only has 1s2 whereas sulphur has 1s2, 2s2, 2p6 to help shield). If we shield our electrons from the nucleus, there's less positive charge pulling them in - meaning they're easier to pull off and bond with.
Being further away from the nucleus is helpful in the same way...although it's not really the same effect...they're similar enough to mention together.
Hope that's useful.
What are you smoking... Draw the Lewis dot diagram for SF6. 48 electrons to account for. Now place them. The only way to draw it correctly has 12 electrons associated with sulfur. We know that this is only possible for elements with n greater than or equal to 3. That's where d-orbitals become available. Oxygen is n=2 and has no d orbitals available, and we can't associate more than 8 electrons with it. Not because it would be "too crowded since oxygen is small". Yikes. It is not ok to assume oxygen can be greater than 4 coordinate, ever! Even OF4 is impossible; there are 2 electrons we can't account for when trying a Lewis dot structure.
This is the actual reason SF6 is possible.
SF6 is the only stable molecule among the two. Oxygen has no vacant orbitals to bond to 6 F atoms. So it does not form OF6 but S has vacant 3d orbitals and thus it shows the oxidation state of +6 and SF6 exists and is stable.
There is one sulphur, and 6 fluoride (hence the name HEXAfluoride.) Hope this helped! ^^
cis-polyisoprene
Neon has completely filled valence orbitals, obeys octet rule and is hence stable. Chlorine needs one more electron to complete octet and is hence reactive.
it is one of the most stable governments in the world
Chemical reactions are the result of atoms interacting with one another to become more stable.
Iron is a more reactive metal than copper, and so will replace it in a compound. The more reactive a metal is, the more stable it is in a compound, and the less stable it is in its elemental form. So relative to one another, iron is more stable in a compound while copper is more stable as apure element.
adding one more electron
There is one sulphur, and 6 fluoride (hence the name HEXAfluoride.) Hope this helped! ^^
cis-polyisoprene
The geometry for SF6 is octahedral, with a central sulfur atom surrounded by 6 equidistant fluorine atoms situated in the following way: One on the positive x-axis, one on the negative x-axis, one on the positive y-axis, one on the negative y-axis, one on the positive z-axis, and one on the negative z-axis.
A stable fracture is one in which the pelvis remains stable and involves one break-point in the pelvic ring with minimal hemorrhage.
One note to be more stable than any other.
A more stable national economy
it changes the supply of money
Talk to a stable master, buy one or more slots for your pets, and click the empty slot to put your pet in it.
on average, neither one. As men are less (genetically) stable, there are more male geniuses AND more male idiots.
it changes the supply of money