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Metallic bonding in iron

What would be the charge on the ion?
Original post by Pigster
What would be the charge on the ion?


What level is this?
Reply 2
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Pigster
OP
20
It is a question I'm writing.

I'm not expecting an A-level student to have the right answer and will allow any charge, but wanted to put the 'correct' answer as the right answer in the MS.

I suspect it won't be as simple as A-level definition will allow, in a similar way to oxidation states can be decimals and rates don't have to be integers.
Original post by Pigster
It is a question I'm writing.

I'm not expecting an A-level student to have the right answer and will allow any charge, but wanted to put the 'correct' answer as the right answer in the MS.

I suspect it won't be as simple as A-level definition will allow, in a similar way to oxidation states can be decimals and rates don't have to be integers.


Well the answer I would give depends on the level. Lets take uni level... Well the whole ions in a sea of electrons isn't really how we view things.

I feel a safe answer is to take off the d-electrons down to the next half/full shell, so for iron +3 making it d5 config.
Reply 4
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Pigster
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Ta.

With my neck stretched out, I suspect Band theory is where you're alluding to.

But 3+ will do.
Original post by Pigster
What would be the charge on the ion?


Depends on chemical context
Do a flame test and check, if it's a 'dirty green' colour then it's the dication
if it's a reddish brown then it's the trication
Reply 6
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BJack
19
Original post by notathuggee
Depends on chemical context
Do a flame test and check, if it's a 'dirty green' colour then it's the dication
if it's a reddish brown then it's the trication


The chemical context is metallic iron. Hence metallic bonding....
Original post by BJack
The chemical context is metallic iron. Hence metallic bonding....


well if you leave the iron in air it'll rust
and as if by magic
Fe3+ appears
Original post by BJack
The chemical context is metallic iron. Hence metallic bonding....


but seriously, how many electrons does each Fe atom contribute to the 'sea of delocalised electrons' model?
As many as it can, surely.
Reply 9
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Pigster
OP
20
26?

(written with incredulous eyebrows)
OK..... So.....

Metallic bonding. This is a collection of very many orbitals overlapping so that there is an almost continuous set of energy levels.

As with all MO bonding, only the higher energy orbitals are generally included in the bonding, though all orbitals have some influence. The electrons do not sit in a sea, they sit in orbitals which extend throughout the whole crystal.

I gave the answer of 3 earlier, as under the ionised model, this is reasonable. The loss of the 2 4s electron and the d6 electron to make a stable d5 arrangement is logical in this framework.

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