Sciencemadness Discussion Board

Iron Oxide + Iron Thermite?

DFliyerz - 4-1-2015 at 16:09

This is probably a really dumb question, but... couldn't, in theory, a thermite mixture of iron oxide as the oxidizer and iron powder as the fuel work, and make an oscillating reaction in which the iron powder is converted to iron oxide and the iron oxide is converted to iron, therefore repeating the reaction, albeit at a slightly smaller scale?

Molecular Manipulations - 4-1-2015 at 16:18

Possibly if you use a high oxidation state of iron and have the result be a lower oxidation state, but other wise obviously not.
Fe2O3 + Fe ↔ 3 FeO
I could calculate this and find if it's ΔG is -, but I doubt it.
Wiki says iron exsists in the +5 and +6 oxidation states, but I can't find any oxide of it in either of those states.
No. An oscillating reaction would never happen. If you mantained the mixture at iron's melting point, you would get an equilibrium, but it would obviously release no energy.

[Edited on 5-1-2015 by Molecular Manipulations]

gdflp - 4-1-2015 at 16:25

I doubt that would work. Iron does exist in the +6 oxidation state, but only as ferrates. And, since the reaction is not thermodynamically favorable, not much would happen unless the reaction mixture was heated to a very high temperature. As MM said, you would never get an oscillating reaction.

DFliyerz - 4-1-2015 at 16:25

Quote: Originally posted by Molecular Manipulations  
Possibly if you use a very high oxidation state of iron, but other wise obvously not.
Wiki says iron exsists in the +5 and +6 oxidation states, but I can't find any oxide of it in either of those states.
No. An oscillating reaction would never happen. If you mantained the mixture at iron's melting point, you would get an equilibrium, but it would obvously release no energy.


Wikipedia doesn't have any compound for a +5 oxidation state, but it does have a fairly easy to synthesize +6 oxidation state compound: potassium ferrate.

Molecular Manipulations - 4-1-2015 at 16:36

Yes, but that's technically not an oxide. So yeah, that would work, but you might as well use any other oxidizer. Like the potassium nitrate you would need to make the potassium ferrate.


[Edited on 5-1-2015 by Molecular Manipulations]

DFliyerz - 4-1-2015 at 17:00

What about barium ferrate?

EDIT: I just realized that I'm looking at this wrong.

[Edited on 1-5-2015 by DFliyerz]

DFliyerz - 4-1-2015 at 18:07

Actually, couldn't a +5 or +6 oxide of iron be produced with ozone or another allotrope of oxygen?

macckone - 4-1-2015 at 19:09

You need to look at the thermodynamics of the compounds.
Aluminum Oxide produces a lot of energy when it is formed.
Iron oxides don't produce nearly as much energy.
Magnesium can be used instead of aluminum.
Other mixes are possible.

blogfast25 - 5-1-2015 at 05:33

Quote: Originally posted by DFliyerz  
This is probably a really dumb question, but... couldn't, in theory, a thermite mixture of iron oxide as the oxidizer and iron powder as the fuel work, and make an oscillating reaction in which the iron powder is converted to iron oxide and the iron oxide is converted to iron, therefore repeating the reaction, albeit at a slightly smaller scale?


Erm.... NOOO!

DraconicAcid - 5-1-2015 at 09:00

That's kinda like asking, "If I put a ball on a flat surface, will it roll back and forth really fast?"

DFliyerz - 5-1-2015 at 13:05

Now that the fact that an oscillating thermite reaction wouldn't work has been hammered in, I have a better hypothesis that's been keeping me awake at night: the creation of a +5 or +6 oxidation state iron oxide with ozone or another allotrope of oxygen.

Molecular Manipulations - 5-1-2015 at 15:10

Did you search?
I doubt oxygen will do that. Is ozone really easier for you to get than potassium nitrate?

DFliyerz - 6-1-2015 at 10:09

Quote: Originally posted by Molecular Manipulations  
Did you search?
I doubt oxygen will do that. Is ozone really easier for you to get than potassium nitrate?


What if I want to try and make a higher oxide of iron? :P

blogfast25 - 7-1-2015 at 09:06

Quote: Originally posted by DFliyerz  

What if I want to try and make a higher oxide of iron? :P


There are no stable oxides of Fe above oxidation state III. 'FeO<sub>3</sub>' can exist in very alkaline solution as ferrate anions, FeO<sub>4</sub><sup>2-</sup> but cannot be isolated from it: it immediately falls apart to ferric oxide and oxygen.