[Corvettaholic]

Is there a cheap, quick, or easy way to free the oxygen atom from iron oxide? What kind of process would you use to break it apart? I know you'll need activation energy of some kind. Just thinking along the lines of there's plenty of locked up oxygen on mars...

[jdurg]

Tee-hee.  Thermite.  

[Corvettaholic]

As much as I'd love to do that, I was thinking of a process that could help produce breathable oxygen from rust. I'd like to try it out around the house, and if it works, well maybe someone can use it for mars someday. And with thermite, don't you get pure iron an aluminum oxide? I want just the oxygen to be all by its lonesome self.

[movies]

You must be able to do it with electrolysis, eh?  Probably takes a lot of energy though.  You'd probably be better of zapping a bunch of water and save yourself the trouble of moving iron oxide from Mars back to earth.

However, you wouldn't want to move all that water to Mars either.

[Corvettaholic]

What'd be the point of hauling iron oxide back home? I was thinking along the lines of living on mars. Gonna run out of air eventually, yes? Well there's PLENTY of oxygen laying around, it just happens to be trapped by iron. In general with any oxide, how hard is it to free the oxygen atom that decided to do some oxidizing? I guess that would depend on what actually got oxidized and bond strength. Would electrolysis work on the iron oxide question?

[budullewraagh]

har har.  there are better sources of O2, specifically H2O2 considering its composition has a greater percent of O by mass than anything else and it decomposes to yield O.  the prospect of making an atmosphere work there is quite sketchy; you'd be better off hauling incredible amounts of CH4, NH3, H2 and H2O gases over there and waiting for an incredibly long time

[Corvettaholic]

Oh I'm not saying put an atmosphere on mars, i'm saying using whats already there as a resource for anyone who wants to visit. Chill in a your little landing pod, scoop up some martian dirt and make something you can breathe out of it. While you're at it, use that iron for something useful too, like buildings. I don't think H2O2 naturally occurs on mars... but that'd be cool if it did. Actually, the only thing I really know that exists on mars is iron oxide, is it Fe₂O₃ or Fe₃O₄? Regardless, whatever you need to do to free the oxygen atom is the same, right?

[movies]

You'd probably need a pretty strong reducing agent to do it chemically.  I wonder if sodium or lithium metal would be strong enough.  You might just end up with NaOH and Fe(0) though.  I guess it depends what kind of solvent you could use.

[budullewraagh]

I wonder if sodium or lithium metal would be strong enough.

yes, they would easily.  any element with a lower standard reduction potential would.  of course, using Li on Fe2O3 would just give you a bunch of Fe and Li2O

[jdurg]

I really don't know of a chemical way to generate oxygen gas from a metal oxide.  Oxygen gas is a pretty good oxidizer, so whatever you use to separate the oxygen from the metal would just wind up reacting with the oxygen before it can escape as a gas.  

[Corvettaholic]

Just out of curiousity, what would happen if you raised the temp enough to make molten iron oxide? Maybe make it easier to attach the oxygen to something else, which in turn it would be easier to seperate the oxygen from?

[jdurg]

The cost of the energy needed to make iron oxide molten would make it VERY non-economical to generate oxygen in that manner.

[ATMyller]

I really don't know of a chemical way to generate oxygen gas from a metal oxide.  Oxygen gas is a pretty good oxidizer, so whatever you use to separate the oxygen from the metal would just wind up reacting with the oxygen before it can escape as a gas.  

Fluoride gas could do it and if you can keep the temperature low enough hardly any oxygen monofluoride generates, but then again hauling huge amounts of fluoride gas to mars is not a very good idea.

[Limpet Chicken]

Might work, they use fluorine gas in some monomethyl hydrazine based hypergolic propellants for rockets I believe, but you would be faced with a whole planet full of nasty and toxic fluoride waste though, and short of chucking the whole thing into the sun after (a bad idea as the fluorine could never be reprocessed) I can't think of any way to dispose of an entire planetfull of iron fluorides.

F might oxidise the iron into a higher oxidation state might it not also?

[jdurg]

The thing is, as soon as the free metal is formed it will react with the fluorine gas, and you'll have an even harder time separating the metal from the fluorine as opposed to the oxygen.