# Would LOX+$NO_2$ or LOX+$N_2O_4$ make a good oxidizer mix?

We know that oxygen is the "king" of oxidizers:

• non-toxic (unlike fluorine)
• cheap
• only an oxidizer (potassium nitrate, for example, comes with K and N which aren't what we want)
• no need for catalysis ($H_2O_2$)

But with all that being said, we still have to contain it inside a very cold tank (90K) or a very pressurized one (so very heavy…).

With all that in mind, would it be a good idea to use nitrogen dioxide ($NO_2$) and/or dinitrogen tetroxide($N_2O_4$) to stabilize the $O_2$? (I mean raising its boiling point.) It would reduce the need for cooling machines (not cheap) while letting the mix be a good oxidizer.

EDIT 1 : As Organic Marble pointed out it seems that $N_2O_4$ could replace $NO_2$ in the question. But because $NO_2$ and $N_2O_4$ are always in chemical equilibrium, filling a tank with one of them is, I guess, filling it with both of them ?

And if any of you think of another good oxidizer that would do the trick, feel free to share the idea!

• +Nathan Tuggy Thank you for the correction :) – YaJBoy Sep 24 '16 at 22:55
• Interesting question. My usual sources make no mention of it being used as rocket oxidizer, although an Air Liquide fact sheet lists it as a use. It seems to be quite toxic but that hasn't prevented the use of other propellants. – Organic Marble Sep 25 '16 at 2:09
• @OrganicMarble wikipedia says " it was used in the Titan rockets, to launch Project Gemini, in the maneuvering thrusters of the Space Shuttle, and in unmanned space probes sent to various planets" (en.wikipedia.org/wiki/Nitrogen_dioxide#Uses) – YaJBoy Sep 25 '16 at 6:08
• No, that is nitrogen tetroxide, a different compound. Is that what you are really asking about? – Organic Marble Sep 25 '16 at 13:29
• @OrganicMarble It is said in this page that nitrogen tetroxide stay in an "equilibrium mixture" with $NO_2$. So I didn't made the distinction. it's (I think) the same question ... no? – YaJBoy Sep 25 '16 at 14:55