Sciencemadness Discussion Board

Any thing decomposes to give fluorine or chlorine gas ?

KonkreteRocketry - 30-4-2013 at 22:43

Is there any thing that decomposes to give fluorine or chlorine gas ? and not at too elevated temperature, around few hundred degrees ? So like a oxidizer ?



[Edited on 1-5-2013 by KonkreteRocketry]

confused - 30-4-2013 at 22:45

chlorine dioxide...but it's kind of impractical...what are you using it for?

most chlorine oxides are relativly unstable

[Edited on 1-5-2013 by confused]

KonkreteRocketry - 30-4-2013 at 22:53

Quote: Originally posted by confused  
chlorine dioxide...but it's kind of impractical...what are you using it for?

most chlorine oxides are relativly unstable

[Edited on 1-5-2013 by confused]


I just want to like read about some oxidizers that uses halogens instead of oxygen to burn. For example Chlorine trifluoride, but like more practical.

weiming1998 - 1-5-2013 at 08:21

You'll be hard-pressed to find/make anything that decomposes to give F2. Only very strong fluorinating (MnF3, XeF2, AgF2, etc) will be able to decompose, releasing fluorine, at few hundred degrees. They are all very unstable in the presence of water, hydrolysed by moisture in the air to form poisonous hydrogen fluoride. So that's not a very good idea.

More things decompose at that temperature to form Cl2, but they're mostly covalent compounds that would boil away before decomposing. Most are quite reactive with water (an exception being the really expensive gold chloride and the chlorides of platinum group metals),so it would be hard to store. But then, being less electronegative than oxygen, chlorine is less reactive as an oxidizing agent than oxygen, so there's no point. However it is worth noting that aluminium/magnesium can form a mixture with anhydrous (brown) copper (II) chloride that can burn with a small, bluish flame.

franklyn - 1-5-2013 at 12:42

http://pubs.acs.org/doi/abs/10.1021/ic00241a001

2 KMnO4 + 2 KF + 10 HF + 3 H2O2 => 2 K2MnF6 + 8 H2O + 3 O2

2 K2MnF6 + 4 SbF5 => 4 KSbF6 + 2 MnF3 + F2


* click on ' Search ' at the upper left right here on this very page you

are now reading then enter K2MnF6 into the top ' Search for : ' space

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AndersHoveland - 2-5-2013 at 14:15

At 400°C, a mixture of solid K2NiF6 and KF disproportionates/decomposes to form K3NiF6 and F2. The reaction is reversible at 250°C.

NiF4 exists, if a limited ammount of strong fluoride ion adbductor is used to remove the coordinated fluoride ions.

MnF3 decomposes to manganese(II) fluoride above 600°C. MnF4 does not exist.

AJKOER - 3-5-2013 at 18:35

Would something more simple work like mixing NH4Cl and MnO2 and heating?

The logic:

NH4Cl --Heat to 338C--> NH3 (g) + HCl (g)

4 HCl (g) + MnO2 ---> MnCl2 + 2 H2O (g) + Cl2 (g) (see Wiki http://en.wikipedia.org/wiki/Cl2 )

2 NH3 (g) + 6 MnO2 --450C--> N2 (g) + 3 H2O (g) + 3 Mn2O3 (speculative see http://pubs.acs.org/doi/abs/10.1021/ie9709345 )

So a possible net reaction:

4 NH4Cl + 13 MnO2 --Heat--> MnCl2 + 8 H2O (g) + Cl2 (g) + 2 N2 (g) + 6 Mn2O3

Adding a metal (like Mg) to the mixture to react with the projected large amount of water vapor (although, I would assume as more likely a partial decomposition only of the NH3 with MnO2) might prove to be interesting.


[Edited on 4-5-2013 by AJKOER]

mayko - 4-5-2013 at 07:07

If you haven't already, you might explore magnesium/teflon mixtures. The high enthalpy release of Mg + F2 -> MgF2 drives the decomposition of the polytetrafluoroethylene into carbon and fluorine. I always thought it was a clever quasi-thermite :)


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KonkreteRocketry - 9-5-2013 at 06:45

Does XeF4 decompose to XeF2 ?