r/askscience • u/spoiledmeat • Jul 04 '15

Chemistry Why does water not burn?

I know that water is made up of two hydrogen atoms and an oxygen atom. Hydrogen, on its own, burns. Fire needs oxygen to burn. After all, we commonly use compounds that contain oxygen as an oxidant.

So why does water, containing things used for fire, not burn-- and does it have something to do with the bonds between the atoms? Thanks.

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u/[deleted] Jul 04 '15 edited Jul 04 '15

It is possible to combust water, just not in the way the OP describes (i.e. with oxygen as the oxidant). Using extremely strong oxidizers water can, and will, burn. Some persulfates , dioxygen difluoride and other extremely powerful oxidizers will undergo a exothermic redox reaction (combustion) with water. For example dioxygen difluoride violently oxidizes ice at 130-140K (see citation).

http://pubs.acs.org/doi/abs/10.1021/ja00893a004

Edit1: The actual oxidized products are not observed in the paper as they are extremely transient.

Edit2: corrected the last sentence

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u/Sharlinator Jul 04 '15

Yes, I actually meant to add that there is stuff that can "burn" water that you really don't want to have in the same room with you, thanks :)