Four of us were debating what the actual compounds and terms (scientifically) for water. H2O we all agreed upon until one person said, "..yes and its Hydrogen Dioxide". Myself and 1 of the four challenged that answer by saying, "One does not drink Hydrogen Dioxide"! This turned into an half an hour debate and furious flipping through the internet, (which DID NOT provide a clear and concise answer). Please help make this clear.

  • $\begingroup$ "Please help make this clear". The "di-" prefix means "two". Given that water is $H_2O$ (Two $H$s and one $O$), I think you are quite capable of clearing things up yourself ;) $\endgroup$ Sep 14, 2017 at 13:42
  • 1
    $\begingroup$ The very first hit you get by typing 'hydrogen dioxide' in Google yields the answer you were looking for. $\endgroup$
    – Bdrs
    Sep 14, 2017 at 14:16
  • $\begingroup$ chemistry.stackexchange.com/questions/53533/… $\endgroup$
    – Mithoron
    Sep 14, 2017 at 14:29

2 Answers 2


$\ce{H2O}$ (Dihydrogen monoxide) is water, while $\ce{H2O2}$ (dihydrogen dioxide) is hydrogen peroxide, a strong and unstable oxidizing agent.


The terminology is such that the term "oxide" means a negative ion with a double negative charge, or oxidation state of -2, on a single oxygen atom. Thus, H2O, known as water, can be interpreted as an oxide, but H2O2 cannot, as the -2 "charge" is equally distributed between both oxygen atoms, meaning each has only -1.
Side fact: F2O is not an oxide either, as oxygen hosts positive charge and has the oxidation state of +2, so the compound should be refered to as OF2 and named oxygen difluoride.


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