Reference(NCERT book of India); enter image description here

My professor has taught me that $\ce{Na2O}$ and $\ce{Na2O2}$ are the most common oxides of sodium, but in my reference book it is written that they are $\ce{NaO2}$ and $\ce{Na2O2}$. I have searched the net but couldn't find anything about their relative occurrence (percentage). Can anyone please clarify which of the above is correct?


1 Answer 1


Sodium superoxide $\ce{NaO2}$ is a rare substance that can only be made by burning sodium at high pressure. Sodium peroxide $\ce{Na2O2}$ is common: it is formed when metallic sodium is burning in oxygen or air at ordinary pressure. The usual (and "logical") monoxide $\ce{Na2O}$ is not common. It is the result of the pyrolysis of different salts, like sodium carbonate, at very high temperature ($\sim2000\ \mathrm{^\circ C}$). Both the Handbook of Chemistry and Physics and the Merck Index give the properties of $\ce{Na2O}$ and $\ce{Na2O2}$: density, melting point. The superoxide $\ce{NaO2}$ is not mentioned, at least in my edition.

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    $\begingroup$ @Maurice.Thanks for your answer,but can we comment which among $\ce{NaO2 and Na2O }$ is more common? $\endgroup$
    – user120451
    Feb 19, 2022 at 14:54
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    $\begingroup$ "The superoxide NaO2 is not mentioned" is not true. Sodium superoxide is entry 2650 in the CRC Handbook of Chemistry and Physics (96th edition) with mp 552 °C and density 2.2 g/ml. Besides, I'm not sure the missing database entry is a good argument that speaks anything about the abundance. Also, OP indeed asks for comparison between $\ce{NaO2}$ and $\ce{Na2O},$ not $\ce{Na2O2}.$ $\endgroup$
    – andselisk
    Feb 20, 2022 at 2:50

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