I put some iron nails in water, and obviously, those started oxidizing, making those hydrogen bubbles. Some days after, the water was orange, indicated that the FeO has just dissolved in it. I found some days after that the solution was oversaturated, and the insoluble FeO was at the bottom of the container. I need all the FeO, even the one solved. If I heat and evaporate the water, will I lose the FeO? Or will the water leave it alone to use? I think I would get steel 0.2, but I am not sure.

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    $\begingroup$ Corrosion works completely different then you think... $\endgroup$
    – Mithoron
    Apr 2, 2022 at 0:32
  • $\begingroup$ I would be very thankful if you can give me some investigation to learn about the topic $\endgroup$ Apr 2, 2022 at 0:33
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    $\begingroup$ Well, there's plenty of resources on the internet. My concern is that I don't get what are you really asking about. Whatever "would get steel 0.2" is supposed to mean in particular? $\endgroup$
    – Mithoron
    Apr 2, 2022 at 0:38
  • $\begingroup$ I am asking if I can get FeO or Fe2O3 evaporating the water, because I have seen in some information sources that it will get a steel-looking compund, so I don't want to get some other thing, I want the ferrous or ferric oxide. $\endgroup$ Apr 2, 2022 at 0:44
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    $\begingroup$ The title is too vaque and not related to the post. $\endgroup$
    – Poutnik
    Apr 2, 2022 at 7:46

1 Answer 1


It is not FeO ( ferrous +2 iron), ferrous is unstable in the presence of air. And FeO is black as high temperature mill scale. You have a ferric ( +3) compound , likely some kind of hydroxide. The lab I worked in analyzed ( XRD) at least one "rust" sample a day for corrosion evaluation. The iron compounds were generally not easy to pin down to a specific compound using the Fink XRD Index.

  • $\begingroup$ So, that dust in the bottom of the recipient is ferric hydroxyde? (Fe(OH)3)? $\endgroup$ Apr 2, 2022 at 0:32
  • $\begingroup$ If it is dark brown, the stuff is $\ce{Fe(OH)3}$. If it is black, it is $\ce{Fe3O4}$. If it is pale brown, it is $\ce{FeO(OH)}$. $\endgroup$
    – Maurice
    Apr 2, 2022 at 15:23

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