Does ozone have a color or is it colorless? I have heard that ozone has a bluish color.

Could someone explain this observation scientifically?

  • 2
    $\begingroup$ This is pretty Googleable, and I'm closing it as such. If anyone disagrees, please let me know (with a reason) $\endgroup$ Commented Jul 9, 2012 at 20:17
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    $\begingroup$ Well, of course this is googlable, but why closing for "too localized"? $\endgroup$
    – Georg
    Commented Jul 10, 2012 at 8:43
  • $\begingroup$ I googled this. I got two answers. I just say it in question. Bluish and colorless. Also a specific explanation not getting. Also I think a question closing because of its Googleable not a good practise and discouraging.Thanks.. :( $\endgroup$
    – user411
    Commented Jul 10, 2012 at 11:55
  • $\begingroup$ @Manishearth see this meta question.. meta.stackexchange.com/questions/8724/… $\endgroup$
    – user411
    Commented Jul 10, 2012 at 16:12
  • $\begingroup$ @georg best fit. Unfortunately, the "general reference" option is only enabled as a trial on some sites. Still, current consensus seems to be that such questions ought to be discouraged. $\endgroup$ Commented Jul 10, 2012 at 16:52

1 Answer 1


Ozone gas does indeed have a slight blue color. It is dark blue in a liquid form and purple-black in solid form.

The color comes from the fact that it absorbs all wavelengths of light other than those in the blue region. As the phase changes, the molecules get closer together, shifting the area of absorption, changing the color of the material.