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Anne Marie Helmenstine, Ph.D.

Red Oxygen and Black Oxygen

By February 9, 2014

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Red OxygenYou know oxygen in air is colorless and you may have heard that liquid oxygen is pale blue, but did you know oxygen also occurs in pink, orange, red, black, and even a metallic form? At atmospheric pressure, liquid oxygen cools into solid oxygen, which forms blue crystals. However, as the pressure is increased and/or the temperature is lowered, phase transitions occur that change the structure of oxygen and also its color. Six phases of solid oxygen are known:
  • α-phase: light blue -- forms at 1 atm below 23.8 K, monoclinic crystal structure
  • β-phase: faint blue to pink -- forms at 1 atm below 43.8 K, rhombohedral crystal structure (at room temperature and high pressure, transforms to tetraoxygen, O4)
  • γ-phase: faint blue -- forms at 1 atm below 54.36 K, cubic crystal structure
  • δ-phase: orange -- forms at room temperature at pressure of 9 GPa
  • ε-phase: dark-red to black -- forms at room temperature at pressures greater than 10 GPa
  • ζ-phase: metallic -- forms at pressures greater than 96 GPa
Tetraoxygen (O4) is a transient state, although octaoxygen (O8) is stable. The metallic phase of oxygen exhibits superconductivity.

Image: The octaoxygen or O8 molecule, which forms red crystals.


February 22, 2013 at 4:23 am
(1) Mohammad Irandoost says:

hey thanks for your useful and pithy texts. they are very useful for me (I’m a chemistry teacher in Iran). do it again!

February 25, 2013 at 3:51 am
(2) Shehu Aliyu yusuf says:

Hello thank you very much, I am really enjoying your site, keep on.

February 25, 2013 at 6:07 am
(3) Shitalkumar says:

Thanks mam, for the informstion about oxygen.

February 25, 2013 at 7:22 am
(4) Kavitha says:

Really its useful information only. I never knew that O2 have these colors. thank you very much.. But I need depth detail about colors of O2

February 25, 2013 at 8:40 am
(5) George Ntibarikure says:

Wow, how would I know about this without you? Many thanks!

February 25, 2013 at 8:48 am
(6) sarita says:

thank you so much..

February 25, 2013 at 1:00 pm
(7) Francis Ayotunde says:

Thanks for your post,u are doing a wonderful job.

February 25, 2013 at 1:21 pm
(8) David Luken says:

This is a wonderful service you are providing. They wouldn’t let me take chemistry in high school because I couldn’t master Algebra. Half a century later, I’m finally learning what I’ve long longed to study.

February 25, 2013 at 3:59 pm
(9) r.janarthanam says:

informative. making me deeply interested in chemistry/ur articles.
verymany thanks for ur dedicated service

February 26, 2013 at 2:07 am
(10) Annadhasan says:

Its really awesome……. i need these kind of experiments in detail to demonstrate and make people to like and love chemistry…….. if possible send me the details to do the experiments at room temperature…..

February 26, 2013 at 3:57 am
(11) selvashahana says:

thank mam, for telling about a nice topic

February 26, 2013 at 10:01 am
(12) ahmed says:

dat is wats up!

February 26, 2013 at 8:41 pm
(13) abssnmjyhhj@ sympacio.net says:

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February 27, 2013 at 1:53 am
(14) Swati says:

Hi, you are providing us with additional knowledge which can be useful to us in our teaching process. This is a very good job that you are doing. Thanks a ton! Keep sending

February 27, 2013 at 2:08 am
(15) Masoka says:

You ve really expanded my horizons in chemistry after knowing about red, pink and black oxygen. Keep it up. Bring mAny more surprises!
Am a teacher trainer in Chemistry

Masoka Nairobi, Kenya.

February 28, 2013 at 5:19 am
(16) avijit says:

i really don not know about these thank you very much

February 28, 2013 at 7:22 am
(17) zahra says:

thanks very much, your articles very much useful

February 28, 2013 at 8:49 am
(18) Sanjeev Kulkarni says:

A lot of important information about Oxygen. Thanks. A study is required to be done regarding using these different type (rather forms) of Oxygen for porification of water & confined space, economically.

February 28, 2013 at 10:12 am
(19) prakash shendge says:

thank u these is important

February 28, 2013 at 10:22 am
(20) mukesh kumar says:

Thanks mam for giving me advanced knowledge about 0xygen

February 28, 2013 at 12:43 pm
(21) munish says:

nice mam it is useful to my career also our student future

March 1, 2013 at 2:15 pm
(22) usman says:

Thank you mam………I really appreciate your hard working keep it up

March 2, 2013 at 2:12 am
(23) tahira says:

m really impressd .one can get alot from here .thnx

March 3, 2013 at 6:10 am
(24) nataraj 09 says:

million thanks for the great story..!

March 6, 2013 at 1:01 pm
(25) irum aamir says:

hi i am a chemistry teacher from Pakistan. i am very thankful to you to share such an interesting information and i would like to share it with my students in school. i did not know that oxygen exists in many colors.

March 6, 2013 at 1:17 pm
(26) irum aamir says:

i like your information that oxygen exists in many colours.

A chemistry teacher from Pakistan

March 22, 2013 at 8:43 am
(27) Zhang Jiachen says:

Thank you very much!You help me know more about oxygen!

April 22, 2013 at 1:16 pm
(28) devendra kumar says:

thanks to provide all informations

May 1, 2013 at 4:10 am
(29) fasi says:

doing a great job , ur info is always valuable. thanx for all that

May 4, 2013 at 4:30 pm
(30) doc moto says:

Excellent, an application to certain everyday use would be greatly appreciated. Perhaps the combination of NaClO2 and a soft catalyst such as C2H4O2 and under certain collective arrangement to reflect the display of collected gases, including O2. It would be nice to have the laboratory environment to collective pull O2 when forcing varied DC current through an aqueous solution to separate its liquid state at the varies atmospheres! Thanks for your collective note doctor.

December 11, 2013 at 2:55 am
(31) Cyprian Anyahucha says:

Great. Thanks for the article. It’s really interesting.

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