What is the structure of $\ce{Br3O8}$? It has an odd number of electrons; does that make it a free radical?

The structure given in my book shows

enter image description here

Where did the 7th electron of the central atom go?

Picture from book (Pg 265, NCERT Chemistry Part II, class 11):

Pic from book


1 Answer 1


The electron didn't go anywhere. It's in an unhybridized p orbital on the central bromine, and yes, $\ce{Br3O8}$ is a free radical. That is why it decomposes above -80ºC.$^{[1]}$

$^{[1]}$ Cotton, F. A. Progress in Inorganic Chemistry - Volume 2; Interscience Publishers: New York, NY, 1960.

  • 1
    $\begingroup$ Thanks. That clarifies everything. Isn't it mandatory to mention a free radical to be so in the bond structure? $\endgroup$ Feb 14, 2017 at 14:18
  • 2
    $\begingroup$ Yes, @ghosts. If the structure drawing in your book doesn't indicate in some way that there is a free radical, then it is very likely a misprint. Look closely and make sure there isn't a dot somewhere around the Br atom! $\endgroup$ Feb 14, 2017 at 14:57
  • $\begingroup$ @CodyGray The asterisk has a different meaning indicated in the text. So no dot then :P $\endgroup$ Feb 14, 2017 at 15:13
  • 1
    $\begingroup$ I see a number of basic copyediting errors in the text surrounding the structures - I think this is not a very good textbook. $\endgroup$
    – zwol
    Feb 14, 2017 at 21:00
  • 12
    $\begingroup$ @zwol There are many questions and answers on our site that use NCERT texts. I find them insufficient and outdated at best, sometimes they are even outrageously wrong; it often looks like they have been effortlessly copy & pasted together from already bad sources. $\endgroup$ Feb 15, 2017 at 4:50

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.