I have a confusion about the correct structure of tetraiodine nonoxide.
I came to know about it while reading the equation :

$$\ce{6 I2 (dry) + 11 O3 -> 3I4O9 + 3O2 }$$

Now again I saw the equation :

$$\ce{ I4O9 <=>I^3+(IO3-)3}$$

Now this equation and this is structures in chemistry stack exchange make me to understand that ($\ce{I4O9}$) has the following structure:

[![enter image description here][1]][1]


[![enter image description here][2]][2]


But when I saw the following structure (shown below 👇🏻) on Wikipedia I have a doubt about that which structure is correct:

[![enter image description here][3]][3]

On seeing all the structures, according to me, due to the small size of oxygen to iodine (large size) are unstable on it, therefore the structure 3 is not possible and structure 1 and 2 which are same structure are the correct structures of $\ce{I4O9}$.

  [1]: https://i.sstatic.net/kyhVhm.png
  [2]: https://i.sstatic.net/76e5Tm.png
  [3]: https://i.sstatic.net/nj98nm.png