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According to these sites:

  1. Chemistry Help

  2. Molbase

in $\ce{PCl2F3}$, both $\ce{Cl}$ and one $\ce{F}$ atom are on equatorial position, and other 2 $\ce{F}$ atoms are on axial position as follows:

enter image description here

The first site mentions that to minimise repulsions of $\ce{F - F}$ bonds. But this structure is in fact increasing the repulsions, and decreasing stability, since the bond angle of $\ce{F - P - F}$ bond will be about $\mathrm{90^\circ}$

If instead all the $\ce{F}$ atoms are on equatorial position, and the 2 $\ce{Cl}$ on axial positions, then the repulsion may be further minimized.

So according to me, the structure should be:

enter image description here

Question: Why is my structure wrong? Please explain. Thank you!

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Max Payne
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    See, the repulsion is not only between fluorines. – Ivan Neretin Feb 10 '16 at 12:03
  • @IvanNeretin But $\rm F$ on equitorial position is a menace for all. It will repel the two $\rm F$ on axial very strongly, and also repel the chlorine. – Max Payne Feb 10 '16 at 12:05
  • True, but chlorine would repel chlorine even stronger. – Ivan Neretin Feb 10 '16 at 12:06
  • @IvanNeretin Thats why i placed the $\rm Cl$ atoms on axial position. This also gives symmetry to molecule. The site I linked said that Fluorine's bond $e^-$ repel more strongly due to its greater electronegativity – Max Payne Feb 10 '16 at 12:10
  • Molecules do not care about symmetry. As for the repulsion, well, looks like the site was wrong on this one. – Ivan Neretin Feb 10 '16 at 12:17
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    Strongly related: http://chemistry.stackexchange.com/questions/18427/why-does-f-replace-the-axial-bond-in-pcl5/18544#18544 – bon Feb 10 '16 at 13:02
  • I am VTCing as a duplicate. The sole difference is the number of chlorines. – orthocresol Feb 10 '16 at 13:14

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