Finding Symmetry number of a molecule [closed]








**Closed.** This question is [off-topic](/help/closed-questions). It is not currently accepting answers.
 
 






---








 **Homework questions** must demonstrate some effort to understand the underlying concepts. For help asking a good homework question, see: [How do I ask homework questions on Chemistry Stack Exchange?](https://chemistry.meta.stackexchange.com/questions/141/how-do-i-ask-homework-questions-on-chemistry-stack-exchange)




Closed 3 years ago.








[Improve this question](/posts/129234/edit) 



[![Problem Statement](https://i.stack.imgur.com/xqicB.png)](https://i.stack.imgur.com/xqicB.png)


An isotopic variant of the molecule SF$\_6$ is S$^{19}$F$\_4^{18}$F$\_2$, with the two $^{18}$F nuclei oriented axially, so that the $^{18}$F-S-$^{18}$F angle is 180°and the four $^{19}$F nuclei form a square in a plane perpendicular to the $^{18}$F-S-$^{18}$F axis. All of the bond lengths are equal. In the figure, the regions surrounding the $^{18}$F nuclei are shown in blue, and the regions around the $^{19}$F nuclei are shown in green.Two of the moments of inertia of S$^{19}$F$\_4^{18}$F$\_2$ are identical, and the third is slightly larger: I$\_A$= I$\_B$ = $2.9942 ×10^{-45}$ kg m$^2$ and I$\_C$= $3.0749×10^{-45}$ kg m$^2$. Wikipedia describes SF$\_6$ as an “extremely potent greenhouse gas.”


What is the symmetry number of S$^{19}$F$\_4^{18}$F$\_2$? 


I have considered it and think there is one 4-fold axis, and two 2 fold axes, but still unsure if that is right


