In a ideal unit cell of perovskite $\ce{KMnF3}$ (closed packed with purely ionic bondings), calculate the unit cell length:
radius: $\ce{K}=1.7~$ $\ce{F}=1.2~$ $\ce{Mn}=0.8$
Green $\ce{K}$, red $\ce{F}$, blue $\ce{Mn}$. (ignore the sizes in the picture)
Am I going right by using the $\ce{F-K-F}$ diagonal length to calculate the cell length using pytagroas, as the Mn diameter is to small and therefore the $\ce{Mn-F-Mn}$ will have some spacing on it and are not fully adjacent.
I would get unit cell length =4.101. can somebody confirm this?
Just a bit confused as I have the radius of $\ce{Mn}$ but don't use it for calculation
Many Thanks