For each unit cells given below, determine the chemical formula of the A$-$B compounds.

Provide reasons for your findings. Note that A atoms $($or ions$)$ are the solid grey circles and B

are the open circles in figures $($a$),($b$)$ and $($c$).$ A atoms are the smaller and B atoms are the

larger atoms in figure $($d$).(16$ points$)$

$($b$)$

$($c$)$

$($d$)$