2
$\begingroup$

A perovskite is any crystal with the general formula $\ce{ABX3}$ where if the $\ce{B}$ atoms form a cube, an $\ce{A}$ atom sits in its center and the $\ce{X}$ atoms sit between neighboring $\ce{B}$ atoms.

Is the perovskite structure symmetric under exchange of $\ce{A}$ and $\ce{B}$ atoms? That is, if I replace every $\ce{A}$ atom with a $\ce{B}$ atom and vice versa, will I end up with the same exact structure as before?

Improve this question
$\endgroup$
2
$\begingroup$

No. In the perovskite structure, the "A" atoms are larger than the "B" atoms. The B atoms are 6-fold coordinated, while the "A" atoms are in 12-fold cuboctohedral coordination.

Improve this answer
$\endgroup$
1
  • 1
    $\begingroup$ I'd say the size is not the reason - the coordination/symmetry difference does the job to explain why the sites are not equivalent. The larger volume available in that center certainly helps explain why a larger atom likes it, but if it can't hack the coordination requirements it won't want to be a perovskite. $\endgroup$ – Jon Custer Jul 29 '16 at 0:40

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.