A particular form of cinnabar (HgS) adopts the zinc blende structure. The length of the unit cell edge is 5.852 Å. (b) The mineral tiemannite (HgSe) also forms a solid phase with the zinc blende structure. The length of the unit cell edge in this mineral is 6.085 Å. What accounts for the larger unit cell length in tiemmanite?

Video transcript

Hello everyone. So in this video we want to explain why C. D. S. C. A larger cell primer than C. D. S. Let's go ahead and actually recall some information. We want to recall that ionic radius. It's just going to be the size of an ion. We actually have a periodic trend for this and we're going to speak in terms of increasing size. So pretend we have a puree table here. So wherever we're going from right to left were increasing and never we're going down api table or period in the periodic table, it's also increasing. So then S. C. Is below us in the same column of the periodic table. So I expected that S. C. Will have a larger radius. So this also goes ahead and implies that a larger unit cell for C. D. S. E. Is compared to R C. D. S. So the answer as to why C. D. S. C. A larger cell parameter than C. D. S. It is because S. E. Has a larger ionic radius than us and that's going to be my final answer for this problem. Hopefully this helped you all out