Question

I know that meso compounds have at least 2 chiral centers, however, can they have any achiral centers? Or are all of the centers chiral if it is meso?

Answer 1

No, they should always have chiral centers

Recall that First, we must identify the CHIRAL center(s). This is done via --> chiral center rule:

it must be bonded to 4 different types of "branches" that is, they should NOT repeat each other, such as CH3, CH3.. It should have all 4 substituents completely different.

if they repeat, they are not CHIRAL centers, therefore, they become achiral... in which they CANT be stereoisomerism on meso/entantiomers

Note that there is a point in which the molecule can be non-chiral, but the centers must be chiral