To make my question more clearly, i want to ask two questions.

Is it possible for molecule to be achiral even though molecule has chirality center?

And is it possible for molecule to be chiral even though molecule doesn't have chirality center?

I thought this question because the definition of chirality center and chiral is not match to one to one correspondence.

Chirality center is defined by CXYZW and chiral is defined by nonsuperimposable by mirror plane. It does quite related but i think there will be counterexample that satisfying one condition but not satisfying the other one.