Dear Community,

I'd like know some crystal structures for given compounds.

Can I predict the structure/unit cell, i.e. of Hydroxylapatite, just by giving Ca₅(PO₄)₃(OH)? (I know that structure :-) - just to check the method)

2. Question:

How can I build a unit cell using groups like OH- or PO₄ 3-  instead of atoms? / How do I predict/calculate the exact distances between the groups, when I know the crystal structure and the arrangement of those groups, but not the exact positions in the unit cell?

Thanks.

Romans