[Big-Daddy]

I recently came across problems asking us to draw the Lewis structure of N₅⁺, cyclic N₅^-, P₄, P₄O₆, P₄O₁₀, P₃O₁₀^5-, P₃O₉^3-, S₄O₆^2-.

I really enjoyed these. Can anyone say where I might find some more of this type of problem? (i.e. larger-than-usual and pretty complicated polyatomic inorganic molecules or ions).