What kinds of three-dimensional nets are possible with tris-chelated metal complexes as building blocks?

Tris-chelated metal complexes with octahedral geometry are sometimes used as building blocks for "self assembly" and "crystal engineering". These versatile building blocks easily form honey-comb type 2D nets. However, in this Perspective we discuss the different types of 3D nets that can be formed with these starting materials using Wells classification, and concentrate on the (10,3) nets. We show that several of these, and not only the (10,3)-a net, are possible by analysing the geometrical requirements of each net. We note that each possible net implies a specific assembly order of Delta or Lambda chirality of the building blocks.