With the exception of Zn, Hg, Cd and Mn transition metals most transition metals have only one kind of lattice structure at room temperature. Another trend I noticed was that Groups 3 and 4 have hexagonal close packing; 5 and 6 have Body-centred cubic cells; Groups 7 and 8 (with the exception of Iron) have hexagonal close packing; and the last 3 groups have cubic close packing.
Even at higher temperatures, Groups 3 and 4 usually show usually show body-centred cubic packing (Lanthanum is an exception).
I know that in ionic compounds, we can find the type of packing by comparing the ratio of radi, is something like this going on here? But if that were the case the radi and thus the structure would drastically change down the group (which is not happening); so it must have something to do with the electronic configuration. Can someone help, thanks.