Diquark-antidiquarks with hidden or open charm and the nature of X(3872).

Heavy-light diquarks can be the building blocks of a rich spectrum of states which can accommodate some of the newly observed charmoniumlike resonances not fitting a pure cc* assignment. We examine this possibility for hidden and open charm diquark-antidiquark states deducing spectra from constituent quark masses and spin-spin interactions. Taking the X(3872) as input we predict the existence of a 2++ state that can be associated to the X(3940) observed by Belle and reexamine the state claimed by SELEX, X(2632). The possible assignment of the previously discovered states Ds(2317) and Ds(2457) is discussed. We predict X(3872) to be made of two components with a mass difference related to mu - md and discuss the production of X(3872) and of its charged partner X+- in the weak decays of B+-;0.