  We show in simulations that a rich variety of novel orderings such as
pinwheel and star states can be realized for colloidal molecular crystal
mixtures at rational ratios of the number of colloids to the number of minima
from an underlying periodic substrate. These states can have multi-step melting
transitions and also show coexistence in which one species disorders while the
other species remains orientationally disordered. For other mixtures, only
partially ordered or frustrated states form.
