  We investigate the possibilities of using measurements in present and future
experiments on heavy ion collisions to answer some longstanding problems in
hadronic physics, namely identifying hadronic molecular states and exotic
hadrons with multiquark components. The yields of a selected set of exotic
hadron candidates in relativistic heavy ion collisions are discussed in the
coalescence model in comparison with the statistical model. We find that the
yield of a hadron is typically an order of magnitude smaller when it is a
compact multiquark state, compared to that of an excited hadronic state with
normal quark numbers. We also find that some loosely bound hadronic molecules
are formed more abundantly than the statistical model prediction by a factor of
two or more. Moreover, due to the significant numbers of charm and bottom
quarks produced at RHIC and even larger numbers expected at LHC, some of the
proposed heavy exotic hadrons could be produced with sufficient abundance for
detection, making it possible to study these new exotic hadrons in heavy ion
collisions.
