  We study the cluster structure of 21Ne and 21Na within the framework of the
cluster shell model (CSM) and show that they have a complex cluster structure
with the coexistence of a 20Ne+n, 20}Ne+p structure and a 19Ne+2n, 19}F+2p
structure. Seven rotational bands are identified in 21Ne and four in 21Na and
assigned to single-particle cluster states, single-hole cluster states and
vibrational states. The single-particle states are associated with the 20Ne+n
and 20Ne+p cluster structure, while the single-hole states are associated with
the 19Ne+2n and 19F+2p structure.
