Using the isospin-dependent quantum molecular dynamics model, we study the stability of the fragments and the thermalization achieved in the collision of a neutron- rich colliding pair at energies where the maximum production of intermediate mass frag- ments (E max c.m. ) occurs. In particular, we check the stability of fragments through the persis- tence coefficient and gain term and information about the thermalization and stopping is obtained via the relative momentum, anisotropy ratio, and rapidity distribution. Our find- ings show a weak dependence of these quantities on the neutron content of the colliding pair. c.m. (the energy at which maximal production of intermediate mass fragments occurs) and found that for a complete stopping of incoming nuclei very heavy systems are required. The mass dependence of various quantities is found to follow a power law dependence. With the availability of radioactive ion beams (RIBs), it has become possible to study neutron- rich heavy-ion collisions. The neutron content of a colliding pair is found to affect the multifragment decay (7-14), collective as well as elliptic flow (15-17). Recently, Puri and co-worker (12) studied the isospin effects on the energy of peak mass production. Both E max c.m. (the energy at which maximal production of intermediate mass fragments occurs) andNIMFmax (the maximum number of interme- diate mass fragments) are found to be insensitive to the isospin dependence of the nucleon-nucleon cross section but E max.m. showed sensitivity towards the symmetry energy. One is, therefore, interested in understanding how nuclear dynamics behaves at this peak energy. A limited number of studies