  Deviations from an idealized equilibrium phase transition picture in nuclear
multifragmentation is studied in terms of the entropic index. We investigate
different heat-capacity features in the canonical quantum statistical model of
nuclear multifragmentation generalized in the framework of Tsallis nonextensive
thermostatistics. We find that the negative branch of heat capacity observed in
quasi-peripheral Au+Au collisions is caused primarily by the non-generic
nonextensivity effects.
