  Our knowledge of binding energies of neutron-rich nuclei has experienced a
major revision during the last five years due to the introduction of
Penning-trap based mass measurements. New mass values for nearly 300 nuclides
produced in fission with uncertainties of 10 keV or less have become available.
The data produced at three Penning trap facilities at Jyvaskyla, CERN-ISOLDE
and Argonne cover all isotopic chains from Ni to Pr, except iodine. In this
talk some of this data is reviewed and applied using the mass differentials
such as two-neutron binding energy and odd-even staggering to probe their
sensitivity on changes in nuclear structure and on the strength of the N=82
shell gap and associated pairing effects.
