  We develop here a simple yet versatile model for nuclear fragmentation in
heavy ion collisions. The model allows us to calculate thermodynamic properties
such as phase transitions as well as the distribution of fragments at
disassembly. In spite of its simplicity the model gives very good fit to recent
data taken at the Michigan National Superconducting Cyclotron Laboratory. The
model is an extension of a lattice gas model which itself has strong overlaps
with percolation models which have been used in the past to compare with
nuclear fragmentation data.
