The lattice-type-sensitive model for the melting entropy and enthalpy of nanocrystals has been presented based on a model for the size dependency of the melting point. In other words, the effect of the lattice and surface structure on thermal stability of nanocrystals has been discussed. The presented equations of the melting entropy and enthalpy have been compared to the experimental data of In and molecular dynamic (MD) simulation results of Ag nanoparticles. In addition, a minimum possible size of crystalline nanosolids has been calculated and compared to the experimental and simulation results of Pb and Al nanowires. Also a relation between the average coordination number of nanoparticles and their melting entropy and enthalpy has been presented. Consequently a minimum possible value for the average coordination number of crystalline nanoparticles has been calculated.