The combustion energies have been determined for the thirteen solid complexex of rare earth nitrates with glycine. The standard enthalpies of combustion, Delta(c,(coor)H-, and standard enthalpies of formation, Delta(f,(coor)H- have been calculated for these complexes, The relationship of Delta(f,(coor)H- with the atomic numbers of the elements in the lanthanide series has been examined. The results show that a certain amount of covalency is present in the chemical bond between the rare earth cation and glycine.