Currently, the literature reveals several classes of substances with ferromagnetic interaction between paramagnetic ions: clusters (d-f) with Schiff Bases; carboxylate clusters, heterometallic cyanides, homo-and heterometallic oxalates and oxalamides. Magnetization of individual molecules of some complexes of these substances’ classes behaves analogous to ordinary magnets (type - ferrites). Clusters possessing such properties have been called Single Molecule Magnets (SMMS). The “bioinorgnic chemistry and nanocomposites” laboratory of the Institute of Chemistry of the Academyi of Sciences of Moldova’ investigations have demonstrated that in the list of substance’ classes with SMMS properties the heteronuclear carboxy-clusters containing {Fex Lny} fragment may be included.