The results on chemical reactions of metal atoms, small clusters and nanoparticles with different organic and inorganic substances in the temperature range 12-300 K are presented. Complexation and reactions of atoms and clusters of magnesium, samarium and silver with alkyl halides, carbon dioxide, ethylene and some mesogenic cyanophenyls were studied by the technique of matrix isolation and low temperatrure co-condensation of metal and ligands vapours, low temperature UV-Vis. IR- and ESR-spectroscopy in the combination with quantum chemistry calculations. In some cases the reaction products were analysed by high performance gas chromatography. It was shown that cryochemical reactions of metal particles of different size reflected the system redundant energy.