Group 1 and 2 suboxides and subnitrides - metals with atomic size holes and tunnels

Alkali metal suboxides and the closely related subnitrides of alkaline earth metals represent a unique class of compounds. Their structures are composed of discrete clusters (Rb9O2, Cs11O3, Ba6N,Ba14CaN6) which form stoichiometric compounds with alkali metals like Rb9O2Rb3 = Rb6O, Cs11O3Cs10 = Cs7O Cs11O3Rb7, Na16Ba6N or Na22Ba14CaN6. In the structures of NaBa3N and Na5Ba3N chains of condensed clusters are embedded in alkali metal. All compounds are metalic. Due to the cumulation of negative charges by O2- and N3- ions inside the clusters the conduction electrons reside in the space between the clusters. Electronic confinement in space leads to interesting physical properties. (C) 1997 Elsevier Science S.A.