STRUCTURE AND MAGNETIC-PROPERTIES OF 2 NIOBIUM CHLORIDES WITH (NB6CL12)N+ (N=2, 3) UNITS - KLUNB6CL18 AND LUNB6CL18

The quaternary chloride KLuNb//6Cl//1//8 and the ternary chloride LuNb//6-Cl//1//8 were synthesized. They crystallize in the rhombohedral lattice R3 OVER BAR and exhibit vertical Nb//6Cl//1//2 vertical **2** plus and vertical Nb//6Cl//1//2 vertical **3** plus units respectively. In the first case, the Nb//6Cl//1//2 vertical **2** plus unit has 16 e** minus per Nb//6 and the cluster is non-magnetic; in the second case, the vertical Nb//5Cl//1//2 vertical **3** plus unit has 15 e** minus per Nb//6 and the cluster is paramagnetic owing to one unpaired electron. We present here the synthesis of these compounds, the structural results and the magnetic properties which depend on the variation in the oxidation state of the cluster.