Superconductivity in a Molecular Metal Cluster Compound
  Compelling evidence for band-type conductivity and even bulk superconductivity below $T\_{\text{c}}\approx 8$ K has been found in $^{69,71}$Ga-NMR experiments in crystalline ordered, giant Ga$\_{84}$ cluster-compounds. This material appears to represent the first realization of a theoretical model proposed by Friedel in 1992 for superconductivity in ordered arrays of weakly coupled, identical metal nanoparticles. 
O. Bakharev, D. Bono, H.B. Brom, A. Schnepf, H. Schnoeckel, L.J. De   Jongh