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Superconductivity is observed below Tc= 1.6 K in an endohedral Ga cluster compound PdGa5using magnetization and heat capacity measurements. Electronic structure calculations show that the density of states (DOS) at the Fermi level is dominated by Ga sand pstates and that the overall shape of DOS is similar to what was found in other endohedral Ga cluster superconductors, such as MoxGa5x+1, ReGa5, and T2Ga9(T= Rh and Ir). Our results provide a more complete picture of the relationship between the valence electron count and superconductivity in the family of endohedral Ga cluster superconductors.

Three new salt inclusion compounds (CsX)Cu5O2(PO4)2(X= Cl, Br, I), phosphate analogues of the kagomé mineral averievite, are reported. Their crystal structures are composed of trigonal networks of corner-sharing OCu4anion-centered tetrahedra, forming capped-kagomé planes, which can also be regarded as two-dimensional slices along the [111] direction of a pyrochlore lattice. Magnetization and heat capacity measurements reveal strong geometric frustration of this network and complex magnetic behavior. X-ray and neutron diffraction studies show that all three compounds undergo a trigonal-to-monoclinic phase transition upon cooling, with a first-order phase transition seen in CsBr and CsI analogues. Along with the previously reported (CsCl)Cu5O2(VO4)2, these three new compounds belong to a large family of OCu4-based networks, which are a playground for studying frustrated quantum magnetism.