Synthesis, crystal and electronic structures, and electrical properties of Rb 2Mo 12Se 14 containing trioctahedral Mo 12 clusters

Abstract

The synthesis of the new ternary molybdenum chalcogenide Rb 2Mo 12Se 14 is reported. It crystallizes in the trigonal space group R 3 with hexagonal lattice parameters a = 9.538 (2) and c = 24.66 (1) Å. The main structural building block of the crystal structure of Rb 2Mo 12Se 14 is the Mo 12Se 14 cluster unit, which is also found in Cs 2Mo 12Se 14. Electrical resistivity measurements performed on a single crystal indicate that Rb 2Mo 12Se 14 is a metallic conductor with an unusual temperature dependence of its resistivity. Moreover, a superconducting transition was observed at 2.5 K. Extended Hückel tight-binding (EHTB) calculations have been made and are discussed.