Charge-Density Waves In Mono3n-1

Single crystals of Mo n O 3n−1 (n=8, 9 and 10) have been studied by four circle x-ray diffraction, neutron scattering and other conventional methods. There have been found the superlattice reflections for all the compounds possibly due to the formation of charge density waves (CDW). The anomalous temperature dependence of the resistivities in Mo 8 O 23 and Mo 9 O 26 can be understood by these transitions. The condensed modes in all the compounds have the similar characters. The present system may give an example of superconductivity-CDW competition.