Rubidium molybdenum selenide, Rb4Mo21Se24, crystallizes in the trigonal spa
ce group R(3) over bar $. Its crystal structure consists of a mixture of Mo
12Se14Se6 and Mo15Se17Se6 cluster units in a 1:2 ratio. Both units are inte
rconnected through Mo-Se bonds. The Rb+ cations occupy large voids between
the different cluster units.