Abstract
The disordered structure of the zero-dimensional hydrogen-bond type crystal Rb 3 H(SeO 4 ) 2 was determined in the high-temperature trigonal phase. The observed Rb(1)-O(1a) atomic distances are considerably shorter than the other Rb-O. The structure refinement revealed that SeO 4 tetrahedra have disordered arrangements implying the existence of the steric hindrance between Rb atoms and SeO 4 tetrahedra. The steric hindrance between Rb and SeO 4 dominates the ferroelastic phase transition.